ML20215M618
| ML20215M618 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 05/08/1987 |
| From: | Williams N CYGNA ENERGY SERVICES |
| To: | Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| References | |
| PROC-870508, NUDOCS 8705140056 | |
| Download: ML20215M618 (180) | |
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TU Electric Comanche Peak Steam Electric Station Unit 1 Independent Assessment Program All Phases Cable Tray Support Design Review Review Issues List r
P.evision 13 l
\\
l Prepared by:
Cygna Energy Services i
2121 N. California Blvd.,
Suite 390 d
[ k
'l Walnut Creek, CA 94596 l
E#"2288nogggg May 8, 1987
05/08/87 Revision 13 Page i CABLE TRAY SUPPORTS Review Issues List Table of Contents Issue No.
Issue Title Page INTRODUCTION................................................
1 1.
Controll i ng Load Case for De s i gn............................
3 2.
Seismic Response Combination Method.........................
6 3.
Anchor Bolt Design..........................................
9
{
4.
De s ign o f Comp res s ion Membe rs...............................
27 5.
Vertical and Transverse Loading on Longitudinal............
35 Type Supports 6.
Support Frame Dead and Inertial Loads.......................
37 7.
Design of Angle Braces Neglecting Loading Eccentricity......
41 8.
Dynamic Ampli fication Factors (DAF). Tributa ry..............
46 Tray Support Reactions and Missing Mass Effects 9.
Reduction in Channel Section Properties Due to Clamp.......
50 Bolt Holes 10.
System Concept..............................................
53 11.
Val i d i ty o f N ASTR AN Model s..................................
58 12.
Working Po i nt Devia tion Study...............................
60 13.
Reduc ed S pec tral Accel e ra tions..............................
67 14.
Non-Con formance with AISC Speci fications....................
70 TU Electric Comanche Peak Steam Electric Station
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CABLE TRAY SUPPORTS Review Issues List Table of Contents Issue No.
Issue Title Page 15.
Member Substitution.........................................
76 16.
Wel d Desi gn and Speci fi ca tions..............................
79 17.
Embedded Plates Design......................................
87 18.
Cable Tray Clamps...........................................
91 19.
FSAR Load Combinations......................................
97 20.
Differences Between the Installation and the...............
99 Design / Construction Drawings 21.
Design Control..............................................
116 22.
Des i gn o f Support No. 3136. Detail "5",
136 Drawing 2323-S-0905 24.
De s i gn o f Fl exu ral Members..................................
140 25.
Ca bl e Tray Qual i fica tion....................................
149 26.
Base Angle Design...........................................
156 27.
Support Qual i fication by Similarity.........................
158 28.
Critical Support Configurations and Loadings................
161 29.
Cumulative Effect o f Review Issues..........................
163 30.
Ca bl e Tray Dampin g Val u es...................................
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Issue Title Page 31.
' Modell ing o f Bou nda ry Co ndi tions............................
167 32.
Condu i ts Attac hed to Ca bl e Trays or Supports................
168 33.
As-Built Walkdown Procedures................................
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Review Issues List l
l INTRODUCTION This document sumarizes the major issues which have arisen from the review of the design and installation of the Cable Tray Supports at Comanche Peak Steam Electric Station (CPSES). This review was conducted as a part of the Independent Assessment Program (IAP) performed by Cygna Energy Services for TU Electric (formerly Texas Utilities Generating Company (TUGCO)).
The various issues discussed here are the result of a review of the design documents (e.g. calculations, drawings and design changes) generated by Gibbs
& Hill, Inc. and TU Electric; installation documents (e.g., assenbly drawings, fabrication procedures, quality assurance procedures, etc.) generated by TU Electric and Brown & Root, Inc; and a walkdown of the installed cable trays and supports. located in CPSES, Unit 1.
The Cable Tray Support Review Issues List (RIL) is a tracking document which provides a summary description of each issue, a list of relevant reference documents, a discussion of the methods used to resolve the issue and a brief statement on the status of the resolution.
During the course of the IAP, an effort was made by the Project (Gibbs & Hill, Inc., TU Electric and Brown & Root, Inc.) to resolve each issue through revisions to the existing design calculations, the generation of new calculations and the issuance of design change documents.
In some cases, it was not possible to resolve certain issues in that manner, while in other cases Cygna did not accept the resolution provided by the Project.
In October,1984, TU Electric created the Comanche Peak Response Team (CPRT) to develop a unified approach for the resolution of all design and construction issues associated with the licensing of CPSES. A program plan was developed by the CPRT which is entitled the "CPRT Program Plan and Issue-Specific Action Plans", Revision 3.
Appendix C of the Plan, " Civil /
Structural Discipline Specific Action Plan (DSAP VIII)", provides an outline of the approach followed by the Project to resolve the Cable Tray Support Review Issues identified by Cygna and others.
TU Electric has contracted two consultants Impell Corporation and Ebasco Services Inc. to perform a 100% as built evaluation of the cable tray support designs at CPSES in accordance with DSAP VIII.
Impell is responsible for the cable tray systems located in the Unit 1 Safeguards and Reactor Buildings, TU Electric Comanche Peak Steam Electric Station L
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05/08/87 Revision 13 Page 2 CABLE TRAY SUPPGtTS Review Issues List while Ibasco is responsible for the cable tray systems in the balance of Unit 1 and all of Unit 2.
Both Impell and Ebasco developed a series of design criteria, work instructions and generic calculations to guide the evaluation effort and address each of the review issues. These documents are provided as a part of the " Generic Issues Report for Evaluation and Resolution of Generic Technical Issues for Cable Tray Hangers", Revision 2 (GIR).
Revision 13 of the Cable Tray Support RIL incorporates the responses provided in the GIR, in conbination with the results of a ptblic meeting between Cygna and the CPSES Project and several audits of Impell and Ebasco's as-built evaluation program. This information has been used to update the status of each issue and in some cases to regroup several interrelated issues.
l 4
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Controlling 1.oad Case for Design
References:
1.
Gibbs & Hill Calculation Binder 2323-SCS-101C, Set 5, Sheets 16-20 Revision 5 2.
Comunications Report between P. Huang, S. Chang (Gibbs
& Hill) and J. Russ, W. Horstaan (Cygna) dated Novenber 13, 1984 3.
Gibbs & Hill Calculation Binder 2323-SCS-101C, Set 5, Sheets 1-7, Revision 1 4
CPSES FSAR, Sections 3.8.3 and 3.8.4 5.
Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 2", Revision 6 6.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for CPSES, Nos.1 and 2", Revision 4 7.
Impell Instruction PI-02, " Dynamic Analyses of Cable Tray Systems", Revision 5 8.
Impell Instruction PI-03, " Qualification of Cable Tray Supports", Revision 4, with Addendum 9.
Impell Instruction PI-07, " Design Verification of Base Plates, Base Angles and Enbedded Plates," Revision 3, with Addendum
- 10. ASME, " Boiler and Pressure Vessel Code"Section III, Stbsection NF,1983 edition 11.
Comunications RepErt between S. Harrison, J. Nandi (TV Electric); G. Ashley, B. Ramsey (Impell); R. Alexandru, S.J. Chen, P. Harrison, F. Hettinger (Ebasco); and TU Electric Comanche Peak Steam Electric Station kJL A Independent Assessment Program - All Phases lillililli::
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S. Tumminelli (Cygna) dated February 12, 1987
- 12. AISC, " Specifications for the Design, Fabrication and Erection of Structural Steel for Buildings", 7th edition Samasry:
Gibbs & Hill used the equivalent static method to design the cable tray supports. For all load cases, the equivalent.
static accelerations used in designing the supports for SSE events are less than 160% of the corresponding accelerations for 1/2 SSE (08E) events. Based on this fact and a review of Section 3.8.4 of the CPSES FSAR which allows a 60%
increase in allowables for structural steel when designing for the SSE event, Gibbs & Hill determined that the design was governed by the OBE event (Reference 3).-
To validate this conclusion, the 60% increase in allowables must be liberally interpreted to be applicable to all support cogonents rather than applicable only to structural steel as specified in the CPSES FSAR. Catalog items such as Richmond Inserts and Hilti Kwik 4olts do not have increased allowables for SSE events. By designing these catalog components to the OBE event, the manufacturer's design factor of safety is not iglicitly maintained for the SSE event.
Furthermore, for the design of structural steel, the 60%
i i
increase in allowables is acceptable for axial and strong-axis bending stresses in structural menbers.
The 60%
l increase cannot be applied to certain other allowable stresses. For example, the maximum increase in base plate l
stresses may only be 33%, at which point the material yield l
1s reached. A limit on maximum allowable stress is not provided in the FSAR.
I These limitations were not considered in the selection of the governing seismic load case.
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Response
Ige 11 and Ibasco will perform a 100% reanalysis for both the 08E and SSE loads assuming 4% and 7% critical damping, respectively, for the cable tray support systems.
(See Issue No. 30.) Unfactored AISC (Reference 12) alloweles for structural steel are used for the OBE load case. For the SSE load case, the AISC allowables are increased by 60%,
with tensile and bending stresses limited to 0.9 Fy and cogression stresses to 0.9 Fcr.
Factors of safety for catalog components (i.e., Hilti expansion anchors and Richmond Inserts) are established for each load case.
(See Issues 3.8 and 3.E.) Factors of safety of 5.0 and 4.0 are used for Hilti Kwik-bolts and Super Kwik bolts for the OBE and SSE load cases, I
respectively. A factor of safety of 3.0 is used for Richmond Inserts for both load cases.
Ebasco's implementation of this approach is discussed in Reference 5. Sections III.4 and IV. Sections 3.3.5 and 3.3.6 of Reference 7. Section 4.1.1 of Reference 8 and Sections 4.1.3 and 5.1 of Reference 9 discusses Impe11's iglementation.
Status:
This issue is open relative to the allowable stresses for cogonents governed by non-ductile failures (i.e., cogres-sive stress allowables in the region governed by Euler buckling and bending stress allowables governed by lateral torsional buckling or local instability) under the SSE loading.
Cygna believes that allowable stresses consistent with the ASME Code Section III, S@section W (Reference
- 10) may be more appropriate for these situations.
(See Reference 11.) This issue is closed for all other allowable stresses, Hilti expansion anchors, and Richmond Inserts.
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- 2. - Seismic Response Co41 nation Method,
References:
1.
CPSES FSAR Section 3.78.2.7 2.
Gibbs & Hill Calculation " Working Point Deviation Study" Binder No. 2323-SCS-215C, Sets 2-6 1
3.
US Ntc Regulatory Guide 1.92, Revision 1 4.
N.H. Williams (Cygna) letter to J.B. George (TUGCO)..
" Cable Tray Support Design Review Questions," 84056.031, dated August 31, 1984 5.
Gibbs & Hill Calculation in response to IAP Phase 2 questions, Cygna Technical File 83090.11.2.1.50 6.
Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 1", Revision 3 and SAG.CP 3 " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 2", Revision 6 7.
Ebasco Instruction, " General Instruction for Cable Tray Hanger Analyses for CPSES Nos. I and 2", Revision 4 8.
Ispell Instruction PI-02, " Dynamic Analysis of Cable Tray Systems" Revision 5 9.
Comunications Report between S. Harrison, J. Muffett (TU Electric); R. Wheaton, 8. Ramsey (Impell);
P. Harrison (Ebasco); and N. Williams, S. Tumminelli, D. Leong, J. Russ and W. Horstaan (Cygna) dated March 6, 1987 Samanry:
A.
Closely Spaced Modes (10% Modal Conbination) in Spectral Analysis In the response spectra analyses performed for the Working Point Deviation Study (Reference 2), Cygna noted ML TU Electric Comanche Peak Steam Electric Station L
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' Page 7 CABLE 1 RAY SUPPGt15 Review Issues List that adal responses were not cosined considering closely. spaced edes as required by References 1 and 3.
B.
Inclusion of Dead Load in SRSS Cotination In all Gibbs & Hill design calculations, the acceleration due to deadweight is cosined with the seismic accelerations using the SRSS method. A 1.0 g deadweight acceleration is first added to the vertical seismic acceleration. The sum is then cos ined with the two horizontal seismic cogonents using the SRSS method.
Response
A.
Ebasco, in Section IV.3.C of Reference 6, and Ispell, in Section 3.3.5 of Reference 8, indicate that the modal components of response from response spectrum analyses will be cosined in accordance with US Ntc Regulatory Guide 1.92 (Reference 3).
B.
Ebasco, in Attachment F of Reference 7, and, Impe11, in Sections 3.3.2, 3.3.5 and 3.3.6 of Reference 8, indicate that the results of the dead weight analyses will be conbined with the SRSS of the three directional co gonents of the seismic analysis. The following cos inations are used:
Where:
DW = dead weight forces / stresses (signed)
SEISMIC = seismic forces / stresses (unsigned)
Status:
A.
Closed.
B.
Open: The load cosination methods used by Impell and Ebasco may not result in the muimum menber stress i
interaction ratios or anchor bolt loads. This is due to treatment of the unsigned seismic forces / stresses. By performing the conbinations DW + SEISMIC or DW -
SEISMIC, all seismic forces / stresses are taken to have WL TU Electric Comanche Peak Steam Electric Station A
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Page 8 CABLE 1 RAY SUPPGtT5 Review Issues List the same sign. The possibility that certain cogonents of seismic forces / stresses may have opposite signs is not considered.
This concern was discussed in Reference 9.
A response is pending.
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CABLE TRAY SUPMRT5 Review Issues List 3.
Anchor Bolt Design
References:
1.
Gibbs & Hill Calculations, " Evaluation of Detail 1 f
Single-flolt Connection," Cygna Technical File 84056.11.1.259 2.
Gibbs & Hill Calculation " Aux. Building Cable Tray Supports" Binder No. SCS-212C, Set 7. Sheet 4-11 Revision 0 3.
Gibbs & Hill Calculations " Justification of the Adequacy of 1" Richmond Inserts For the Effects of j
Prying Action," Cygna Technical File 84056.11.1.219 4.
Brown & Root Procedure CEI-20, " Installation of Hilti Drilled-In Bolts," Revision 9 5.
Hilti, Inc., " Architects & Engineers Anchor and Fastener Design Manual" 6.
TUGC0 SDAR CP-80-12. " Reduced Allowable Loads for Hilti Kwik-bolts" 7.
TUGC0 Instructions CP-EI-4.0-49, " Evaluation of Thermo-Lag Fire Barrier Material on Class IE Electrical Raceways," Revision 1 8.
US PRC Inspection Reports 50-445/81-14; 50-446/81-14, dated 10/27/81 9.
Comunication Report between R.M. Kissinger (TUGCO);
B.K. Bhujang et al. (Gibbs & Hill); and W.R.
Horstman, et al (Cygna) dated 10/10/84 10.
N.H. Williams (Cygna) letter to W.G. Counsil (TUGCO), " Cable Tray / Conduit Support Review Questions," 84056.089, dated October 21, 1985 TU Electric Comanche Peak Steam Electric Station L.
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- 11. US Ntc Office of Inspection and Enforcement. IE Bulletin No. 79-02
- 12. American Concrete Institute " Code Requirements for Nuclear Safety 4telated Concrete Structures (ACI 349-76)"
- 13. Gibbs & Hill Interoffice Memo, T.D. Hawkins to M.
Strange, dated 7/25/84
- 14. Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cable Tray Hangers for CPSES Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 2", Revision 6
- 15. Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for CPSES Nos. I and 2",
Revision 4 16.
Ebasco Calculation, " Comanche Peak SES Cable Tray Hanger Volume 1", Book 3. " Prying Action Factors &
Formulas for Evaluating Anchor Bolts", Revision 1
- 17. Ebasco Calculation, " Comanche Peak SES Cable Tray Hanger Volume 1", Book 11. " Concrete Compressive Stresses under CTH Anchorage Shims and Base Plates".
Revision 0 18.
Igell Instruction PI-07, " Design Verification of Base Plates, Base Angles and Enbedded Plates",
Revision 3 19.
Igell Instruction PI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 20.
Impe11 Instruction PI-11. " Cable Tray System Analysis and Qualification Closecut". Revision 1 TU Electric Comanche Peak Steam Electric Station L
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Impell Special Study No. 5.2, " Diamond Cored Bolt Holes", Preliminary Issue 27.
Gibbs & Hill Specification 2323-S5-30, " Structural Embedments" Revision 2 28.
Comunications Report between S. Harrison, R.
Hooten, J. Muffett, J. Redding (TV Electric); R.
Alexandru P. Harrison E. Odar. M. Strehlow.
(Ebasco); G. Ashley, R. Grsb, B. Ramsey (Impe11);
and J. Russ, D. Leong, S. Tuminelli, W. Horstman, N. Williams (Cygna), dated February 13, 1987, 11:30 a.m.
29.
Transcripts of Cable Tray Hanger Design Verification Meeting between TV Electric, Cygna. Ebasco and Impell held at the CPSES site on January 26 and 27, 1987 30.
Ebasco Calculation, " Comanche Peak SES Cable Tray Hanger Volume I", Book 12. "CTH Anchorage Base Plate Flexibility Study", Revision 0 31.
Impe11 Calculation M-04, " Base Angle Stiffness",
Revision 1 32.
J. Metcalf (Hilti) letter to J. Russ (Cygna), " Data sheets for pullout performance of Kwik bolts", dated February 3,1987.
Summary:
A.
Frame Connection Point and Anchor Bolt Pattern l
Centroid Eccentricity In the design for the anchor bolts, Gibbs & Hill did not properly account for the eccentricity between the frame connection point to the base angle and the anchor bolt pattern centroid. The moment due to the eccentricity may cause the base angle to rotate about its longitudinal axis, resulting in: (1)a TU Electric Comanche Peak Steam Electric Station L &
Independent Assessment Program - All Phases Illillililleillestilillililill Job No. 84056 PRJ:RIL
05/08/87 Revision 13 Page 12 CABLE TRAY SUPPGtTS Review Issues List compressive force along the toe of the angle section and (2) additional tension in the anchor bolt (s).
B.
Safety Factor on Hilti Expansion Anchors at SSE Levels Gibbs & Hill's cable tray support designs employed a safety factor of 4.0 for Hilti expansion anchors for the 1/2 SSE load level. As discussed in Issue No.1, the 1/2 SSE event was assumed to govern the support designs, without consideration of the reduced factor of safety on Hilti expansion anchors for the SSE event. The safety factor for the SSE event will range from 2.5 to 3.0, depending on building and floor elevation.
C.
Inconsistent Application of ACI 349-76, Appendix B Gibbs & 11111 has used the provisions of Reference 12 to qualify several designs. Examples include the qualification of anchorages for Detail "11" (Gibbs &
Hill Drawing 2323-S-0905, Reference 2) and the use of code provisions as justification for the factors of safety used for Richmond Inserts.
However, the designs do not cogly with other sections of ACI 349-76, Appendix 8.
For exagle, Section B.7.3 states:
A single expansion anchor used to anchor an attachment shall be designed for one-half of the design strength defined herein.
For any of the cable tray support designs employing a single expansion anchor connection, this code provision would require a major reduction in the expansion anchor capacity.
TU Electric Comanche Peak Steam Electric Station L
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05/08/87 Revision 13 Page 13 CABLE 1 RAY SUPPGtT5 Review Issues List Cygna believes that the philosophy of the entire code appendix should be considered, rather than employing selected portions of the code.
D.
Factor of Safety on Richmond Inserts Gibbs & Hill's cele tray support designs employed a safety factor of 3.0 for Richmond Inserts for the 1/2 SSE load level. As discussed in Issue 1, the 1/2 SSE event was assumed to govern the support designs, without consideration of the reduced factor of safety on Richmond Inserts for the SSE event.
The safety factor for the SSE event will range from 1.8 to 2.0, depending on the building and elevation. See Item C, e ove, for a discussion of ACI 349-76 as it has been applied to Richmond Inserts.
E.
Richmond Insert Design 1.
Prying action was not considered in the original design of Richmond Insert connections for cele tray supports. To qualify those connections which use Richmond Inserts, Gibbs & Hill performed calculations which reference the results of the i
Richmond Insert testing program performed at the CPSES Site.
(Reference 3.) These calculations showed that 1" diameter Richmond Inserts, originally l
designed with Ta = 10.1 kips and Va = 9.5 kips, were l
not the controlling anchorage type, but rather that l
the Hilti expansion anchors were the limiting i
case. Cygna has the following comments regarding these calculations:
o The calculations do not account for the m
instances where the allowele values for 1" diameter Richmond Inserts taken from Gibbs 8 l
i l
Hill Specification 2323-55-30 (Ta = Va = 11.5 i
kips) may have been used without the prying
}
factor. This situation could occur whenever a TU Electric Comanche Peak Steam Electric Station I
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05/08/87 Revision 13 Pa ge 14 CABLE 1 RAY SUPMRTS Review Issues List new design was performed after the issue of this specification or a CMC /DCA allowed a change which affected the Richmond Inserts used in a support installation. Although Gibbs
& Hill has stated that their engineers were instructed to include the prying factor, Cygna could not locate any supporting documentation, o
Cygna has concerns on the use of the site testing of Richmond Inserts to justify higher allowable loads than considered in the original design. See Pipe Support Review Issues List Item 3, for additional detail.
2.
The original design calculations for concrete connections using Richmond Inserts employed allowable values of tension (Ta = 10.1 k) and shear (Va = 9.5 kips). With the issuance of Gibbs & Hill Specification 2323-5S-30, restrictions were placed on certain Richmond Insert allowables.
Decreases in allowable tensions and shears were provided for Richmond Inserts in cluster arrangements, Richmond Inserts enbedded in the sides of concrete beams, and Richmond Inserts used in spacings less than those originally considered in Gibbs & Hill designs.
Since these restrictions were imposed after the original design of the Richmond Insert connections was completed, Cygna is concerned that cable tray supports installed using Richmond Insert clusters or Richmond Inserts in the sides of concrete beams may not have been evaluated for the required reduction in allowables.
In discussions with TUGCO, Cygna was told that the Rich?3nd Inserts in clusters were reserved for pipe whip rastraints. Authorization to attach to these clusters should have been obtained from the responsible TUGC0 group, and a corresponding i
evaluation of the installation should have been TU Electric Comanche Peak Steam Electric Station b
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However, Cypa could not locate any TUSCO Quality Control instructions or procedures regarding the use of these Richnend Insert clusters (Reference 10).
F.
Connection Desips 1.
The cable tray support desips use angles or plates at base connections. The design drawings and associated design change documents (i.e., CMC /DCAs) specify anchor bolt spacing and member placement tolerances. However, these tolerances may be outside the original design limits. Gibbs & Hill I
has not fully evaluated the effects of all possible installation tolerances on the base member stresses or the anchorages.
Cygna's Phase 2 (bservations CTS-00-05 and CTS-00-07 respectively addressed the design of base connections for Detail "E" supports with three-directional loadings and Details "A-D" base plate designs (drawing number 2323-El-0601-01-5).
These support connection designs must also be reviewed to assure that the above concerns are addressed. For several additional support types considered in Cygna's Phase 4 review, the installation tolerances allowed by the design drawings were not considered in the design calculations.
2.
For most support types, the design drawings allow the use of either Hilti expansion anchors or Richmond Inserts for their anchorage to the concrete. For support types A, A e2 A 3
2 5)4, 0, D '
Detail "A" (Draving 2323-El-07 and Detail 11 (Drawing 2323-5-0905), the design calculations evaluate the attachments for Hilti expansion anchors, but not for Richmond Inserts.
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Justification of Prying Factor In response to Reference ll, Gibbs & Hill support designers used a factor of 1.5 to account for the effects of base angle / plate flexibility on anchor bolt tensile loads. The value of this factor is dependent on the applied load, bolt pattern geometry, and angle thickness. Justification for the use of this factor has not been provided.
5 H.
Anchor Bolt Sestitutions for Detail 1/1H and Details B, C and D For Detail 1H (Gibbs & Hill Drawing 2323-S-0909),
" Hanger Connection Using Hilti Bolts for Regular Cele Tray Supports," a s@ stitution of Richmond Inserts for Hilti expansion anchors is allowed by Note 14d (Gibbs &
Hill Drawing 2323-S-0901):
Detail "1H" (Drawing 2323-5-0909) Any Hilti bolt may be s@stituted with existing 1" diameter or 1-1/2" Richmond Insert except for i
the 1-1/4" x 13-1/8" Super Kwik 4olt which may be sestituted only with 1-1/2" diameter Richmond Insert.
l Additional information on the allowable bolt l
s@stitutions are provided in DCA 2103, Revision 0:
Question: When only one Richmond Insert is availele for a two4olt hanger connection, I
may a coe ination of one Richmond Insert and L
one Hilti bolt be used?
If so, what is the ll ~
minimum and maximum distance between the t
bolts, and what is the al',wele tolerance?
l Answer: Yes, cosinations'of Richmond Inserts and Hilti Super Kwik 4olts may be used.
j Minimum and maximum spacing between bolts b
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shall be the same as used for the "a" dimension shown in " Detail 1H, Two Bolt Hanger Connection," and the "a" and %" dimensions shown in "Two Bolt Beam Connection."
Tolerances shall be as shown in " Detail 1H,"
and in "Two Bolt Beam Connection."
t The DCA expands the scope of the s@ stitution to include the "Two Bolt Beam Connection" (Details B, C and D on Gibbs & Hill Drawing 2323-S-0903), and does not include the restriction on the use of a 1-1/2" diameter Richmond Insert as a s@stitute for the 1-1/4" x 13-1/8" Hilti Super Kwik 4olts.
These s@stitutions are inconsistent with several i
aspects of the c&le tray support design calculations.
)
The minimum bolt spacings are 12",15" and 16" for 1" diameter Hilti Kwik 4olts,1-1/4" diameter Hilti Super l
Kwik 4 olts, and 1" diameter Richmond Inserts, I
respecti vely. The tolerances specified for the 1
l connections esploying only Hilti expansion anchors are l
different from the tolerances for the equivalent connection detail employing only Richmond Inserts. For moment loads on the base connections, the tensile load in each anchor is calculated by dividing the applied moment by the minimum bolt spacing. The tensile load distribution due to direct pullout is calculated based on the allowed connection eccentricity. By s@ stituting t
a Richabnd Insert for a Hilti expansion anchor at the Hilti spacing and eccentricity, the tensile load in the Richmond Insert may be greater than the previously calculated load. The effect of this substitution on Richmond Insert tensile loads has not been considered in l
the cable tray support designs.
In addition, since L
DCA 2103 does not limit the size of the Richmond Insert to be s@stituted for a 1-1/4" x 13-1/8" Hilti Super Kwik 4olt in the beam connection, a 1" Richmond Insert, wMch has a lower capacity than the indicated Kwikeolt, could be used as a s@stitute.
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l Gibbs & H111/TUGC0 was not' able to provide the design verification documentation for DCA 2103 (Reference 13).
I.
Base Angle Boundary Condition Assumptions For trapeze type supports, Gibbs & Hill has assumed that 1
the hanger connections employing two4)olt base angles are free to rotate d)out the strong axis of the hanger. Since both the welds between the hanger and its base angle and the base angle itself have significant flexural stiffness, this assumption requires that the connection allow the calculated rotation without base i
connection failure.
Gibbs & Hill has not justified such connection behavior.
(See Review Issue 26)
J.
Installation of Expansion Anchors in Diamond Cored Holes Section 3.1.4.2.3 of Reference 4 discusses the reinstallation of an expansion bolt in an empty but
" pre-used" hole.
Paragraph (a) of that section states:
The bolt being replaced has been removed from the concrete using a diamond core bit of the same nominal outside diameter as the replacement expansion bolt. The replacement bolt shall be one diameter size larger than-the bolt being removed.
The Hilti " Architects and Engineers Design Manual" (Reference 5) addresses the bit type used in drilling holes for Hilti Kwik 4olts and Super Kwik 4olts. On page C-4, Note 6a states:
All of the technical information pertaining to KwikWbolts herein (e.g., pullout and shear data) was accomplished using HILTI ansonry caH)ide bits. Before installing the Kwik-bolt using another means of drilling (e.g., diamond a
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CABLE 1 RAY SUPMRTS Review Issues List Core), contact your. local HILTI Field Engineer for advice and proper procedures.
On page C-1 (Reference 5) a footnote to the installation process description states:
To obtain maximum p411shed holding values.-
use only HILTI carbide bits.
In discussions with Hilti, Inc., Cygna learned that Hilti expansion anchors installed in dianond core bored-holes will provide ultimate strengths that are less than those pelished in the Hilti Design Manual.
Primarily, the strength reduction is due to the diameter of the -
core bore bit itself.
It has been Hilti's experience that core bore bits are intentionally supplied at a larger diameter than the nominal size to account for the progressive reduction in bit diameter over its life.
Thus, at the initial bit usage, the bit diameter will be larger than that required for the bolt hole.
It is this hole oversize which causes the reduction in expansion anchor capacity.
In order to avoid any such strength reductions, careful control on the bolt hole diameter must be established.
Control may be established by measuring the core bit diameter or the hole diameter.
Cygna has not observed any QC procedures which impose such control.
Additionally, Cygna did not observe any procedures which require craft or QC to document which expansion bolts were installed in diamond cored holes.
K.
Reduced Allowable Loads for 1* Diameter Hilti Kwik-bolts Based on expansion anchor capacity tests performed by Hilti Inc. in 1980, Hilti issued a letter giving reduced ultimate ccpacities for 1" diameter Kwik bolts.
In response to this letter TUGC0 issued a Significant Deficiency Analysis Report (SDAR)
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05/08/87 Revision - 13 Page 20 CABLE 1 RAY SUPPGtTS Review Issues List (Reference 6) to evaluate the effect of the reduced anchor bolt capacities for support installations at CPSES. The resolution of this SDAR was to accept all j
existing designs employing 1" diameter Kwik-bolts by allowing a reduced safety factor of 3.41, and require that all future design efforts use the reduced capacity. The US NtC accepted this resolution (Reference 8).
For the review of cable tray supports where the cable tray load with Thermo-Lag exceeds the design load, Reference 7, section 3.2.2.1, paragraph (b ) states:
All hangers shall then be evaluated for actual loads. During this evaluation, all pertinent design changes shall be taken into account.
Consideration shall be given to use of actual tolerances, weld undercut-undersize, 1" diameter Hilti' Kwik-bolt revised criteria and actual field 'as built' configuration
.However, Cygna's review of the stject Gibbs & Hill calculations and a discussion with TUGC0/Gibbs & Hill (Reference 9), verified that the original (unrevised)
Hilti Kwik-bolt allowables had been used.
TUGC0/Gibbs &
Hill felt that the use of the original allowables was warranted, since.the calculations reviewed an existing desi gn. This is not consistent with the requirements of Reference 7.
Response
A.
Impe11 and Ibasco have performed studies to determine the magnitude of the effect of the eccentric loading on base plates and base angles. These studies were per-formed using finite eleme nt nodels of typical anchorage configurations and accourted for both the effects of eccentric loading and of plate fletility (i.e. prying action). The studies are contained in Reference 16 and summarized in Attachments G1 through G6 of Reference 15 and Attachments A and F of Reference 18.
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-05/08/87 Revision 13 Page 21 CABLE 1 RAY SUPMRTS Review Issues List Ebasco also performed a study, Reference 17, to evaluate the compressive stress in the concrete under the anchorage including the affects of shims under the anchorage.
For support anchorage configurations not addressed by the studies. Impell and Ebasco perform individual analyses using finite element models-of the specific anchorage detail.
B.
As discussed under Issue Ib.1, the cable tray support i
design verification evaluates each support for both OBE and SSE loading.
In accordance with Section IV.1.f.ii of Reference 14, Section 3.3.6 of Reference 19 and Sections 4.1.3 and 5.1 of Reference 18,. safety factors of 5.0 and 4.0 are used for Hilti expansion anchors for the OBE and SSE load cases, respectively.
C.
Per the discussion in Reference 29, the anchorage evalu-l ations performed for the design verification of cable tray supports do not explicitly reference ACI 349-76.
However, the development of the capacities for Richmond Inserts and enbedded plates may be based, in part, on ACI 349-80.
1 The validation of the Richmond Insert and enbedded plate I
capacities are under the jurisdiction of the Civil /
l Structural Action Plan portions being conducted by Stone i
and Webster Engineering Corporation (SWEC).
D.
The design verification of cable tray support anchorages i
use a factor of safety of 3.0 for Richmond Inserts for both the OBE and SSE load cases. The Richsond Insert capacities are presently being verified under the.
Civil / Structural Action Plan by SWEC.
E.
All cable tray support anchorages, including those using Richmond Inserts are individually design verified. As discussed under Issue No. 3.A. Ebasco and Impell have TU Electric Comanche Peak Steam Electric Station L
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Richmond Inserts capacities will be based on revision 2 of 2323-SS-30. The location of_ the insert (e.g. in column faces, sides of beams, clusters, etc.) will be considered. See Referenca 14,Section III.2, _IV.1.f.11 and Appendix 2 and Reference 18, Section 4.3.2 and Attachment B.
The Richmond Insert capacities are being verified by SWEC.
F.
The cd)1e tray support design verification evaluates the anchorages for each individual support. The use of 9eneric support anchorage details and the numerous design changes is no longer a concern. See Section III.2 of Reference 14 and Section 4.0 of Reference 18 for the Project requirements.
However, as discussed in Reference 29, B)asco evaluates certain supports by grouping like supports and analyzing an enveloping sup-port configuration. See issue No. 27_for a discussion of the support grouping techniques.
G.
The finite element models used in the base plate and base angle studies discussed in Issue No. 3.A provided justifications for the prying factors now used by the Project.
H.
In accordance with Section III.2 of Reference 14 and Section 4.0 of Reference 18, the design verification of support anchorage will be based on the as4)uilt support configurations. For supports which are fully acces-st)1e, anchor bolt sd>stitution is no longer of concern.
For supports which have inaccessible attributes (e.g.,
anchor bolts that are covered with thermalog, inacces-sibility due to congestion, etc.) the Project has not finalized the approach. See Issue No. 20.
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Ebasco and Impell' have performed finite element studies to develop the appropriate boundary conditions for use -
with the cable tray support nodelling.
Ebasco's study is documented in Reference 30 and i
summarized in Section III and Attachment 69 of
. Reference 15. All base plate / base angle configurations are assumed to be rigid for translational displacements and spring constants are developed for the three rotational displacements. The spring constants were developed for a large number of standard anchorage con-figurations, and Reference 15 requires that spring con-stants be developed individually for any support which does not conform to one of the standard configurations.
The Impell study is documented in Reference 31, and sum-marized in Section 3.2.5 of Reference 19.
Impell assumes that the anchorage is rigid for translational displacements and for rotations about the two geometric axes of the base angle. _ Spring constants were developed for rotation about the longitudinal axis of the base angle only. The stiffness values are only a function of the nunber of anchor bolts and the thickness of the base angle.
Unlike Ebasco, Impell does provide a large l.
nunber of stiffness values and does not require that spring constants be developed for non-standard anchorage configurations. This is discussed in Reference 28.
i J.
Impell provided a position paper (Reference 26) indi-l cating that if, at the time of expansion anchor instal-lation, the minimum set torque can be achieved, the i
installation of Hilti expansion anchors in diamond cored holes will have no impact on the ultimate capacity of i
the anchor bolt.
Based on communications between Cygna and Hilti, Inc.
(Reference 32), Cygna believes that the use of diamond cored holes will increase the variability in the anchor l
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K.
The cable tray support design verifications effort will use the reduced capacities for 1 inch diameter Hilti Kwik bolts. These values are specified in Appendix 2 of Reference 14 and Attachment B of Reference 18.
Status:
A.
Eccentricity between bolt pattern centroid and attach-ment point:
Open: Cygna is presently reviewing the studies. Cygna is also reviewing the methods used to analyze anchorage configurations which were not enveloped by the configu-rations chosen for the studies.
Impell uses BASEPLATE II and Ebasco uses P-DELTA STRUDL for individual appli-cations. Cygna has expressed concerns on the direction of the applied loading used for the individual baseplate analyses (References 28 and 29). Cygna has questioned the effect of shims on the results of the studies performed by Ebasco and Impell, and as such Cygna is reviewing the grouting and shiming procedures provided by TU Electric.
Richmond Insert allowables, prying action, cluster allowables and SS-30 restrictions:
Open: Stone & Wsster (SWEC) has reviewed the results of the site tests for Richmond Insert tension and shear i
values in order to validate the values p@lished in specification 2323-SS-30.
Additional work is presently being performed on cluster arrangements.
Prying action is considered by Ebasco and Impell for the support design verification.
)
Justification for Prying factor 1.5:
Open:
Impell and Ebasco have performed studies to determine appropriate prying factors.
Factors in some TU Electric Comanche Peak Steam Electric Station L
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Hill. Cygna is reviewing these studies.
Base angle boundary conditions:
Open: Impe11 and Ebasco have performed separate studies to determine appropriate boundary condition (trans-lational and rotational stiffnesses) for use in support models. The results are different for both consultants.
Cygna is currently evaluating the effect of the differ-ences on the analyses.
B.
Closed.
C.
Open pending review of the results of the Civil /
Structural Action Plan being implemented and managed by SWEC.
D.
Open pending review of the results of the Civil /
Structural Action Plan being implemented and managed by SWEC.
E.
Open: See Issue Pb. 3.A for the status of the review of the studies which determine prying action factors. See Issue No. 3.D. for the status of the review of the Richmond Insert testing program.
F.
Open:
Generic designs are no longer used.
However, see Issue No. 27 for the status regarding Ebasco's support grouping method which affects this issue.
G.
See Issue No. 3.A for status.
)
H.
Closed for all supports which are accessible. See Issue ib. 20 for the status regarding supports with inacces-sible attributes.
I.
Open: See Issue No. 3.A for status.
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Open.
K. ' Closed.
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4.
Design of Compression Menbers
References:
1.
Gibbs & Hill Calculation Binder 2323-SCS-1010 Set 1 2.
Gibbs & Hill Calculation Binder 2323-SCS-215C, Sets 2-6 3.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tray Support Review Questions," 84056.022, dated August 17, 1984, question 4 4.
Timoshenko and Gere, " Theory of Elastic Stability," 2nd Edition, pages 99 and 100 5.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tray Support Review Questions," 84056.041, dated Feb ruary 12, 1985 6.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analyses for Comanche Peak SES Nos. I and 2",
Revision 4 i
7.
Ebasco Calculation, " Comanche Peak SES Cable Tray Hanger Volume I", Book 6. " Buckling Study". Revision 1 8.
Impell Report No. 01-0210-1470, " Effective-Length l
Factors or Buckling of Cable Tray Supports", Revision 1 l
9.
Impell Report %. 09-0210-0018 " Slenderness Ratio Limits for CPSES Cable Tray Supports", Revision 0 10.
Ebasco Procedure SAG.CP.09, " Instructions for l
Re-Evaluation of Cable Tray Hangers Affected by the Longitudinal Tie of Transverse Hangers to the Tray",
Revision 0 11.
NCIG-01, " Visual Weld Acceptance Criteria", Revision 2 TU Electric l
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- 12. Ebasco Calculation, " Comanche Peak SES Cele Tray Hanger Volume I", Book-16. "CTH Dimensional Tolerances",
Revision 1
- 13. !basco Procedures SAG.CP4, " Seismic Design Criteria for Cable. Tray Hangers for CPSES Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for. Cable Tray Hangers for CPSES Unit 2", Revision 6 14.
Igell Instruction PI-03, " Qualification of Cable Tray Supports", Revision 4 15.
Igell Instruction PI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 16.
Impell Report 09-0210-0017. "CPSES Cable Tray System Analysis / Test Correlations, Revision 0
- 17. Communications Report between S. Harrison, J. Muffett (TU Electric); P. Harrison (Ebasco); R. Wheaton, B.
Ramsey (Impell); and N. Williams, S. Tunninelli, D.
Leong, J. Russ, W. Horstman (Cygna), dated March 6,.
1997,11:30 a.m.
- 18. Transcripts of Cable Tray Hanger Design Verifications Meeting between TV Electric, Cygna, Ebasco and Impell held at the CPSE site on 1/26 and 1/27/87 Summary:
A.
Compression Menbers with Slenderness Ratios in Excess of 200 In the design of cogression menbers for trapeze type support frames, Gibbs & Hill did not consider the entire unsupported length of the channels to calculate the slenderness ratios (Reference kSheets 11 and 18 for 4 and 8, respectiwely).
If the correct I
support types A 4
unsupported lengths and pinned end conditions are assumed, the slenderness ratio of these menbers for bending about their weak axis will exceed 200. AISC TU Electric Comanche Peak Steam Electric Station i
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8 Consideration of -In-plane Sidesway In calculating the slenderness ratio of the compression menbers for trapeze-type supports, Gibbs & Hill did not check the effectiveness of the in-plane sidesway restraint for the various support designs..This is discussed in Section 1.8 of the Commentary to the AISC Specifications.
C.
Unsupported Lengths and Effective Length Factors for Cantilever Type Supports In the design of the compression menber for cantilever type supports (e.g., SP-7, Details E F, G, and H on Drawing 2323-El-0601-01-S, etc. ) Gibbs & Hill used the distance from the face of the concrete to the centerline of the cable tray as the cantilever length. The correct length should be from the concrete face to the clamp in the far side of the tray.
A value of k = 1.0 was used to calculate the minor axis i
slenderness ratio, rather than the value of k = 2.0 for cantilevers. A value of k = 1.0 is based on the j
assumption that the tray will provide lateral bracing at the clamp location.
l-D.
Effect of Weld Undercut in Regions of Maximum Compression For the trapeze type supports, Gibbs & Hill has not considered the effect of weld undercut on the section properties of cogression menbers at the point where in-plane braces are attached to the channel wtb. As shown in the Working Point Deviation Study (Refert:oce 2), high stresses exist in the region of the brace attachment and may increase if the reduced section properties are considered.
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E.
Effect of Out-of-Pluabness on Compression Nunbers The design of compression menbers assumed that'.the applied axial load was parallel to the menber axis.
Gibbs & Hill Installation Specifications 2323-SS-Itb allows an installation tolerance of 2 degrees from plunb for vertical menbers. Cygna was unable to locate calculations considering the effect of this tolerance.
See Reference 5 for a discussion of this issue.
F.
Reduction in Unsupported Length of Compression Menbers i
Due to Outstanding Leg of Base Angle For trapeze type supports in the Working Point Deviation Study (Reference 2), Gibbs & Hill reduced the unsupported length of the hangers by 5".
This appears to be due to an assumption that the outstanding leg of the L5x5x3/4 base angle is rigid with respect to the-C6x8.2 hanger. However, the minor axis moment of inertia for the C6x8.2 is greater than the corresponding moment of inertia for the L5x5x3/4; therefore, the buckling hinge would occur within the base angle rather l
than at a point in the hanger below the base angle, and the reduction in unsupported length is unwarranted.
G.
Consideration of the Allowed Range of Brace Slopes For the design of braces in compression, the axial force is a function of the brace slope.
Gibbs & Hill designs provide a range of allowable brace slopes.
In some cases, Gibbs & Hill calculations check the brace for the slope which results in the largest axial load without a
considering other cases which have lower loads, but also have reduced capacity due to a longer menber length.
[
Response
A.
The design verification of compression menbers uses the entire member length. This is in accordance with Ebasco 1
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Review Issues List criteria (Reference 6. Attachment E) and Impe11 criteria (Reference 14).
Studies were performed by Ebasco (Reference 7) and Impe11 (Reference 8) to determine the appropriate effective length factors (k) for typical cable tray support meter configurations. These k factors are used in conjunction with the unsupported meter lengths to calculate the met er slenderness ratios.
In the development of the k-factors - Impell assumes that the cable trays provide a bracing to the cable tray l
support to prevent out-of-plane translation of the supports. Due to friction between the cable tray and l
the support components Impell feels that friction is j
justified based on the results of the cable tray system j
testing program (Reference 16). See Issue 710. 18 for a discussion of tray clamp behavior.
(
In Ibasco's development of k-factors..no. friction j
between the trays and clamps is assumed. The calculated k-factors are generally larger than those used by Impe11.
However, Reference 6 includes two sets of k-factors, those based on Ebasco's studies without friction and those based on Igell's studies with friction.
I The AISC has provided an interpretation clarifying the l
definition of " compression met ers" and " tension mem-l bers" as used in Section 1.8.4 of the AISC Specifi-cations. Met ers satisfying the definition of compres-sion met ers must satisfy a slenderness ratio of 200 and other limits on meter compressive stress levels.
l Tension meter slenderness ratios are limited to 300.
This is documented in Reference 9.
l B.
The design verification of cable tray supports do not consider the effects of in-plane sidesway in calculating the slenderness ratios for the cogression meters.
Ebasco and Impell have indicated (Reference 18) that for TU Electric Comanche Peak Steam Electric Station L
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the typical trapeze support, in-plane sidesway is associated with the major axis of the vertical channels while the out-of-plane buckling is associated with the minor axis. Since the minor axis slenderness ratio typically governs, there is no need to consider in-plane sidesway.
Ebasco, in Reference 6 requires the use of k = 1.0 for in-plane buckling of trapeze type support menbers and i
k = 2.0 for cantilevered supports and both components of L-shaped supports.
Impell provides similar requirements in Section 4.1.3 of Reference 14.
C.
In accordance with Reference 14, Section 4.1.3, Inge11 uses the distance from the face of the concrete to the outermost clamp location for the unsupported length. A value of K = 2.1 is used for buckling perpendicular to the tray. For buckling parallel to the tray, bracing from the tray is assumed and the k-factors developed in Reference 8 are used. The assumed bracing provided by i
the tray is justified in Reference 16.
Reference 6 Attachment E, provides Ebasco's criteria for the buckling of cantilever type supports. The calculation of the unsupported length is based on the type of tray clamps used. The unsupported length is equal to the distance from the face of the concrete to the clamp which will transmit compressive axial load. A value of k = 2.0 is used for buckling about each axis.
l However, Paragraph 10 of Attachment E allows the considecation of connectivity between the tray and the support in the tray axial direction and permits the use of the k-factors developed by Impell for minor axis b uckling.
D.
Since the supports will be individually evaluated based on the as-built support configuration, weld undercut does not have to be considered on a generic basis. The i
project is performing weld inspections in accordance
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If the welds satisfy the undercut limitations given in Reference 11, undercut will not be considered in the analyses, otherwise the weld will be repaired. Therefore, there is no need to consider weld-undercut in the regions of maximum compression.
E.
Only menbers that are greater than two degrees out-of-plunb are to be individually evaluated.
If a menber is less than or equal to two degrees out-of-plunb, any effects on the menber are considered negligible.
This
-is based on a study performed by Ebasco (Reference 12) and the results of the cable tray system testing (Reference 16). Ebasco's requirements are given in Attachment E of Reference 6 and Impell's requirements are given in Reference 15. Section 3.2.1.
F.
The entire menber length, measured from the face of the concrete, will be used by both Ebasco and Impell in calculating the unsupported menber length.
Eb asco 's procedure is contained in Reference 6, Attachment E.
Impell's procedure is noted in Reference 15 Section 3.2, Reference 14, Section 4.0 and Reference 8.
l G.
This is no longer an issue. The design verification is j
based on the as4u11t configurations of all supports.
l Therefore, actual brace slopes are used without the need to consider the range of slopes allowed by the original design.
Status:
A.
Open: Detailed reviews of the k-factor studies and test results are required. As discussed in Reference 17, Cygna is concerned about the application of the results I
of the k-factor studies to support configurations not addressed in the studies..
B.
Open: This issue was discussed in Reference 17. Cygna is concerned about the use of k = 1.0 for in-plane sidesway of longitudinal trapeze type supports (e.g.
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4 oriented so.that their minor axis is associated with in-plane sidesway.
The use of k = 1.0 also affects the calculation of F'e used in AISC equation 1.6 - la to consider the moment magnification effect.
C.
Open: Detailed review of the k-factor studies and test results are required.
D.
Open: Cygna is reviewing Reference 11 for acceptability.
E.
Open: Cygna will review References 12 and 16 for acceptability.
The effect of this must be considered in the cumulative effects evaluation which is under Issue No. 29.
F.
Closed.
G.
Closed.
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Vertical and Transverse Loading on Longitudinal Type Supports
References:
1.
Gibbs & Hill Calculation Binder 2323-SCS-101C Set 2 2.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
i
" Cable Tray Support Review Questions," 84056.025, dated August 21, 1984, questions 3 and 4 3.
R.E. Ballard (Gibbs & Hill) letter to N.H. Williams 4
(Cygna), GTN-69437, dated Septenber 10, 1984, with attached calculations
(
i 4.
Gibbs & Hill Calculation Binder 2323-SCS-101C, Set 5 5.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for CPSES Nos. I and 2", Revision 4 i
6.
Ebasco Procedure SAG.CP11. " System Analysis for Cable Tray and Hanger Assenbly for CPSES, Units 1 & 2",
Revision 2 l
7.
Impell Instructions PI-02, " Dynamic Analysis of Cable l
Tray Systems", Revision 5 Summary:
Longitudinal trapeze type supports (e.g., L-A, L-A, L-C,
3 4
4 etc.) were assumed to act independently of the transverse supports (see Reference 4). Calculations for these longitudinal supports (Reference 1) only considered longitudinal cable tray loads in the design of frame menbers and anchor bolts. Since these supports are rigidly connected to the cable trays with " heavy duty clanps," a tributary tray mass will be associated with these supports.
Given this type of tray connection, Cygna has questioned whether the.e supports must be additionally designed for i
vertical and possibly transverse seismic loads similar to i
the transvers supports (Ref6rences 2 and 3).
Response
The Ebasco and Well cable tray support evaluations will consider the effe-ts of three dimensional loading on l
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05/08/87 Revision 13 Page 36 CABLE TRAY SUPPGtTS Review Issues List longitudinal trapeze supports. This is iglemented in Reference 6 and Attachments B2, Y and I of Reference 5 for Ebasco's evaluations and Section 3.3.5 of Reference 2 for Impell's evaluation.
Status:
Closed.
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. l 6.
Support Frame Dead and Inertial Loads
References:
1.
Gibbs & Hill Calculation Binder 2323-SCS-101C, Set 5, i
" Cable Tray Supports (Design Criteria and Reference)"
l 2.-
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for CPSES Nos. I and 2", Revision 4 3.
Impe11 Instruction PI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 4.
Impe11 Report. 09-0210-0017. "CPSES Cable Tray System Analysis / Test Correlation", Revision A 5.
Ebasco Procedure SAG.CP11. " System Analysis for Cable Tray and Hanger Assenbly for CPSES Units 1 & 2",
Revision 2 Summary:
A.
Out-of-plane Inertial Loads Out-of-plane inertial loads (i.e. loads in the direction parallel to the cable tray) were not considered in the design of two-way cable tray supports. Such loads-should. -as a minimum, be considered in the design of I
base connections and anchorages. Assuming that tray j
clamps are able to transmit the loads from the two-way I
supports to the cable trays, out-of-plane inertial loads l
from the two-way supports must also be considered in the l'
menber and anchorage design of longitudinal supports.
(See Review Issue 18.) _
B.
Support Dead Weight l
Gibbs & Hill did not consistently consider support dead i
- 1. ads. The support design calculations considered j
c@ port weight in one of the following ways:
l (a) The support weight was not considered.
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a 05/08/87 Revision 13 Page 38 CABLE 1 RAY SUPPGt15 Review Issues List 1-(b) The support weight was considered as a surcharge on 2
the tray, in addition to the tray and cable weight.
Usually, this value was given as 5 psf.
(c) The support weight was calculated by considering the actual weight of each of the support's frame menb ers.
(d) A dead load equal _ to one half the support weight was i-used as required by Reference 1. Sheet 3.
l Method (b) also led to other problems in the support design.
Initially, the tray unit weight was considered as 35 psf. When the " effective" support weight of 5 psf was added to the cable tray unit weight the result was a total assumed tray desi,gn load of 40 psf. At a later point in time, when design changes were issued against the supports or a revised analysis was. required, the designer reduced the design weight from 40 psf to i
37.5 psf. or even 35 psf, to remove some " conservatism" from the design loads in order to qualify the support.
By doing so, the designer removed a portion of the support weight.
Response
A.
The dynamic testing of cable tray system models, as discussed in Reference 4, has demonstrated that friction type clamps will prevent relative displacement between the supports and the cable trays in the tray axial direction. This effect could allow for the transfer of a portion of the out-of-plane inertial loads for a transverse support to a longitudinal support elsewhere in the cable tray system.
(See Issue %.18).
The two consultants have taken different approaches to the resolution of this issue. For the static and equivalent static analysis of transverse cable tray supports, Ibasco does not assume connectivity between the tray and the support for the transfer of out-of-plane loads.
This assumption is noted in l
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Thus, the out-of-plane inertial loads are resisted solely by the transverse support. For cases where the support evaluation is performed using the response spectrum method, as discussed in Reference 5, connectivity between the tray and any transverse support is not i
considered.
However, a sufficient number of analyses assuming connectivity are to be run to show that the assumption of no connectivity is conservative.
Impell performs the cable tray support evaluations using system models and response spectrum analyses.
In accordance with Reference 3, seismic loading is applied simultaneously in three orthogonal directions, thus i
accounting for the out-of-plane inertial loading.
Impell's analyses consider connectivity between the transverse supports and the tray, hence, the
+
out-of-plane inertial loads on the support are shared between the support under consideration and the lo_ngitudinal supports elsewhere in the cable tray system.
When modelling the cable tray supports. Impell provides nodes at load application points, member connection l
points, and at intermediate points within an individual menber's length. Ebasco provides nodes only at load application and menber connection points.
8.
The dead weight of the support menbers is included in the support models, both for the equivalent static analysis and response spectrum analysis methods. This is specified in Attachments 81, 82, Y and Z of Reference 2 and Reference 5 for Ebasco and in Section 3.3.2 of Reference 3 for Impe11.
Status:
A.
Open: Cygna has concerns regarding Ebasco's node point placements, especially in brace menbers.
If a sufficient nusber of node points are not included, the dynamic response cannot properly be predicted.
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d 05/08/87 Revision 13 Page 40 CABLE 1 RAY SUPPGtTS Review Issues List Therefore, the flexure of the braces caused by inertial effects will be underpredicted. See Issue No.18 for a discussion of Cygna's concerns relative to damp b ehavior.
B.
Open: Since Ibasco has not modelled node points in the interior of members, flexure due to dead weight will be i gnored.
)
4 a
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Review Issues List 7.
Design of Angle Braces Neglecting Loading Eccentricity i
References:
1.
N.H. Williams (Cygna) letter to J.B. George '(TUGCO),
" Cable Tray Support Review Questions," 84056.025, dated August 21, 1984, questions 3 and 4 2.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tray Support Review Questions," 84056.027, dated August 27, 1984, question 2 3.
AISC, " Specifications for the. Design, Fabrication and Erection of Structural Steel for Buildings", 7th Edition, Sections 1.15.2 and 1.18.2.4 4
Gibbs & Hill Calculation " Cable Tray Support Type SP-7 With Brace. Brace Eccentricity Calculations." Cygna Technical File 84056.11-1.228
- 5.. Gibbs & Hill Calculation " Verity the Adequacy of Brace L3x3x3/8 of the Governing Support Case C." Gibb s &
3 Hill Calculation Binder 2323-5C5-101C.
Set 1, Revision 1 dated 11/16/84 6.
Gibbs & Hill Calculation " Justify the Use of Two L3-1/2 x 3-1/2 x 3/8 Angles to Take the Appropriate Load l
and Moment Individually in the Longitudinal Tray Supports at the Lower Brace." Gibbs & Hill Calculation Binder 2323-SCS-1010, Set 2 Revision 6. dated 9/15/84 1
7.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for CPSES no. I and 2", Revision 4 8.
Igell calculations M-12 " Qualification Procedure for Cable Tray Support Evaluations", Revision 2 l
l 9.
Igell Instruction PI-03, " Qualification of C:ble Tray l
Support", Revision 4 I
l.
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05/08/87 Revision 13 Page 42 CABLE 1 RAY SUPPGt15 Review Issues List 10.
Impe11 Instruction PI-02, " Dynamic Analysis of Cable Tray Systems" Revision 5
- 11. Transcripts of Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna. Ebasco and Impe11 held at the CPSES site on January 26 and 27,1987
- 12. Communications Report between S. Harrison, J. Muffett (TV Electric); P. Harrison (Ebasco); R. Wheaton, B.
Ramsey (Impell); and N. Williams, S. Tumminelli, D.
Leong, J. Russ W. Horstman (Cygna), dated March 6, 1987, 11:30 a.m.
Summary:
A.
Dosle Angle Braces Longitudinal cable tray supports frequently use dosle angle sections as bracing to resist the longitudinal loads (e.g., L-A, L-B, etc). For the menber design, 4
4 4
loads were assumed to produce only axial stresses. The induced bending stresses due to the eccentric. end connections were not considered.
Neglecting these flexural stresses can result in menbers which are under-designed. The design of the dosle angles assume that the angles behave as a composite menber.
- However, t
no intermittent filler plates are provided as required j
by the AISC Specification, Section 1.18.2.4 Thus, the l
dosle angles must be considered to act independently.
See Issue No.14.0.
l B.
Single Angle Braces Transverse and longitudinal cab 1r. tray supports typically use angle sections as N-plane braces to i
resist transverse loads and provide bracing points on the vertical menbers (e.g., A, A, 8, 8, L-A, etc) 3 4
3 4
4 and for longitudinal bracing on some support types (e.g., L-A., SP-7 with b race, etc. ).
For the menber design, loads were assumed to produce only axial stresses. The induced bending stresses due to eccentric TU Electric Comanche Peak Steam Electric Station A
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end conditions were not considered. Though it is not explicitly stated in the AISC Specifications, it is standard practice (Reference 3 Sheet 3-59) to consider the bending stresses due to end connection eccentricity-and check the interaction ratio considering the principal axes section moduli.
1 C.
Twist Buckling
(
Single angle longitudinal braces are typically connected to the support frame by welding along the legs of the angle. Some brace designs provide welding on only one angle leg at one end of the brace; while, at the other end of the brace, welding is provided on the opposite angle leg. Such end conditions may lead to failure by twist buckling at load levels below the critical value for Euler buckling. Twist buckling may. also be a i
concern for angles which are supported by welding on the same leg at each end.
Response
A.
In Reference 7. Attachment E and Reference 10 Section 3.2.3, it is required that filler plate spacing be checked in accordance with Section 1.18.2.4 of the l
A!SC Specification.
If these requirements are not satisfied, composite action will-not be assumed.
Further, Cygna's audit indicates that Impe11 l
conservatively includes only one of the two angles 'in the support model when the requirements of Section 1.18.2.4 are not met for dotble angles.
B.
In accordance with Reference 7, Ebasco models all angle sections as pin ended (truss) members. The effect of the eccentric loading on the braces is considered by applying a bending moment to the end of the brace which is equal to the calculated axial load multiplied by the l
connection eccentricity. This is done using hand l
calculations performed after the finite element analysis l
has been completed. The bending moment is resolved into l
two conponents relative to the angle section's principal
(
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Review Issues List axes and bending stresses are calculated in accordance with Reference 3, sheet 3-59.
Ehasco us.es 0.6 Fy for the flexural allowable. The determination of the axial allowable was performed in Attachment V of Reference 7.
See Section C of this issue for further discussion.
Igell models brace menbers using beam elements and i
ignoring connection eccentricities.
Impell performed a study (Reference 8. Appendix B) which showed that neglecting the connection eccentricities was more conservative for the brace. Additionally, the study V
concluded that proper end condition assumptions for the a
brace were important to obtain the proper response.
In L
the case where the brace menber was welded to the back l
of the post menbers, the moments induced in the brace were significant. Similarly, the same would be true for 4
braces connected to gusset plates.
Impell considers l
moment fixity on all axes except that which would cause -
out-of-place displacement of the brace. The gusset plate configuration was not addressed by the Impe11 study..
In both the response prediction and stress evaluation, Impell uses the brace menber's geometric properties instead of.the principal axes properties. When performing the stress evaluation (Reference 9. Section 9), Igell multiplies the flexural stresses by a factor of 1.2 (Reference 8. Appendix F) to account for the use of geometric properties.
l l
Igell assumes a flexural allowable of 0.6 Fy. For the axial allowables controlled by Euler behavior, Impell uses the allowables for the AISC specification. For a discussion on Impell's approach to twist buckling of the L
angle sections, see Section C below.
C.
Ebasco provides a method for addressing twist buckling of angles in Attachment V of Reference 7.
Impell TV Electric l
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05/08/87 Revision.13 Page 45 CABLE 1 RAY SUPMRT5 Review Issues List provides another method in Section 4.1.3 of Reference 9.. A study in Reference' 8. Section 5.4 i
indicates that twist buckling will govern over Euler buckling.only for angle sizes which are larger than those typically used for cable tray supports.
- However, this study bases' the determination of the governing buckling mode at a point where the twist buckling capacity exceeds 95% of the Euler buckling capacity.
Neither consultant's approach considers the case of twist buckling of angles attached at opposite legs at either end.
In Reference 12 Impell indicates that they would provide an evaluation of this loading confi guration..
Status:
A.
Open: See Status for Issue No. 7.B.
The response is satisfactory with respect to the use of filler plates.
B.
Open: B>asco's use of principal axes properties is acceptable. Cygna is reviewing the documentation provided by Impell on the allowd)le flexural stress for angles as well as the use of geometric axes properties. Additionally, Cygna is reviewing B)asco's use of truss elements with pin-ended connections and the allowdale flexural stress of 0.6 Fy.
C.
Open: Additional review of the methods used to evaluate twist buckling by both consultants is required.
Impell will provide an evaluation of twist buckling of angle sections attached at opposite legs.
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Dynamic Anglification Factors (DAF). Tributary Tray Support Reactions and Missing Mass Effects
References:
1.-
Gibbs & Hill Report, " Justification of the Equiva' lent Static-Load Method Using a Factor of 1.0 Times Peak Spectrum Acceleration for the Design of Cable Tray Supports; Comanche Peak Units 1 and 2" 2.
Communications Report between J. Jan (Gibbs & Hill), and G. Bjorkman (Cygna) dated October 4, 1984, 4:00 p.m.
3.
Communications Report between J. Jan, P. Huang, J. Pier -
(Gibbs & Hill); and N. Williams, G. Bjorkman (Cygna)
~
dated Septenber 13, 1984, 3:00 p.m.
)
4.
Communications Report between J. Jan, J. Pier (Gibbs &
Hill}, Fn:t G. Bjorkman (Cygna) dated October 12, 1984, 10:00 a.m.
5.
Consnunications Report between J. Jan (Gibbs & Hill); and G. Bjorkman (Cygna) dated October 18, 1984 6.
Consnunications Report between J. Jan, et al. (Gibbs &
Hill); and H. Levin (TERA); R. Kissinger, et al.
(TUGCO); N. Williams, et al. (Cygna) dated October 31, 1984 7.
CPSES, FSAR, Section 3.78.3.5 8.
Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 2", Revision 6 9.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for CPSES Nos. I and 2", Revision 4 t
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- 10. Ebasco Calculation, "CPSES Cable Tray Hanger Volume 1",
Books 9 & 10. "Multimode Response Multiplier Studies",
Revision 0
- 11. Ebasco Calculation, "CPSES Cable Tray Hanger Volume 1",
Book 15. " Cable Tray Dynamic load Redistribution Effects", Revision 1 12.
Igell Instructions PI-02, " Dynamic Analysis of Cable Tray Systems", Revision '5 4
- 13. Transcripts of Cable Tray Hanger Design Verification Meeting Between TU Electric, Cygna. Ebasco and Impe11 held at the CPSES site on January 26 and 27,1987
- 14. Conmiunications Report between B. Lashkari (JBA); J. Park (Igell); J. Christoudias, D. Fong, P. Harrison, R.
Alexandru, S.J. Chen, F. Hettinger, J. Swanson (Ebasco);
and W. Horstman, D. Leong, J. Russ, S. Tusminelli (Cygna), dated F&ruary 10, 1987, 8:30-5:00 p.m.
- 15. Communications Report between S. Harrison, J. Nandi (TV Electric); G. Ashley, B. Ramsey (Impe11); R. Alexandru, P. Harrison, S.J. Chen, and F. Hettingor (Ebasco); and N. Williams, W. Horstman, D. Leong, J. Russ, S.
j Tumminelli (Cygna), dated F&ruary 12,1987,10:00 a.m.
l l
Summary:
A.
Equivalent Static Analyses Gibbs & Hill performed cable tray support designs using an " equivalent static analysis" to account for seismic loads. The tray dead load on a support was calculated by the tributary span method. The tray seismic load was the product of the tray dead load and the peak spectral acceleration for the given buildings elevation. A TV Electric Comanche Peak Steam Electric Station
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05/08/87 Revision 13 Page 48 CABLE 1 RAY SUPP(RTS Review Issues List dynamic amplification factor (DAF) was not included as required by Reference 7.(see also Issue 25. A).
An additional factor to be considered is the ratio of the static reaction for a continuous beam to the reaction calculated by the tributary span method.
This ratio depends on the relative stiffness between the trays and supports, the relative stiffness between-different support types and the nunber of continuous 1
spans.
B.
Missing Mass Effects in Response Spectrum Analyses As discussed in Issue No.11 Gibbs & Hill performed several ~ generic studies for cable tray support qualification using cable tray system models and the response spectrum analyses method.
In general, Gibbs &
Hill did not check the analysis results for sufficient mass participation in the response spectrum analyses.
Response
A.
Impell performs all cable tray support qualifications using cable tray system models and the response spectrum analysis method. System models will accurately capture the support reactions for the continuously supported tray. A dynamic amplification factor is not required i
when performing response spectrum analyses.
Impell's approach is discussed in Reference 12.
Ebasco performs support qualifications using static, l
equivalent static, and response spectrum method.
The system models analyzed using the response spectrum analysis method are similar to those used by Impell and do not need to consider this issue as indicated above.
When performing support qualification by the static or equivalent static methods, Ibasco uses a multimode i
I response multiplier (m M) of 1.25.
The EM accounts for i
both the (ynamic anplifications and the support reactions for the continuously supported tray. The l
(
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B.
For all response spectrum analyses performed for cdale tray support qualification, a missing mass correction will be incorporated.
B)asco uses the missing mass option of P-Delta STRUDL and Impell uses the missing mass correction in SUPERPIPE. See References 13 and 14.
Status:
A.
Open: Based on a review of B)asco's MRM development study Cygna provided several questions to B)asco which will require further evaluation. See References 14 and 15 for details.
B.
Closed: Missing mass effects are being accounted for, t
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Page 50 CABLE 1 RAY SUPPGtT5 Review Issues List 9.
Reduction in Channel Section Properties Due to Clamp Bolt Ibles
References:
1.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tray and Conduit Support Review Questions,"
84056.015, dated August 6,1984, Attachment B, question 2 2.
Gibbs & Hill letter GTN-69371, dated 8/23/84,.
Calculation SCS-111C, Set 8, Sheets 34-39 i
3.
AISC " Specification for the Design, Fabrication and Erection of Structural Steel for Buildings", 7th Edition 4.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis of CPSES Nos.1 and 2", Revision 4 5.
Impell Instructions PI-11. " Cable Tray System Analysis and Qualification Closeout". Revision 1, with addendum dated 1/19/87 6.
Igell Instructions PI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 l
l 7.
Transcripts of Cable Tray Hanger Design Verification Meeting Between TU Electric, Cygna. Ebasco and Impell held at the CPSES site on January 26 and 27,1987 Summary:
The AISC Specification (Reference 3), Section 1.10.1 states:
Riveted and welded plate girders, cover-plated beams and rolled or welded beams shall in general be proportioned by the moment of inertia of the gross section.
Ib deduction shall be made for shop or fiel&' rivet or bolt holes in either flange, exce$h that in cases where the reduction of the area of either flange by such holes, calculated in accordance with the provisions of TU Electric Comanche Peak Steam Electric Station L
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Section 1.14.3, exceeds 15 percent of the gross flange area, the excess shall be deducted.
Cygna found instances where the areas of bolt holes, used for'the tray clasp bolts, exceeded 15 percent of the gross flange area, and the required reduction in moment of inertia had not been considered in the design calculations.
An evaluation of this issue should consider the following 4
items:
o Cable trays may be placed anywhere in the beam span (for example, see CMC 2646).
o The case for cantilevered supports where one tray is close to the wall and other trays are located further out from the wall.
o The effect of DCA 17838, which provides bolt hole gage tolerances, and allows the use of.3/4" diameter holes for 5/8" diameter bolts.
o All unused flange holes are not required to be plug-welded and may be present in high moment regions.
(See Note 15 on Gibbs & Hill Drawing 2323-5-0901, L
Revision 4.)
l
Response
The reduction in channel section properties due to bolt holes will be considered in the design verification of cable tray supports.
Impell considers the effect of a 3/4 inch diameter bolt hole located at the tip of the channel flange or at the actual hole location, if available, per Section 2.3.2 of Reference 5.
Used bolt holes will be identified on the as built c.?pport drawings.
Unused bolt holes are assumed to occur Li any location in the support.
The unused bolt hole must be assumed to occur in the area where its presence will cause maximum stress. The effect of TU Electric Comanche Peak Steam Electric Station b
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i the section reduction will only be considered if the
. interaction values exceed specified levels.
Ebasco follows a similar procedure to consider the effect of bolt holes, a~s required by Attachment E. Item 11, of Reference 4.
In Reference 7. Ebasco indicated that a sample of over 200 used bolt holes were reviewed to determine the maximum hole size present for the 5/8 inch diameter tray clamp bolts.
This sample indicated that the largest hole used is 3/4 inch diameter.
Ebasco will make the results of this review available to Cygna for audit.
Status:
Open: Cygna to audit Ebasco sampling of bolt hole diameters. Cygna also to review the criteria used in References 4 and 5 to determine when bolt holes must be considered.
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- 10. System Concept
References:
1.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tr.ay Support Review Questions," 84056.031, dated August 31, 1984, Attachment A, question 2 2.
L.M. Popplewell (TUGCO) letter to ' N.H. Williams (Cygna),
dated Septes er 28, 1984 with attached calculations 3.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for CPSES No.1 and 2", Revision 4 C
4.
Ebasco Procedure SAG.CP11. " System Analysis for Cable Tray and Hanger Assedly for CPSES Units 1 & 2",
Revision 2 5.
Ebasco Calculation, " Comanche Peak SES Cable Tray Hanger Volume I", Book 2; " Computer Related Information",
Revision 3 f
6.
Ebasco Calculation, " Comanche Peak SES Cable Tray Hanger Volume 1", Book 7: " Cable Tray Hanger Load Application Location Studies", Revision 1 7.
Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cable Tray Hangers' for CPSES Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 2", Revision 6 8.
Impell Instruction PI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 9.
Impell calculation M-12. " Qualification Procedure for Cable Tray Support Evaluations", Revision 2 10.
Impe11 Report OL-0210-1470, " Effective-Length Factors for Buckling of Cable Tray Supports", Revision 1 TU Electric Comanche Peak Steam Electric Station b
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11.
Impell Instruction PI-07, " Design Verification of Base-Plates, Base Angles, and Enbedded Plates". Revision 3 Summary:
In order to justify certain design assumptions questioned by Cygna (Reference.1), documentation was provided indicating that Gibbs & Hill had assumed that the cable tray and supports act as a system. (Reference 2.) As part of this
" systems" approach, the following behavior was assumed:
A.
Loading Eccenricities I
The moments introduced by the eccentricities between the load application points (i.e., tray centroid) and the c
menber centroid were balanced by load couples between adjacent supports. More specifically, for longitudinal supports (e.g., SP-7 with brace, Detail 8, drawing 2323-S-0903, etc.), the development of torsion in the beam due to longitudinal loading eccentricity is
[
prevented due to the development of flexure in the cable tray. This tray moment is stbsequently balanced by a vertical load coupled between adjacent supports.
Similarly, the torsion in the beam and the weak axis bending in the hanger due to the vertical load placement eccentricities as well as the bending moment in the beam due to the transverse load-placement eccentricities are all balanced by either vertical or transverse load couples between adjacent supports.
Such moment transfers as described above are only possible if full rotational and translational cogatibility exists between the cable tray and support b eam. The relative stiffness between the trays and j
their supports can also affect the percentage of the moment to be balanced by the load couples between l
supports.
Gibbs & Hill assumes that the compatibility
(
is provided by the heavy duty and friction types of tray clags. See Review Issue 18 for a discussion of Cygna's l
concerns regarding the clamp behavior.
l l
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Bracing for Compresion Menbers In the design of trapeze support hanger menbers for compression loads, the trays provide lateral bracing.at points along the length of the hanger. Similarly, for cantilever type supports, the tray provides lateral bracing to the beam.
(See Issue No. 4A.)
C.
Independence of Transverse and Longitudinal Supports l
For trapeze type supports, the longitudinal and transverse support systems act independently.
Therefore, the longitudinal supports are designed for longitudinal loads only, i.e., no transverse or vertical load contribution is considered.
(See Issue No. 5. )
D.
Base Angle Rotation Additional tensile forces introduced by rotation of the base angles about the bolt pattern axis is minimir.ed by the hanger attachment to the tray.
(See Issue No. 3A.)
E.
Out-of-Plane Inertial Loads For trapeze type supports, out-of-plane seismic inertial loads from two-way support frames (self-weight excitation) are resisted by the longitudinal supports.
However, as discussed in Review Issue 6, these inertial loads have not been considered in Gibbs & Hill's design of longitudinal supports.
F.
Menber Connection Eccentricities The cable tray supports use channel sections for the beam and hanger menbers. The typical connection between the beam and hanger is a lap joint, with the channels attached back-to back. This tyoe of connection will l -
f TU Electric Comanche Peak Steam Electric Station L
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(Reference 1 Question 2.2.)
Gibbs & Nill addressed this issue in Reference 2, indicating that a portion of the effect is resisted as additional loads in the cable tray, and the net effect on the stress level in the support is an increase of less than a three percent.
Response
A.
The design verification of cable tray hangers will include the effects of most eccentricities between the cable tray and the support menbers. See Issue Nos. 24. A. 24.B. 24.C. and 24.D. - See Issue 2. 18 regarding clamp behavior.
B.
See Issue No. 4.A for a discussion pertaining to the bracing for compression menbers.
C.
See Issue 2. 5 for a discussion pertaining to the treatment of longitudinal and transverse supports.
(
D.
See Issue it. 3. A for a discussion pertaining to the treatment of base angle rotation.
E.
See Issue No. 6. A regarding the treatment of out-of-plane inertial loads.
l F.
The effects of the eccentricities between menbers are l
considered in the design verification of the cable tray
(
supports.
In Reference 7 Section IV.1.a and Reference 3, Attachment E Ebasco specifies the methods to be used to account for connection eccentricities which are based on a study documented in Reference 6.
For a typical back-to back channel lap joint, the eccentricity is the distance between the center of gravity of one menber and j
the shear center of the other.
TU Electric i'
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05/08/87 Revision 13 Page 57 CABLE 1 RAY SUPP(RTS Review Issues List Impell,1 n Reference 8. Section 3.2.3 and Reference 9, 1
E specifies how the eccentricities will be considered.
The method used by Impell in modelling lapped joints is consistent with Ebasco's approach.
However,'.for other
. connection geometries Impell's approach differs from.
B) asco 's.
Status:
A.
See Issue Nos.18, 24. A. 24.B. 24.C. and 24.D.
B.
See Issue No. 4. A and 18.
C.
See Issue No. 5.
D.
See Issue No. 3. A.
E.
See Issue No. 6. A.
i F.
Open: Cygna has reviewed the eccentricities addressed by Impe11's and B)asco's procedures. Additionally, Cygna has performed audits of both consultants to i.
determine what eccentricities are modelled for configurations not addressed by the procedures.. Further.
review is required to validate the acceptability of the individual eccentricity requirements as well as any differences in the approaches used by the two consultants. Cygna will evaluate the effect of potentially individually insignificant eccentricities as a part of the ANCO test program review.
i l
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Validity of NASTRAN pbdels
References:
1.
Gibbs & Hill Calculation Binder 2323-SCS-215C, Sets 2-6 Gibbs & H'111 Calculation Binder 2323-SCS-101C, Set 3, 2.
Sheets 234-243, Revision 9 3.
Gibbs & Hill Calculation Binder DMI-13C, Set 1 4.
Gibbs & Hill Report, " Justification of the Equivalent Static Lead Method Using a Factor of 1.0 Times Peak Spectrum Acceleration for the Design of Cable Tray Supports; Comanche Peak Units 1 and 2".
5.
Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 2", Revision 2 6.
Impe11 Instructions PI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 Summary:
Cygna has questioned the validity of the NASTRAN models used in the Gibbs a Hill. generic studies, such as the Working Point Deviation Study (Reference 1), the qualification of Detail Di (References 2 and 3) and the Dynamic Amplification Factor Study. (Reference 4.) The analysis models consist of
(
identical supports, separated by equal spans. This modelling will influence the system frequencies and seismic response and may not be representative of an actual installation, where a mixture of support types, non-uniform spans and tees or elbows in the tray are used.
Response
The design verification for cable tray supports is based on the as-built support configurations and cable tray routing.
This is specified in Reference 5.Section III.2 TU Electric Comanche Peak Steam Electric Station L
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for Ibasco and Reference 6. Section 3.2.1 for Impell. The results of the Gibbs & Hill NASTRAN models will not be used.
The %namic aglification factor used by Ebasco is based on a study performed using a series of uniform supports at equal spacing. This study is similar to the evaluation performed by Gibbs & Hill. See Issue No. 8 for a discussion of this study.
Status:
. Closed for the original Gibbs & Hill NASTRAN models. See Issue Ib. 8 for the status of the dynamic amplification factor study performed by Ebasco.
il l.
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- 12. Working Point Deviation Study
References:
1.
Gibbs & Hill Calculation Binder 2323-SCS-215C Sets 2-6 2.
Gibbs & Hill Calculation Binder 2323-SCS-216C, Sets 1-5 3.
AISC, " Specification for the Design, Fabrication and erection of Structural Steel for Buildings", 7th edition 4.
Gibbs & Hill Report, " Cable Tray Raceway System Dynamic Analysis Program," March 19, 1985 5.
Comunications Report between M. Warner (B8R/TUGC0 QC) and W. Horstman, J. Russ (Cygna) dated 2venber 16, 1985 6.
Gibbs & Hill Drawing 2323-S-0903 7.
Communications Report between B.K. Bhujang et al. (Gibbs
& Hill); R.M. Kissinger (TUGCO); and W. Horstman et al.
(Cygna) dated Septenber 14, 1984 8.
TU Electric, CPSES, " Generic Issues Report - Evaluation and Resolution of Generic Technical Issues for Cable Tray Hangers", Revision 1 9.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analyses for CPSES Nos.1 and 2", Revision 4 i
- 10. Transcripts of the Cable Tray Hanger Design Verification and Meeting between TU Electric Cygna Ebasco, and Impell held a the CPSES Site on January 26 and 27,1987 l
Summary:
Cable tray supports employ angle sections as braces in the following configurations:
in-plane for trapeze type supports, out-of-plane for longitudinal trapeze supports, and in various other orientations for other support types.
The original designs for supports assumed that neutral axes of all menbers at a connection intersected at a common point, thus no connection eccentricities were considered.
TU Electric Comanche Peak Steam Electric Station L
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05/08/87 Revision 13 Page 61 CABLE TRAY SUPPR15 Review Issues List The connection details shown on the design drawings (e.g., Details 4 and 5 on Reference 6) provided a brace working point location which was not consistent with the.
design assump.tions.
Based on a discussion with TUGC0 personnel (Reference 5),
l Cygna learned that the QC inspectors had difficulty in determining the design requirements for the working point locations, and Gibbs & Hill had been requested to provide clarification on the requirements and an allowable tolerance on the working point locations. DCA 20278 and DCA 20418 were issued in response, and the Working Point Deviation Study (References 1 and 2) was performed to consider the fact that the menber neutral axes did not intersect at a conson point and to provide the requested tolerances.
The following are comments on the analyses performed as a part of this study.
A.
Consideration of Design Change Documentations Gibbs & Hill's study (References 1 and 2) does not fully consider the effects of previously approved design change documentation.
The analyses of the generic support types did not consider the effects of all generic design change documents which allow deviations from the original 7
support designs.
(Also - see Review Issue 21. A. )
i Due to the overstress of certain components of several j
support types, a limiting spectral acceleration was calculated, and cut-off elevations were established using the individual floor response spectra. Frames i
below the cut-off elevations were not checked for I
compliance with the study parameters. Frames above the cut-off elevation were analyzed on a case 4y-case basis, but the analyses did not consider the effects of design i
change documents associated with the individual support.
j!
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Vertical'and Transverse Loads on Longitudinal Supports l
The effects of vertical and transverse loads on longitudinal support frames were not considered in the 1
Working Point Deviation Study.
(See Issue Nos. 5 l
and 10.)
l C.
Assumptions Regarding Governing Conponents The portion of the study that evaluated longitudinal trapeze supports only checked menber stress interaction as specified in Section 1.6.1 of Reference 3.
No evaluation was made to ensure that the connections, base angles and anchor bolts are also adequate.
D.
Modelling Assumptions 1.
Instead of modeling a longitudinal support in the tray run, one end of the tray was assumed to be fixed. The effect of this tray boundary condition on the system response was not justified.
Based upon the review of the NASTRAN models used in the Dynamic Analysis Program (Reference 4), Cygna learned that Gibbs & Hill's modelling of these fixed ends did not account for the response spectrum input at those points, but instead fixed them to an absolute rigid ground.
If the same modelling technique was applied in the Working Point Deviation Study, the results of those response spectrum analyses may be incorrect.
2.
The analysis assumed a single 24-inch tray per support level and did not assess the impact of nore realistic multiple tray loadings or other tray widths.
3.
Eccentricities were not properly nodelled.
(See Issue No.10).
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4 The cable trays were nodelled as translationally and rotationally fixed to the support beams. This assumption of tray attachment fixity was not i
justified.
(See Issue No.18.)
5.
The run configurations selected may not be p
representative of actual installations.
Parameters include systems of identical supports, uniform 8'-6" support spacing, and the assumed worst case frame dimensions.
(See Issue Nos.11 and 28.)
[.
6.
The base angle modelling assumed a simply supported beam for two bolt base connections.
In reality, the concrete reactions (pryjng actions) provide flexural restraint to the base angle.
(See Issue No. 26.)
7.
Excitation in the longitudinal tray direction was l
not considered.
8.
The out-of-plane translational degrees of freedom were restrained on trapeze type supports, resulting
!~
in an unrealistically restrained system.
E.
Controlling Element of Supports Gibbs & Hill did not check all support components when determining the controlling support element. For example, support type E4 was assumed to be limited by i
l the load capacity of the Hilti expansion anchors.
Cygna's review indicated that the actual governing component was the Richmond Inserts which were not checked by Gibbs & Hill.
F.
Working Point Location for Two-Bolt Brace Connections on Longitudinal Supports.
l The working point location shown on the design drawing i
does not coincide with the actual line of action of the brace load for two bolt brace connections, e.g., Details MA TU Electric Comanche Peak Steam Electric Station Independent Assessment Program - All Phases 11NNNNNINNINNNNINI l
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CABLE 1 RAY SUPpGt15 Review Issues List "F" and "G" on Gibbs & Hill Drawing 2323-S-0903,' and the brace concrete attachments for support types L-A through L-A, L-8:,, L-B, L-8, L-C;,, L-C2 and Lk on 4
2 4
4 Gibbs & Hill Draw' ng 2323-S-0902. "hese offsets may induce larger tensile loads in the anchorages than originally considered in the designs. These connections were not evaluated as part of the Working Point Deviation Study.
G.
Arbitrary Allowed Working Point Deviations Several support types within Cygna's review scope have specified allowable working point deviations without any supporting calculations.
1.
Detail N (Gibbs & Hill Drawing 2323-El-0601-01-S)
Gibbs & Hill Calculation Binder 2323-SCS-216C, Set 3, Sheet 5 indicates an allowable deviation of 9" i 3" for brace connection to beam. Calculations are not included.
2.
Detail V (Gibbs & Hill Drawing 2323-El-0601-01-S) i Gibbs & Hill Calculation Binder 2323-SCS-216C, Set 3, Sheet 5 states " Low Stress, Brace Working Point Deviation of 6" is acceptable." Calculations to support this statement are not included.
H.
Working Point Deviations by Similarity i
l Several support types within Cygna's review scope have specified allowable working point deviations based on similarity to standard support types.
1.
Detail J (Gibbs & Hill Drawing 2323-El-0601-01-3) is qualified by similarity to Case B.
3 2.
Detail 11 (Gibbs & Hill Drawing 2323-5-0905) is qualified by similarity to Detail 8 (Gibbs & Hill Drawing 2323-S-0903).
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05/08/87 Revision 13 Page 65 CABLE 1 RAY SUPPGt15 Review issues List The calculations for case 83 and Detail 8 (Gibbs & Hill Calculation Binders 2323-SCS-215C, Sets 2 and 4) indicate.that these support types will be overstressed for the allowed working point deviation. Case 4y-case evaluations of Case B3 and Detail 8 supports were performed to determine if all as-designed supports were acceptable.
The support types which had been qualified by similarity were not. included in these case 4y-case reviews; hence, there is no assurance that they are not overstressed also.
I.
Use of Enveloping Cases The Working Point Deviation Study evaluates several support types by grouping them with an enveloping support of similar configuration. Reference 1 Set 2 i
Group 1 includes Cases A, B '.
evaluates two groups.
3 3
4 3 to envelope the other two and C, considering Case C 3
Group 2 includes Cases A, 8, and C, considering case 4
4 4
C4 to envelope the others. For each analysis, the enveloping case is found to be overstressed, and a case 4y-case as-designed review of supports of that type is conducted. The enveloped cases are not all included l
in the case 4y-case reviews, and a separate evaluation is not performed to show design adequacy of the other support types on a generic basis.
J.
Compressive Load Capacity of Menbers As discussed in the status for Issue No. 4. A. Gibbs &
Hill considered the effect of multiple, discrete axial loads on the buckling capacity of the hangers in response to Cygna's concerns. The same effect was considered in the menber evaluations for this study.
1 Gibbs & Hill did not property apply the effect, since the factor is a function of the applied loading, and Gibbs & Hill did not calculate it for each load case.
{
(Reference 7.)
4 a
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Review Issues List Response:-
In accordance with Reference 8, Appendix A12 the cable tray support design verification effort will not rely upon the results of Gibbs & Hill's Working Point Deviation Study.
Cable tray supports will be evaluated on an individual basis using as4uilt support configurations.
j Reference 9 Attachment I provides details for the consideration of the brace working point deviation in the support finite element models. Both Ebasco and Impell use these guidelines. For braces attached directly to the back of a vertical channel a set of conditions are provided such 2
that if these conditions are satisfied, the working point deviation need not have to be modelled.
During a discussion between Cygna and Ebasco (Reference 10), Ebasco indicated that the specified conditions are based on the requirement that if the brace neutral axis passes through the panel zone i
(defined by the intersection of the post and tier), the brace working point location will have no effect on the 4
behavior of the support.
Status:
Closed with respect to Gibb's & Hill's Working Point Deviation Study. This issue is not applicable to the j
current design verification effort.
Open: Additional review by Cygna of the basis for Attachment I, Reference 9 is required.
i l
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- 13. Reduced Spectral Accelerations
References:
1.
Gibbs & Hill Calculations, " Analysis of Alternate Detail 1" 2.
Gibbs & Hill Calculation Binder SCS-101C, Set 3, Sheet 247. Revision 9 3.
Gibbs & Hill Calculation Binder SCS-215C, Set 4 4.
Gibbs & Hill Calculation Binder SCS-101C, Set 2 Sheets 131 & 132, Revision 5 i
5.
Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cable Tray Hangers for CPSES Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES Unit 2", Revision 6 6.
Ebasco Instruction, " General Instruction for Cable Tray Hanger Analysis for CPSES, Nos. I and 2", Revision 4 7.
Impe11 Instruction PI-02, " Dynamic Analysis of Cable Tray Systems" Revision 5 1
(
Susamry:
For the qualification of the supports discussed below, Gibbs
& Hill used reduced spectral accelerations based on a calculated support-tray system frequency. These analyses assumed that all supports on a tray run are of the same type and have equal spacings.
(See Issue No.11.) These studies are not representative of the cable tray installations at CPSES.
I A.
Transverse Supports l
A reduced acceleration was used for the analysis of j
transverse supports, such as type A, which was used in 4
analysis of Alternate Detail 1.
(Reference 1.) This acceleration corresponds to a calculated frequency which TU Electric Comanche Peak Steam Electric Station k A Independent Assessment Program - All Phases
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05/08/87 Revision 13 Page 68 CABLE 1 RAY SUPMRTS Review Issues List is higher than tisc.t corresponding to the spectral peak. This frequency was calculeted using a system model of identical supports equally spaced at 8'-6" and a tray weight of 35 psf. The results of this stu@ may not be valid for all installations as discussed in Issue No. 11.
B.
Longitudinal Supports For longitudinal supports (e.g., type SP-7 with brace (Reference 3), L-Al (Reference 2), etc.), the frequency calculations did not include the effect of the axial frequency of the tray and the eccentricities between the tray and support.
C.
Effects of Base Angle Flexibility The flexural flexibility of the base angle supporting the brace of the longitudinal supports was not considered in frequency calculation.
(References 3,4.) Flexural deformation of the base angle can result in significant reduction in support frequency.
l
Response
The current cable tray support design verification effort does not rely on the results of the Gibbs & Hill analyses discussed in this issue. Cable tray supports are design verified based on the as built tray and support configurations.
A.
In accordance with Reference 5. Sections III.1, III.2 and IV.2.c. Ebasco calculates cable tray system frequencies based on the as built support configurations l
and tray spans. The seismic input accelerations are based on these f.'aquencies.
In accordance with Reference 7, Impell analyzes the cable tray supports using response spectrum analyses of system models based on as built geometry.
The techniques used by Gibbs &
i Hill are not employed.
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For equivalent static analyses of longitudinal supports, Ebasco considers the axial stiffness of the tray (Reference 5,Section IV.2.c) and the effect of the eccentricities between the support and the tray. For Ebasco's and Igell's response spectrum systems analyses, tray stiffness and support eccentricities are considered.
C.
Ebasco and Impell have performed studies to determine the appropriate stiffness for base angle connections.
These stiffness valves are included in Ebasco's support models (Reference 6. Attachment G9) and Impe11's system 4
models (Reference 7 Sections 3.2.5).
Status:
A.
Closed.
B.
See Issue No. 24 for concerns regarding the modelling of the eccentricities between the tray and the support.
C.
See Issue Ib. 3.I for a discussion of the base angle stiffness studies.
i i
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- 14. Non-Conformance with AISC Specifications
References:
1.
AISC, " Specifications for the Design. Ferication and l
Erection of Structural Steel for Buildings", 7th edition 2.
CPSES, FSAR, Sections 3.8.3.2 and 3.8.4.2 3.
Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 2", Revision 6 4.
Transcripts of Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna. Ebasco and Impell held at the CPSES site on January 26 and 27,1987 5.
Impe11 Instruction PI-03, " Qualifications of Cele Tray i
Supports", Revision 4
}
~
6.
Comunications Report between S. Harrison, J. Muffett (TV); P. Harrison (Ebasco); R. Wheaton, 8. Ramsey (Impell); and N. Williams, S. Tuminelli, D. Leong, J.
Russ. W. Horstman (Cyg1a), dated March 6, 1997, 11:30 a.m.
7.
Ebasco Instruction, " General Instructions for Cable Tray
[
Hanger Analysis for CPSES Nos.1 and 2", Revision 4 i
8.
Impe11 Report, "CPSES Cele Tray System Analysis / Test l
Correlations" Report No. 09-0210-0017 Revision A l
(Preliminary Issue) i i
9.
ANCO Testing Laboratories, " Test Plan - Dynamic Testing of Typical Cable Tray Support Configurations', Document e
No. A-000150, Revision 1 10.
Impe11 Special Study 2. 5.9, " Oversize Bolt Holes",
(
Preliminary Issue l
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Reference 2 commits to designing the cable tray supports in accordance with Reference 1.
Gibbs & Hill has not properly considered the requirements. of Reference 1, as discussed b elow.
A.
Urbraced Length for Axial Buckling Section 1.8.4 (Reference 1) requires that the slenderness ratio, k1/r,be less than 200 for compression members. Depending on the approach selected for the resolution of Issue b. 4, this requirement may not be met. For example, if the friction type clamp cannot provide adequate restraint in the longitudinal direction, the k value should be taken as,2.0 for trapeze type and cantilever type supports.
Consequently, k1/r = 257 for a 5'-9" C6 x 8.2 hanger or b eam.
B.
Urbraced Length for Lateral Torsional Buckling Section 1.5.1.4.6a (Reference 1) requires that Equation 1.5-7 be used to calculate the allowable bending stress for channels.
In the denominator, "1" is the urbraced length of the compression flange. Cygna found the following instances where the AISC Specifications were not considered or were inproperly applied:
1.
Gibbs & Hill's Working Point Deviation Study (Issue Ib.12) uses 22 ksi for the allowable flexural stress without checking Equation 1.5-7.
Since the frame heights are on the order of 144", an allowable flexural stress of 15 ksi is calculated by Equation 1.5-7.
2.
Detail SP-7 and similar supports consider "1" to be the distance from the base attachment to the tray centerline and not to the outside tray rail where TU Electric Comanche Peak Steam Electric Station b
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the load is applied. Use of the larger distance-X wi11 result in lower allowable bending stresses.
S C.
Bolt Holes in Menber Flanges Reductions in the section properties of beams due to bolt holes in their flanges per Section 1.10.1 (Reference 1), were.not considered.
(See Issue No 9.)
.D.
Lacing of Dosle Angles Dosle angle braces are designed as composite menbers, without providing lacing per Section 1.18.2.4.
(Reference 1.)
(See Issue No. 7.)
E.
Eccentric Connections Section 1.15.2 (Reference 1) discusses eccentric connections. This section requires that any axial menbers not meeting at a single working point be designed for the eccentricities. For example, this section of the specification applies to supports with single angle braces (SP-7 with brace, L-A, etc). The l
1 gusset plates connected to these braces must also be designed for the eccentricities.
[
F.
Oversize Bolt Holes Section 1.23.4 (Reference 1) specifies bolt holes to be 1/16" larger than the nominal bolt diameter. The bolt holes for anchor bolts in base plates / angles (per Gibbs
& Hill Drawing 2323-5-0903) and for tray clamps (per DCA 17838 Revision 8) are specified as 1/8" larger than the nominal bolt diameter. Therefore, the bolt holes in l
Gibbs & Hill's designs should be considered oversized l
and should be treated as such in bearing connection i.
calculations.
G.
Use of the Allowable Congressive Stress For Secondary Menb ers TV Electric Comanche Peak Steam Electric Station L
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-.%.._,-.m___mm..
~... - - -
m- -, - - -- --
05/08/87 Revision 13 Page 73 CABLE 1 RAY SUPP(RTS Review Issues List For the design of the longitudinal brace for support type SP-7 with brace, the brace was assumed to be a secondary menber, and allowable cogressive stresses were calculated per section 1.5.1.3.3 (Reference 1).
Since thi's is the sole meter providing longitudinal load carrying capability, it should be considered a primary menber, and sections 1.5.1.3.1 and 1.5.1.3.2 are applicable.
Response
A.
See Issue No. 4. A B.
Ebasco, Reference 3, requires adherence to the AISC Specifications but does not specifically address the use of Eqn.1.5-7 or the calculation of the unsupported length.
In Reference 4 Ebasco indicated that the total' length of the tier menbers (horizontal channels) and the length of the post (vertical channels) between tiers is to be used as the unsupported length.
Impell, Reference 5. Section 4.1.4, specifies that the full length of the tiers and the full lengths of the posts shall be used as their unsupported lengths. The trays are not assumed to provide bracing to the compression flanges of the channels.
However, in Reference 6. Igell indicated that, in some cases, they do take credit for bracing from the trays.
C.
See Issue No. 9.
D.
See Issue No. 7. A.
E.
See Issue Nos. 7. A and 7.B for a discussion of the eccentricities associated with single and dotble angle breces. The effect of eccentric loading on the gusset plates used at the ends of angle braces is considered.
In Reference 7 Section I.a. Ebasco specifies that gusset plates be evaluated for an eccentricity equal to 1/2 of the gusset plate thickness plus 1/2 of the leg r
"~
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thickness of the attached angle.
Impe11 evaluates gusset plates in accordance with Attachment 7 of i
Refdrence 5.
The method of considering eccentric loading 1.s not specified in Reference 7.
I F.
In Reference 10 Impell addresses the oversized bolt holes used for the anchor bolts and the tray clasps.
This report indicates that the use of 1/8" oversized holes is standard practice for ane, hor bolts and, therefore, their use is not an issue. For the clamp l
boits - it is indicated that the additional relative displacement of the tray and support is not significant.
In fact, Impell asserts that the slipping will introduce l
additional desping.
It is also indicated that, although the loading is not uniformally distributed among the bolts in a connection at working load levels, the ultimate capacity of the connection is not reduced.
The cable tray supports used in the ANCO dynamic testing l
program (Reference 9) will include installations with
(
oversized bolt holes. The igact of the oversized holes l
will be investigated in the correlations of the test l
results to those for finite element models.
(Reference 8.) However, Cygna's review of the ANCO test plan indicates that 1/16" oversized bolt holes are used in the test configuration.
Ebasco has prepared a calculation involving a statistical analysis of a sample of bolt hole sizes and edge distances. The calculation was to determine the l
maximum bolt hole size present in the cable tray support l
cogonents. Ebasco also prepared a position paper.
"Effect of Bolt Hole Oversize on CTH Adequacy", which sumarized the results of the statistical analysis and offered qualitative justification for the adequacy of support installation with oversize bolt holes.
G.
All members, including bracing menbers will be evaluated using the allowable cogression stresses for primary l
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Status:
A.
See Issue No. 4. A.
B.
Open: Additional review by Cygna required.
C.
See Issue No. 9.
D.
See Issue No. 7. A.
E.
See Issue Nos. 7. A and 7.B for status of eccentric loading on angle braces. Additional review of gusset l
plate evaluation criteria is necessary.
F.
Open: Additional review of the ANCO test procedures, the system test correlations study, and both Impell's and Ebasco's evaluations of the effects of oversize bolt holes is required.
G.
Closed.
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- 15. Menber Sestitution
References:
1.
Communications Reports between R.M. Kissinger (TUGCO) and J. Ru.ss (Cygna), dated January 17,1985, 8:15 a.m.
and 3:45 p.m.
- 2.
CMC 69335, Revision 1, dated 9/21/82 3.
Gibbs & Hill Drawing 2323-S-0901, Revision 4 4.
Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cable Tray Hangers for CPSES Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 2", Revision 6 5.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for CPSES Nos. I and 2", Revision 4 6.
Impe11 Instruction PI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 7.
Transcripts of Cable Tray Hanger Design Verification Meeting between TU Electric Cygna. Ebasco and Impell held at the CPSES site on January 26 and 27,1987 8.
Impe11 Instructions PI-11. " Cable Tray System Analysis and Qualification Closeout", Revision 2.
l Summary:
Note 9 on Gibbs & Hill Drawing 2323-S-0901, Revision 4 states:
Structural menbers shown on drawing nunbers 2323-S-900 series may be ssstituted by one step heavier 4hape of the same size.
This note allows craft to ssstitute a menber from one series with a menber from another series, e.g., an American Standard Channel (C) for a Miscellaneous Channel (MC) or TU Electric Comanche Peak Steam Electric Station i
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05/08/87 Revision 13 Page 77 CABLE 1 RAY SUPP(RTS Review Issues List vice versa, as long as the ssstituted shape is heavier than, but of the same depth as the original meter.
Cygna is concerned that this note allows the use of ssstitute sections which are heavier, but have lower section moduli.
At a later date, Reference 2 was issued, providing the following clarification:
Structural menbers shown on drawing nusers 2323-S-900 series may be ssstituted by a menber of the same size and next heavier shape determined by the material on site. The next step heavier shape will be governed by sections as shown in AISC Manual of Steel Construction.
Examples are shown on sheet 2 of 2.
The examples shewn on sheet 2 of Reference 2 include the ssstitution of a C4 x 7.25 for a C4 x 5.4, a C6 x 10.5 for a C6 x 8.2, etc. This clearly indicates that the ssstitution should be of the same series as the specified menb er.
Cygna's concern is what types of ssstitutions were performed by the craft and accepted by the QC inspectors during the time between the issuance of Reference 3 and Reference 2.
Cygna was unable to locate any requirements for documenting menber ssstitutions.
Within Cygna's walkdown scope, such a ssstitution was l
identified for support nunber 6654.
(See Issue No. 20. )
The design required an MC6 x 12, and the installed menber -
was a Cg x 13, which has a smaller section modulus (Sx" 3 for an f
5.80 in for a C6 x 13 compared to S = 6.24 in MC6x12). For the other supports listed in Issue No. 20, the required MC6x12's were ss stituted with C6 x 8.2's, a ssstitution not permitted by Reference 2.
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Response
- The design verifications for cable tray supports 'will use
-the asJbuilt support drawings. The analyses and stress evaluations will be based on the installed med)er sizes.
This is required for Impe11 in Reference 6. Section 3.2 and for B>asco-in Reference 4. Section 'III.2.
In cases where the installed med)er size cannot be determined (inaccesstale attributes) the as-designed med)er size will be used,' considering to potential sd)stitution of an American Standard channel ("C") of one step heavier for a miscellaneous channel ("MC") if the sd>stitution will result in a reduction in med>er capacity. For 8)asco, this is specified in Reference 5 Attachment X Section IV.
Impell cites this procedure in Reference 8.
Status:
Open:
In accordance with Reference 7 the resolutien of this issue is dependent upon the development of a unified approach for the consideration of inaccessible attributes.
1 l
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- 16. Weld Design and Specifications
References:
1.
KH. Williams (Cygna) letter to V. Noonan (US NtC),
" Response to RC Questions," 83090.023,' dated March 8, 1985 l
2.
Communications Report between S. Chang, P. Huang (Gibbs
& Hill) and W. Horstman, J. Russ, N. Williams (Cygna) dated October 27, 1984 3.
Communications Report between S. Chang, P. Huang (Gibbs
& Hill) and W. Horstman, J. Russ, N. Williams -(Cygna) dated Novenber 13, 1984 4
Connunications-Report between S. Chang, P. Huang-(Gibbs
& Hill) and J. Russ (Cygna) dated Novenber 17, 1984 5.
Connunications Report between R. M. Kissinger (TUGCO) and J. Russ (Cygna), dated Novenber 30, 1984 6.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tray Support Review Questions," 84056.041, dated Feruary 12, 1985 7.
Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 1", Revision' 3, and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES, Unit 2", Revision 6 t
8.
Ebasco Instruction, " General Instruction for Cable Tray Hanger Analysis for CPSES Nos. I and 2", Revision 4 9.
Impell Instruction PI-03, " Qualification of Cable Tray Support {, Revision 4
- 10. Transcripts of Ctle Tray Hanger Design Verification Meeting between TU Electric, Cygna. Ebasco and Inpell held at the CPSES Site on January 26 and 27,1987 TU Electric Comanche Peak Steam Electric Station I
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- 11. Ebasco Cable Tray Hanger Calculations:
CTH-1-102,' Revision 0 CTH-1-121, Revision 0 CTH-1-125 Revision 0
- 12. Connunications Report between G.' Ashley, et._ al.
(Impell); J. Russ, et. al. (Cygna); R. Alexandru, et.
al. (Ebasco); and S. Harrison, et. al. (TV Electric) dated February 13, 1987, 11:30 a.m.
- 13. AISC " Specifications for the Design, Fabrications and Eviction of Structural Steel for Buildings", 7th Edition 14 AWS D1.1-79, " Structural Welding Code - Steel",1979
- 15. Communications Report between R. K1elbach, P. Harrison-(Ebasco); and J. Russ (Cygna), dated March 16, 1987, 1:30 p.m.
- 16. Ebasco Report:
" COMBS Computer Program - Calculation of Stresses in Composite Channels, Descriptions and Verification of Computer Program", Revision 2.
I
- 17. Communications Report between R. Wheaton, et al (Igell); J. Muffett, et al (TU Electric); and N.
Williams, et al (Cygna), dated March 6,1987.
Summary:
Cygna has noted the following discrepancies in the weld designs for cable tray supports.
l A.
Weld Details Not Shown on Design Drawings The design drawings are missing the weld details for several support types as described in Reference 1, Attachment C.
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Weld Size Discrepency between Design and Assed)1y Drawings Per discussions with Gibbs & H111/TUGC0 (References 2, 3, 4 and 5), Cygna has noted that the weld sizes shown on the assed)1y drawings differ from those shown on the design drawings and those that were assumed in the Gibbs 8 Hill calculations.
C.
Eccentricities in Welded Connections Eccentricities were not considered in the design of welded connections. Some examples include:
1.
Detail SP-7 with brace and similar connections require a partial penetration groove weld at the gusset plateA>eam connection. The design calculations did not consider the eccentric load transfer from the brace med)er. The eccentricity of the brace loads results in a weld stress in excess of the allowd)1e.
2.
Weld designs for the lap joints between channels and between the base angle and attached channel did not consider the eccentricity between the applied loads from the connecting med)ers and the plane of the weld.
D.
Base Metal Thickness The weld designs did not consider the thickness of the connected parts. This issue was identified by DCA 2365, Revision 2, but was never considered in the design calculations. Gibbs & Hill's weld designs. assumed that the full weld throat would be developed without considering the thickness of the connected met er. For example, the weld size for support desians employing C6 x 8.2 channels with a fillet weld crossing the wd) of the channel is limited to the 0.2 inch wd> thickness.
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.l 05/08/87 Revision 13 Pa ge 82 CABLE TRAY SUPPORTS Review Issues List-4 Gribbs & Hill designs specified a 5/16" fillet weld size
.and did not reduce the throat to account for the minimum unterial thickness. Cases where this ney be a problem.
include: Details E, F, G, H, J and K on Gibbs & Hill Drawing 2323-El-0601-01-S; SP-7 using an L6x4x3/4 base angle; and the Detail 2/2A on Gibbs & Hill Drawing 2323-S-0903 as modified per CMC 58338.
E.
Minimum Weld Lengths Gibbs & Hill assumed an incorrect minimum weld length i
for the beam / hanger base angle connection. Gibbs & Hill i
assumed a weld length of 1-k, where 1 = angle leg width and k = distance from back of angle leg to end of fillet.
However, because of the existence of the curve at the angle toe with radius, r (approximately equal to one-half the leg thickness), the actual weld length is 1-k-r.
g F.
Minimum Weld Size Requirements TW)1e l.17.5 of the AISC Specifications (Reference 13) specifies the minimum weld sizes to be used in con-
.nection designs. These weld sizes are based on the thickness of the thicker part joined. The weld size need not exceed the thickness of the thinner part joined except as required by a stress calculation. This td)1e is based on AWS 01.1 (Reference 14) which is incorporated in the AISC Specifications by reference.
l AWS D1.1 requires the use of preheating the thicker part if the minimum weld size is not used. For material up to 3/4" in thickness, a preheat temperature of 70'F is required. For material greater than 3/4", but less than 1-1/2" thick, a preheat temperature of 150*F is required.
Within Cygna's review scope, a minimum of eight supports do not meet the minimum weld size requirements of AISC.
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CABLE TRAY SUPP(RTS Review Issues List G.
Intermittent Fillet Welds Several cable tray support designs employ composite sections (e.g. SP-7 with brace, Detail 11 on. drawing 2323-S-0905, etc.) which are joined using intermittent fillet welds. An evaluation of these welds was not provided by Gibbs & Hill in their, design calculations, An evaluation of such welds should consider both the L
shear flow due to flexure of the composite section and the shear associated with St. Venant and warping torsion.
H.
Base Angles Welded to Enbedded Plates Cable tray supports can be attached to enbedded plates by providing a fillet weld along the toe and heel of the base angle as a stbstitute for the required anchor bolts (DCA 3423, Revision 1). The CVC for this DCA indicates that calculations were not required in the design verification of this DCA.
Response
A.
The design verification is based on the as built weld sizes and configurations per Reference 7.Section III.2 for Ebasco and Reference 9, Sections 3.0 and 4.3 for Inge11. The approach to be used for inaccessible welds is currently not finalized.
B.
See response for Issue No. _16. A.
C.
The project design criteria (References 8 and 9) do not l
address the consideration of eccentric loadings on the welds.
Based on a review of several Ebasco calculations, (Reference 11), Cygna determined that Ebasco evaluates welds by obtaining end forces for the menber attached to and weld and adding in the additional bending soments due to the eccentricity between the menber center of gravity and the plane of the weld pattern.
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-05/08/87-Revision 13 Page 84 CABLE RAY SUPPGtTS Review Issues List In Reference 12 Impell indicated that the welds are evaluated using the menber end forces for the menber attached to the weld without considering the additional bending moments. Therefore, the eccentricities are not considered.
D.
Shear stresses in the base material will be considered in the weld design verifications. Reference 8,Section IX, states that Ebasco will consider both the weld size and the base metal thickness in evaluating weld capacities. Reference 9. Section 4.3 states that Impell will check the base metal shear stresses when an allowable stress greater than 21 ksi is used for fillet welds. This does not clearly indicate how base metal shear stresses will be considered or what will be done when the base metal is thinner than the weld throat.
In Reference 10, Impell indicates that Reference 9 will be revised to clarify the weld evaluation. process.
E.
See response for Issue Ib.16. A.
i F.
In Reference 15, Ebasco stated that a review of the Brown & Root welding procedures indicated that low-hydrogen electrodes had been used for the cable tray supports. These electrodes require a minimum preheat temperature of 50'F.
A review of purchase orders showed that only these electrodes were used at the CPSES site.
G.
Both consultants will evalu'te the adequacy of intermittent fillet welds 4he basis of the as4uilt weld patterns.
In Reference 9, Section 4.3 and Attachment 8 Impell requires that intermitent fillet welds be evaluated.
This evaluation is %ased on the capacity necessary to resist slip or novement between the two channel sections." The stresses in the weld due to torsion are not considered.
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05/08/87-Revision 13 Pa ge 85' CA81.E 1 RAY SUPPGtTS Review Issues List Ebasco evaluates the composite sections using an in-house coguter program " COMBS",' (Reference 16). This program includes an evaluation of the stresses in the-intermittent fillet welds which considers the shear due to flexure and the shear and normal stresses due to torsional loading.
H.
This type of connection does not occur frequently at CPSES. They are evaluated on a case 4y-case basis.
During Cygna's audit of Ebasco's cable tray hanger design verification effort, several supports which had the base angle welded.to an enbedded plate were identified. The analysis of the base angles and welds for these supports were performed via finite element models representing the base angle, welds and sestrate.
During the audit of _Igell, Cygna noted that such connections were evaluated via hand calculations. As discussed in Reference 17, the load distribution assumed in the3e calculations is based on a rigid plate assumption and does not account for the stiffening effect of the outstanding leg of the base angle or the location of the applied load with respect to the centroid of the weld pattern.
Status:
A.
Open:
In Reference 10, TU Electric indicated that the Project is currently in the process of developing a i
unified approach to the-evaluation of hidden / inaccessible support attributes.
Cygna will review this approach when available.
B.
See Status for Issue No. 16.A.
C.
Open:
Igell should provide the justification for not l
including the eccentricity effects in weld evaluations.
1 D.
Open: Cygna will review the revised criteria in Reference 9 when available.
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See status for Issue No. 16.A.
F.
Open:
Internal discussion of the welding procedures is required by Cygna.
G.
Open: As discussed in Reference 17, Cygna will review Impe11 Calculation M-49.
H.
Open:
Per Reference 17, Impell will provide an evaluation of the method used to determine load distribution in the weld to the enbedded plate.
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- 17. Esbedded Plates Design
References:
- 1.. M.H. Williams (Cygna). letter to J.B. George (TUGCO),
" Cable Tray Support Review Questions," 84056.041, dated February 12, 1985 Attachment A, question 1 2.
L.M. Popplewell (TUGCO) letter to N.H. Williams (Cygna)
I dated April 19,1984, page 11 3.
Comunications Report between N. Williams, J. Russ, W.
Horstman (Cygna); R. Kissinger, T. Keiss (TUGCO); and B.
Bhujang, P. Huang, S. Chang (Gibbs & Hill) dated Septenb er 15, 1984
\\
4.
Communications Report between M. Warner (TUGCO) and N.
Williams, J. Minichiello, J. Russ (Cygna) dated F&ruary 27, 1985 t
5.
Gibbs & Hill Calculation Binder 2323-SCS-146C, Set 4, Sheet 3-9, 21 6.
Gibbs & Hill Drawing 2323-5-0919, Revision 3 7.
Brown & Root Installation Procedure CCP-45, " Permanent and Temporary Attachments to Weld Plates," Revision 1, 8/18/80 8.
Gibbs & Hill Specification 2323-55-30, Appendix 4
" Design Criteria For Esbedded Plate Strips," Revision 1 9.
N.H. Williams (Cygna) letter to W.G. Counsil (TUGCO),
" Cable Tray / Conduit Support Review Questions,"
84056.089, dated October 21, 1985
- 10. Transcripts of the Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna Ebasco and Impell at the CPSES Site on January 26 and 27,1987' TU Electric Comanche Peak Steam Electric Station L IL A Independent Assessment Program - All Phases 111111111111111111111111111lllJob No. 84056 PRJ:RIL
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b 05/08/87 Revision 13-Pa ge 88 CABLE 1 RAY SUPPGtTS Review Issues List Summary:
A.
Prying Action on Nelson Studs GM>bs 8 Hill performed capacity calculations for cd>1e tray support attachments to eWbedded strip plates.
Cygna's review of these calculations indicates that the-calculated capacities may not have considered the effect of prying action on the tension in the Nelson Studs.
B.
Stiffening Requirements for Moment Attachments Questions from Cygna's pipe support reviewers and cable tray reviewers on the stiffening requirements for ed>edded plate moment connections elicited conflicting responses from TUGC0 personnel. The pipe support response indicated that attachments to ed>edded plates act as stiffeners for mosent connections (Reference 2),
while the cd>le tray support response indicated that any moment attachment must be stiffened or sufficiently analyzed. (Reference 3.)
C.
Capacity Reduction for Attachsent Locations Cygna has noted that calculations for cd>1e tray supports attached to enbedded plates did not consider the capacity reductions for attachment locations given in Gibbs & Hill Specification 2323-SS-30 " Structural Ed)edments".
(Reference 1.) Cygna has requested any documents which address the corrective action associated with the issuance of Specification 2323-SS-30.
(Reference 9.)
D.
Inspection Requirements for Attachment Spacing A review of Brown & Root Procedure CCP-45 (Reference 7) indicates that any two adjacent attachments to an ed>edded strip plate must be separated by a minimum of 12".
Based on a discussion between Cygna and TUGC0 (Reference 4), it was determined that, even though the installation procedure requires this separation, the TU Electric Comanche Peak Steam Electric Station L*I(
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05/08/87 Revision 13 Page 89 CABLE 1 RAY SUPPGt15 Review Issues List inspection procedures for cable tray supports do not require an inspection of this attribute.
Cygna walkdowns noted several instances where the separation between attachments to enbedded plates were less than 12".
(See Pipe Support Issue No. 9.) Cygna is concerned that the lack of control of attachment spacing nay have an impact on the design adequacy of the attachments.
E.
Installation of Details E, F, G, and H on Enbedded Plates Reference 5 is the design calculation for the installation of-Support Details E,F G, and H (Gibbs &
Hill Drawing 2323-El-0601-01-S) on enbedded strip plates. ' A maximum tributary tray span of 7'-6" is used in these calculations.
Note 9 on Reference 6 states:
The supports will have a location tolerance of i 12" in the direction parallel _to the-tray and i 2" perpendicular to the tray.
- However, spacing between any two adjacent supports shall not exceed 9'-0" for Unit I and Common Areas...unless otherwise noted on the drawing.
Supports installed in accordance with this drawing note-may have to resist loads due to a 9'-0" tributary span,.
I'-6" greater than the design tributary span.
F.
Spacing Requirements Between Enbedded Plates and Concrete Anchors Gibbs & Hill Specification 2323-SS-30 (Reference 8) provides spacing requirements between enbedded plates and Hilti expansion anchors. During Cygna's cable tray support walkdowns, an instance was noted where an enbedded plate was located near an opening in a concrete wall. Several Hilti expansion anchors were installed l
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.Cygna was unable to determine how the minimum spacing requirements would be applied to situations where the expansion anchor is installed in a surface perpendicular
.to the enbedded plate.
Response
Per the discussion in Reference 10, the design verification of the enbedded plates for CPSES will be addressed by Stone and Webster Engineering Corporation (SWEC) as a part of the Civil / Structural Action Plan. The calculations associated with enbedded plate capacities and the procedures used in enbedded plate walkdowns and evaluations will be made available to Cygna for audit upon completion.
Status:
Open pending review of SWEC's evaluation of enbedded plates.
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- 18. Cable Tray Clamps-
References:
1.
Gibbs & Hill Drawing 2323-S-0902, Revision 5 2.
TUGC0 Drawing TNE-51-0902-02, Revision CP-2 3.
Communication Report between T. Keiss (TUGCO) and W.
Horstman (Cygna) dated November 15, 1984 4.
Ebasco Instruction " General Instructions for Cable Tray Hanger Analysis for Comanche Peak SES Nos. I and 2",
Revision 4 5.
Ebasco Procedure SAG.CP11 " System Analysis for Cable Tray and Hanger Assenbly for CPSES Units 1 and 2",
Revision 2 6.
Impe11 Calculation M-10. " Clip Angle Stiffness",
Revision 2 7.
Impe11 Calculation M-19, " Clip Stiffness Production Values", Revision 2 l-8.
Impe11 Report 09-0210-0017 "CPSES Cable Tray System Analysis / Test Correlation", Revision A 9.
Impe11 Instruction vI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 10.
Impe11 Calculation M-28, " Tray Clamp Behavior".
Revision 0 11.
Igell Instruction PI-11. " Cable Tray, System Analysis and Qualification Closeout" Revision 1 Summary:
Two general cc.tegories.pf cable tray clamps are used at CPSES.
" Friction" type clamps are installed on transverse type supports (e.g., A, 8, SP-7, etc. ).
These clags are 1
assumed to provide vertica' and horizontal transverse load TU Electric Comanche Peak Steam Electric Station Li[ J k A
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" Heavy duty" clamps are installed on longitudinal trapeze supports. (e.g., L-A, L-B, etc. ), three-way g
g supports- (e.g., SP-7 with brace, Detail 8 on drawing 2323-5-0903, etc.), and transverse supports, where interferences (e.g., tray splice plates, fittings, etc.)
prevent.the installation of friction type clamps.
Heavy duty clamps are designed to transfer vertical, horizontal transverse, and longitudinal tray loads to the cable tray support beam. References 1 and 2; DCA 3464, Revision 23; DCA 6299, Revision -7; and DCA 20331, Revision 0 provide clag configuration details.
In addition to the indicated load transfers between trays and supports, Gibbs & Hill has assumed other load transfer mechanisms in order to justify behavioral assumptions made in the support designs.
A.
Friction Type Clamps For " friction" type clamps,. the following assumptions have been made in order to justify the system concept.
(See Issue No.10.)
o The trays will provide out-of-plane bracing to trapeze supports to reduce the buckling length of the vertical hanger menbers.
(See Issue No. 4. )
o The trays will provide lateral bracing to the cogression flanges of the horizontal beams.
(See Issue No. 24.)
o The trays will provide out-of-plane bracing to supports to prevent frame translation which would result in increased anchor bolt tensile loads.
(See Issue No. 3. ) s o
The cable trays will transfer out-of-plane inertial loads from transverse supports to longitudinal supports on the same tray run.
(See Issue No. 6. )
TU Electric Comanche Peak Steam Electric Station h.
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The development of minor axis bending moment in the beams due to the horizontal eccentricity between the beam neutral axis and the clamp bolt is minimized by.
a bending moment in the cable tray.
(See Issue No.
24.)
o For vertical loading, the development of torsion in the beam due to the eccentricity between the clamp location and the beam shear center is prevented by flexure of the cable tray. This assumes a full moment fixity between the tray and the support b eam.
(See Issue No. 24.)
B.
Heavy Duty Type Clamps For heavy duty clamps, all of the above assumptions are also applicable. Additionally, the following assugtion was made by Gibbs & Hill.
o The development of torsion due to longitudinal loads on three-way supports using composite beam sections (e.g., SP-7 with brace and Detail 8 on Drawing 2323-S-0903, etc.) is prevented by flexure of the cable tray. This assumes a full moment fixity between the tray and the support beam.
(See Issue No. 24. )
The assumptions described above are valid only if the clamps can provide suitable displacement and rotational compatibility between the tray and the support beam.
Based on a discussion with TUGC0 (Reference 3), Cygna determined that installation tolerances (Reference 2; DCA 6299, Revision 7; DCA 20331 Revision 0; and CMC 93450, Revision 4) have been adopted which allow gaps between the tray side rails, the support beam, and the tray clags.
In order to provide the assumed cogatibility, " friction" type clamps must be cinched sufficiently to develop friction at the tray / beam and TU Electric Comanche Peak Steam Electric Station l
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05/08/87 Revision 13 Page 94 CABLE 1RU SUPP(RTS Review Issues List tray / clamp interfaces. The existence of gaps will preclude the development of the normal contact force required for frictional resistance.
Response
A.
The effects of the connectivity provided by friction type clamps between cable trays and transverse supports is considered in the design verification in two ways.
These assumptions on connectivity affect the issues regarding out-of-plane inertial loads, base angle rotation, effective length for compression menbers, etc.
In all analyses performed by Impell, the clamps are assumed to provide full connectivity between the cable j
L trays and the supports.
In References-6 ana 7 Impell has developed clamp stiffness values associated with the six translational and rotational degrees of freedom of the tray to support connections. These stiffnesses are sununarized in Section 3.2.4 of Reference 9..
The transmission of forces and moments between the cable tray and the cable tray support, in spite of the poten-tially significant gaps between the clamps and the tray, is justified based on the interpretation of the results of a series of dynamic tests of full scale nodels of cable tray systems. The test results are sununarized in i
Reference 8.
Analytical justification is provided in Reference 10.
In a large portion of the analyses performed by Ebasco, the friction type clamps are assumed to be incapable of transmitting loads in the tray axial direction. The l
(
finite element nodels used, both for the individual I
supports analyzed by the equivalent static method (ESM) and the system models analyzed via the response spectrum method (RSM) assume no axial connectivity between the tray and the supports. References 4 and '5 provide Ibasco's modelling guidelines.
1.
j TU Electric 4
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05/08/87-Revision 13 Page 95 CABLE 1 RAY SUPPGtTS Review Issues List In light of the connectivity assumption used by Impell, B>asco will evaluate the impact of the differences between the assumptions used by the two consultants.
In accordance with Attachment Z of Reference 4, B)asco will reevaluate cd>1e tray supports analyzed by the ESM to _
determine the impact of tray / support connectivity on the supports previously qualified assuming no connectivity.
Similarly, for supports analyzed by RSM, Reference 5 specifies that a nusber of systess will be reanalyzed assuming tray / support connectivity to evaluate the impact of this assumption.
Therefore, the current cd)le tray support design verification effort assumes connectivity between the tray and the support and thus, includes the same load transfer mechanisms employed by Gibbs & Hill.
B.
For supports analyzed by the static or equivalent static-methods, B)asco assumes that the heavy duty clamps provide three directional force transfer without any moment transfer.
(Reference 4. Attachment B2.) Thus, the heavy duty clamps do not reduce the torsion or bending moments due to the eccentricities between the cd)le tray and the support.
For cd)le tray supports included in response spectrum analyses (B)asco's RSM models and Impell's system models), heavy duty clamps are assumed to provide force and moment. transfer between the tray and the support.
The clamps are modelled as linear elastic spring elements having stiffness properties calculated in References 6 and 7.
These values are documented in Reference 5 and Reference 9.
Based on the results of the cd>1e tray system testing program, Impell has determined that higher clasp stiffness values than those documented in Reference 5 and 9 can be used.
(References 8 and 11.)
4 1
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05/08/87 Revision 13 Page 96 CABLE TRAY SUPPGtTS Review Issues List Justification for the differences in assugtions Ebasco has made for the static method and the response. spectrum method has not been provided.
Status:
A.
Open: Cygna asst coglete the review of the system test results for justifications of tray clamp behavior.
B.
Open: See Issue No.18.A for the status regarding the review of the system tests. Additional Cygna review of Ebasco clamp modelling procedure is required.
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- 19. FSAR Load Conbinations
References:
1.
CPSES FSAR, Section 3.8.4.3 2.
Gibbs & Hill Calculation Binder SCS-103C, Set 1 Sheets 14-19 3.
Gibbs & Hill Calculation Binder SCS-103C, Set 2 Sheet 32 4.
Transcripts of Cable Tray Hanger Design Verification meeting between TU Electric, Cygna Ebasco and Impell held at the CPSES site on January 26 and 27,1987 5.
C.R. Levine (TUGCO) letter to K.C. Warapius (Impell) No.
TSG-19043 dated July 2,1986 Summary:
Reference 1 defines the loads and load conbinations applicable to the design of cable tray supports. Cygna's review of the cable tray support designs indicates that only dead weight and seismic inertial loads are considered.
For supports installed in the Reactor Buildings, the loads associated with a LOCA may be applicable, including pipe whip, jet impingement, and thermal loads. Two support types within Cygna's review were designed for installation in the Reactor Building, Detail A (Gibbs & Hill Drawing 2323-El-0500-04-5) and Detail C (Gibbs & Hill Drawing 2323-El-0500-01-S. ) The design calculations for these supports, References 2 and 3 respectively, did not consider j
these additional loads.
Response
Information given in Reference 5 indicates that safe shutdown cable trays identified as pipe whip or jet impingement targets have either been relocated or shielded from the potential loads. Therefore, there is no need to evaluate the cable trays or supports for these loads.
TU Electric Comanche Peak Steam Electric Station LN.N i A Independent Assessment Program - All Phases 11111lll1lll111ll11lllllll1111 Job No. 84056 PRJ:RIL
05/08/87 Revision 13 Page 98 CABLE 1 RAY SUPPGtTS Review Issues List In Reference 4. TU Electric indicated that cable trays do not need to be evaluated for the thermal effects associated with normal operating temperatures and had developed a position relating to the effects of thermal loads due to the accident temperatures on support anchorages.
Status:
Open: Cygna review 'of TU Electric position on thermal loadings for cable tray / support systems is required.
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I
- 20. Differences Between the Installation and the Design / Construction Drawings without Appropriate Documentation
References:
1.
Gibbs & Hill, Inc., Support Layout Drawing 2323-El-0713-01-5 2.
Brown & Root Inc., Fabrication Drawing FSE-00159 3.
American Institute of Steel Construction, Inc., Manual of Steel Construction, 7th Edition 4.
Gibbs & Hill Support Layout Drawing 2323-El-0601-01-S 5.
Gibbs & Hill Support Layout Drawing 2323-El-0700-01-S 6.
Gibbs & Hill Cable Tray Support Design Drawings 2323-5-0900 series 7.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tray Support Walkdown Questions " 84056.026, dated August 23, 1984 l
8.
Communication Report between M. Warner, J. van Amerongen i
(TUGCO) and W. Horstman (Cygna) dated October 25, 1984 9.
Connunication Report between T. Webb, M. Hanburg (TUGCO) and W. Horstman (Cygna) dated October-18, 1984
- 10. Connunication Report between M. Warner, C. Biggs (TUGCO) and W. Horstman (Cygna) dated October 10, 1984
- 11. Brown & Root Procedure No. CEI-20, Revision 9, i
" Installation of Hilti Drilled-In Bolts" 12.
L.M. Pbpplewell (TUGCO) letter to N.H. Williams (Cygna),
" Comanche Peak Steam Electric Station Cygna Review i
Questions," dated Septenber 6,1984 TU Electric i
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KH. Williams (Cygna) letter to J.B. George -(TUGCO),
'" Cable Tray Support Walkdown Questions," 84056.021, dated August 16, 1984
- 14. K H. Williams (Cygna) letter to W.G. Counsil (TUGCO),
" Cable Tray / Conduit Support Review Questions,"
84056.089, dated October 21, 1985
- 15. Brown & Root Instruction QI-QAP-11.2-28, " Fabrication, Installation Inspections of ASME Component Supports, Classes 1, 2 and 3," Revision 29
- 16. Transcripts of Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna. Ebasco and Impell held at the CPSES site on January 26 and 27,1987
- 17. TU Electric Procedures TNE-FVM-CS-001, " Field Verification Method Unit 1 Cable Tray Hanger As-Builting and Design Adequacy Verification Program", Rev. 5. July 1,1986, and TNE-FVM-CS-003," Field Verification Method Unit 2 Cable Tray Hanger As-Builting and Design Adequacy Verification Program", Revision 1, October 18, 1986.
Supplemental Procedure for Unit 2 Walkdown, TNE-FVM-CS-019. " Selected Cable Tray Attributes Date: Collection Unit 2", Revision 1, September 3,1986 l
- 18. TU Electric, CPSES, " Generic Issues Report Evaluation and Resolution of Generic Technical Issues for Cable Tray Hangers". Revision 1 i
Summary:
Cygna performed walkdown inspections on 49 of the 92 supports within the review scope. Certain discrepancies between the as built support configurations and the design requirements were as noted below.
TU Electric
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Review Issues _ List N!i Support No. 481, Longitudinal Type A4 A.
1.
Single angles were installed.as braces in the longitudinal direction.. A pair of angles is required by the design drawing.
n 2.
The slopes of the upper longitudinal braces exceed i
I t te design limits.
3.
The working point locations for the lower longitudinal braces with respect to the beam elevation at the attachment to the hanger exceed the design limit..
i 4.
Th'e working points for all longitudinal braces, with respect'to the anchor bolts, exceed the design limits.
5.
The angle sections used for the longitudinal braces are inverted.
6.
The length of several of the Hilti Super Kwik bolts is insufficient to achieve the required enbedment.
B.
Support 2. 408, Type B4 w'
1.
The lower corner of the frame is modified by
, fa s
CMC 9916, Revision 1, to avoid interference with the 1"
CCW heat exchanger. This change document shows that i
b
.c 4" charnel sections are to be used for the prescribed modification. A 6" channel section was y
actually installed. The configuration of the notch, the weld pattern attaching the added menbers, the elevation of the top beam, and the Richmond Insert locations do not match the requirements of CMC 9916.
2.
The bottom beam is a C4 x 5.4 A C4 x 7.25 is required.
TU Electric Comanche Peak Steam Electric Station
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Support No. 649. Type A3 This installation uses concrete anchorage " Alternate Detail 1" (Gibbs & Hill design Drawing 2323-S-0903),
which requires the use of an L6x6x3/4. An L5x5x3/4 was installed.
D.
Support 2s. 722 and 2606, Detail "N", Drawing 2323-El-0601-01-S 1.
The working point for the brace, with respect to the anchor bolts, exceeds the design limit.
2.
For Support No. 2606, the length of the C6 x 8.2 beam is less than required.
3.
For Support No. 2606, the base angle is an L6x6x3/4, whereas the design requires an L5x5x3/4.
E.
Support Nos. 2992, 2994, 2005, 3017, 3021, 6654, Type A2 Reference-1 identified the above six supports as
~
follows:
"A2 (except all menbers shall be MC6 x 12),"
where L = 8'-3" (frame width), h = 4'-2" (frame height).
1.
The Cygna walkdown documented the installed hanger menber sizes, as listed below in Table 1.
Due to the presence of Thermo-Lag coating, which covers the entire bottom beam menber and part of the hanger menbers, Cygna was unable to determine the installed beam menber size.
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TABLE 1
- Cable Tray Support Hanger Menber Sizes Dimensions
- Med)er Sizes.
Flange Support Depth Width No.
(In)
(In)
Existing
- 2992 6
1-7/8 C6 x 8.2 2994 6
1-7/8 C6 x 8.2~
3005 6
1-7/8 C6 x 8.2 3017 6
1-7/8 C6 x 8.2 3021 6-1-7/8 C6 x 8.2 6654 6:
2-1/8 C6 x 13 Dimensions of the vertical channels (hangers) are based on measurements by Cygna. Menb er sizes are determined by selecting the channel i
type from Reference 3 which most closely matches the measured depth and flange width.
2.
The beam for Support No. 2992 was accessible and was found to be a C4 x 7.25 instead of the required MC6 x 12.
3.
For the Detail I hanger connections for Support No. 2992, the distance from the anchor bolt to the end of the base angle exceeded the design limit, and the gauge dimension was less than required.
l 4.
For Support No. 2992, a separation violation was noted between a Richmond Insert on the east hanger and a Hilti Kwik-bolt on an adjacent pipe support.
F.
Support P:3,,,,455, Type SP-8 1.
The brace connected to the wall on one side of the support is located outside of the bolt pattern on the base angle. The Detail "B" (2323-S-0903) type TU Ele:tric Comanche Peak Steam Electric Station L
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- Review Issues List connection requires the brace to be located between the two bolts. -
2.
The distance from the face of ~ the concrete wall to the support is less than that required on the design drawing.
3.
Gaps of up to 1/4" between the base angles and the concrete, without grout or shims, were noted.
4.
The distance between the top 1-1/4" Hilti Super Kwik 4olt on the north brace attachment and a 1/4" Hilti Kwik 4olt attaching the Thermo-Lag to the wall is less than required.
G.
Support Nos. 2998 and 13080, Special Type Supports These supports were installed on floor slabs with 2" topping.
The topping depth was not considered in selecting the length of the anchor bolts, and the required enbedment length was not achieved.
H.
Hilti Super Kwik 4olts Without Stars Section 3.1.3.1 of Brown & Root Procedure CEI-20 (Reference 11) requires:
Hilti Super Kwik 4olts shall be additionally marked with a." star" on the end which will remain exposed upon installation.
Twenty-eight of the cable tray supports inspected by Cygna required the installation of Hilti Super Kwik 4olts. Of these, only two supports had stars stamped on the bolts. The bolts on the remaining i
supports were not sth. ped.
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Contact Between the Component Cooling Water -(CCW) Heat Exchanger and Cable Tray Support flos. 332 and 408 See Issue No. 20.K.
J.
Support No. 2953, Detail "E".(Drawing 2323-El-0601-01-S)
This support is attached near the end of an enbedded strip plate. The distance from the end of the enbedded plate to a penetration through the concrete was less than the minimum distance required for the enbedded Nelson studs.
K.
Proximity Violations Between Cable Tray Supports and Other Components As a criteria for clearance between cable tray supports and other non-attached components, Cygna used a minimum of 1-inch separation. %is wa; based on the inspection criteria for pipe suppt. i.s (Reference 15), since no separation criteria was spuified in the cable tray installation inspection instruction. The separation violations found are the following:
Support No.
Violation Description 202 1/2" clearance between beam and insulation on pipe passing through support 299 Brace and hanger near top of support in contact with Thermo-Lag on conduits 332 0" clearance from CCW heat exchanger TU Electric Comanche Peak Steam Electric Station L
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Review Issues List 408 1/2" clearance between hanger and pipe passing through support. 0" clearance from CCW heat exchanger 605 1/8" clearance between end of beam and an HVAC duct 758 1/8". clearance between brace and pipe running parallel to support frame 765,766, 1" clearance between braces and 767 pipe passing through support 2986 Hangers are in contact with Therno-lag on an adjacent cable tray 3026 Thermo-lag on support beam is in contact with a pipe 6654 West end of bottom beam is in contact with a pipe 3016 Bottom beam is in contact with insulation on a pipe 3022 5/8 inch clearance between bottom beam and insulation on a pipe 13131 Fire protection on the cable tray is in contact with the rear bracket of the strut for a pipe support TU Electric Comanche Peak Steam Electric Station L
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- L.
Support No. 758 Detail "V" (Drawing 2323-El-0601-01-S) 2 1.
The north base angle for this support is shared with support no. 759. This attachment was not documented on the CMC affecting support no. 758.
2.
An anchor bolt spacing violation existed between one Hilti Super Kwik-bolt on the south hanger and a rod hanger from a fire sprinkler line.
M.
Su? port No.124. Type D2 1
1.
The channel sections installed were C6 x 10.5 and C4 x 5.4 for the bottom and top beams, respectively.
The design requires C4 x 7.25 sections.
.2.
The Richmond Insert pattern for the beam anchorage does not match that shown on CMC 1078, Revision O.
N.
Support No. 202, Type A4 1.
The channel sections installed were C4 x 5.4 for the b eams. The design requires use of C4 x 7.25 sections.
2.
The anchor bolt length for the south hanger attachment is insufficient to achieve required ed)edment.
O.
Support No. 479, Detail "C", Drawing 2323-El-0500-01-S
(-
The length of the overlap between the hanger and the i
base angle is less than required by design.
P.
Support No. 589, Type At l
1.
This support has an angle section added as a stiffener to the east C6 x 8.2 hanger, per CMC 2646, i
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Review Issues List Revision 5.
The installed weld pattern attaching i
the angle does not match that shown on the CMC.
l 2.
Each hanger is attached to the concrete using a single Hilti Super Kwik-bolt; however, the anchor bolts are not centered on the hanger as required by the design.
.Q.
Support No. 590, Type At 1.
This support has an angle section added as a stiffener to the east C6 x 8.2 hanger, per CMC 2646, Revision 5.
The installed weld pattern attaching the angle does not match that shown on the CMC.
2.
The depth of the notch provided to clear the tray rail exceeds the 3/4 inch limit given on CMC 2646.
+
R.
Support Ib. 605, Detail "A", Drawing 2323-El-0500-04-S l
l The cable tray is attached to the this support using l
Type II friction clamps. The gage distances for the bolts attaching the clamps to the support beam are not within the design limit.
S.
Support No. 638 Type SP-4 1.
The slope of the brace menber exceeds the design limit of 1.5:1.
2.
The brace is attached to the frame using a gusset plate, which is not allowed by the design.
3.
The working point of the brace with respect to the base angle is not within the design tolerance.
M&
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. CABLE TRAY SUPPORT 5 Review Issues List T.
Support No. 724. Detail "N", Drawing 2323-El-D601-01-S ~
i 1.
The length of the C6 x 8.2 beam was less than the required 6'-9" length.
2.
The L3x3x3/8 brace was attached to the incorrect side of.the gusset plate on the beam.
t 3.
An L6x6x3/4 was used'instead of the required L5x5x3/4 for the beam base angle.
4.
The anchor bolt types and locations do not agree -
with the requirements of CMC 155, Revision O.
U.
Support No. 763, Detail "K", Drawing 2323-El-0601-01-S
-The installed base plates are 1-1/4" thick. The design requires the use of 3/4" plates.
V.
Support No. 764, Detail "K", Drawing 2323-El-0601-01-S 1.
The installed base plates are 1-1/4" thick. The design requires the use of 3/4" plates.
2.
The tray attachment uses heavy-duty clamps with 1/2" A307 bolts attaching the clamp-to the tray. The distance from the end of the clamp to the bolt on
-ae clamp is less than required by the design.
3.
The channel used as a spacer between one tray and the support beam is not the required MC3 x 9' shape.
i l-W.
Support Nos. 765, 766, 767 Detail "J", Drawing 2323-El-D601-01-S 1.
The in-plane braces for these supports are attached directly to the supports' south base angles.
The r
design requires that the brace be attached to the i
hanger med)er, below the base angle.
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For Support No. 766, there is a spacing violation between one of the Richmond Inserts on the south hanger attachment and an adjacent Hilti Kwik 4olt.
4 3.
For Support No. 767, there is a spacing violation between one of the Richmond Inserts on the south hanger attachment and a rod hanger.
X.
Support No. 2602, Detail "W", Drawing 2323-El-0601-01-S Two non-seismic conduit supports were attached to this support at the east end of the W8 x 31 beam. The attachment of these conduits was not shown on applicable CMCs affecting this support.
Y.
Support No. 2986, Type A4 This support installation has one Hilti Super Kwik-bolt for each hanger anchorage. The design drawing (2323-S-0909) requires that the bolt centerlines be coincident with the hanger centerlines, however the bolts are up to 1/4 inch off center.
l Z.
Support No. 3026 Type SP-4 The north beam was a C4 x 5.4 section. The design requires the use of a C4 x 7.25 section. Since the other menbers were covered with Thermo-Lag, their sizes could not be determined.
AA. Support No. 3028 Type D1 1.
The east hanger is composed of two separate pieces of channel, a C6 x 8.2 and a C6 x 10.5, butt-welded together approximately 11 inches above the cable trays.
2.
The hanger attachment to the concrete slab uses o'*
Richmond Insert and one Hilti Kwik-bolt. The TU Electric Comanche Peak Steam Electric Station L
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05/08/87 Revision 13 Page 111 CABLE TRAY SUPPORTS Review Issues List location of hanger with respect to the bolts does not meet the design requirements.
)
BB. Support No. 3134, Detail "11", Drawing 2323-5-0905 1.
The beam length is 6 inches greater than that shown on CMC 8585, Revision 3.
2.
The longitudinal braces were L3x3x3/8 sections. The design requires the use of L3-1/2x3-1/2x3/8 sections.
3.
Two conduits were supported by rod hangers attached to the base angle for the east hanger, these conduits were not shown on any applied)le change documents.
CC. Support No. 5807 Type Longitudinal At 1.
The slope of the longitudinal braces are not with design tolerance.
2.
The L3x3x3/8 sections for the braces are inverted.
3.
The weld between the west brace and the hanger does not provide the required minimum weld length.
4 The welds between the gusset plates and the base angles are not per design requirements.
5.
The working points of the longitudinal braces with respect to the anchor bolts are not within the design tolerance.
6.
The location of the TS6x6 from the attached pipe support does not correspond with the location shown on CMC 80294, Revision 0.
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- 7. l Based on the indicated bolt length and the measured bolt projections, several of the Hilti_ Super Kwik 4cits do not provide sufficient embedment.
l DD. Support No. 332 Detail "A", Drawing 2323-El-0700-01-S 1.
The concrete edge distance for the Hilti expansion anchors exceeds the 10 inch limit required by DCA 4897, Revision 0.
i 4
2.
Separation violations between top anchor bolt and the anchor bolts for pipe support CC-2-01-003-A331 are not documented.
i EE. Support No. 629. Type SP-7 with brace i
.The slope of the longitudinal brace is not.within
[
1.
the range allowed by the design.
2.
The gusset plate attaching the brace to the beam is located 2 inches from the end of the beam.
The design requires the gusset plate to be flush with the beam end.
FF. Support tb. 631, Type SP-7 This support is attached to an enbedded strip plate. A j
separation violation exists between the plate edge and a 1 inch diameter Hilti Super Kwik-bolt.
!~
GG. Support No. 720. Type SP-7 Separation violations between bottom Hilti Super Kwik 4olt and the anchor bolt on an adjacent support is i
not documented.
I l
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05/08/87 Revision 13 Page 113 CABLE 1 RAY SUPPORTS Review Issues List HH. Support No. 734, Detail "H", Drawing 2323-El-0601-01-S The top and bottom beams are not located within the design location tolerance.
II. Support No. 790, Type SP-7 This support is located on the surface of an opening in a concrete wall. An enbedded plate is located 8 inches from the edge of the opening. The separation between the expansion anchors for the support and the enbedded plate does not meet the requirements of Gibbs & Hill specification 2323-SS-30.
(See Issue No.17.F. )
JJ. Support %. 2920. Type SP-7 with brace 1.
This support uses a gusset plate to attach the longitudinal brace to a horizontal base angle.
This connection is not allowed by the design drawing.
2.
The location of the brace with respect to the anchor bolts does not meet the design requirements.
KK. Support No. 3016, Detail "F", Drawing 2323-El-0601-01-S 1.
The bolt hole end distances on the base plate exceed the design limit of 3 inches.
2.
The center anchor bolt is a 1 inch diameter expansion anchor. The design requires a minimum 1-1/4 inch diameter bolt.
LL. Support No. 3022. Detail "F", Drawing 2323-El-0601-01-S The locations of the Richmond Inserts do not agree with those shown on CMC 4534.
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Potential Root Causes of Construction Discrepencies.
As sununarized above, Cygna has noted a large number of construction discrepancies in the cable tray supports within the review scope. Cygna is concerned about the manner in which these discrepancies will be addressed in the current reevaluation program. Specifically, Cygna raised the following questions during the meeting documented in Reference 16:
1.
After the as4uilt drawing development is conpleted, will an effort be made to compare these drawings with the original design drawings to identify a potential root cause of the construction deficiencies?
2.
Has an evaluation been performed to establish the root cause of the drawing quality problems?
~
3.
What changes in project procedures have been made to prevent a reoccurrance of similar problems in future work at CPSES?
Response
The design verification of cable tray supports is based on the as-built configuration of the supports. The ase uilt walkdown procedures are specified in Reference 17. All concerns associated with Issue Nos. 20.A through 20.J and 20.L through 20.LL are addressed through the design verification of the as4uilt support configurations.
Issue t'
No. 20.K. proximity violations between supports and other components, has not yet been addressed.
Per Reference 18, I
Appendix A20 and Reference 16. TU Electric is currently in the process of developing criteria to determine the required separations between the cable tray systems and other conto.,nts.
Cygna understands that a 100% hardware / installation reverification is being performed and, as such, the generic implications of these discrepancies are no longer a concern TU Electric Comanche Peak Steam Electric Station L
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with regard to cd)1e trays. The root cause of these specific findings has been considered, but not formally addressed by the Project.
(Reference 16.)
Status:
All issues regarding as4)uilt discrepencies (A-J, L-LL) are closed based on the current support as4)uilt prograsu However, due to the state of the construction of CPSES, certain components on a nud>er of supports are no longer accessible for inspection (i.e., hidden or inaccessible attributes).
In Reference 16, TU Electric indicated that the developnent of a uniform approach for the evaluation of hidden attributes is in progress. Cygna will review this approach when it becomes available.
Based on a review of the as4)uilt procedures (Reference 17)
Cygna raised several concerns. These are discussed in Issue No. 33.
Issue Na. 20.K is open pending receipt of proximity criteria.
Issue No. 20.MM is open.
4 l
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Design Control
References:
1.
Gibbs 8 Hill Drawings 2323-El-0601-01-5, 2323-El-0700-01-S, 2323-El-0713-01-S 2.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tray Support Design Review Questions," 84056.022, dated August 17,1984,. questions 1, 2, and 6 3.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tray Support Design Review Questions," 84056.025, dated August 21, 1984, question 1 4.
Gibbs & Hill Cable Tray Support Design Drawings 2323-S-0900 Series 5.
Gibbs & Hill Calculations for Support Nunbers 3025, 3028, 2861, Cygna Technical File 84056.11.1.225 6.
L.M. Popplewell (TUGCO) letter to N.H. Williams (Cygna),
" Responses to Cygna Review Questions," dated Septenber 4, 1984, with attached calculations 7.
Gibbs & Hill Calculation Binder 2323-SCS-101C, Set 3, Sheets 206, Revision 6 8.
L.M. Popplewell (TUGCO) letter to N.H. Williams (Cygna),
" Response to Cygna Design Review Questions," dated Septenb er 11, 1984, with attached calculations 9.
Gibbs & Hill Calculation Binder 2323-SCS-101C, Set 5 10.
Gibbs & Hill Drawing 2323-S-0901, Revision 4 11.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tray Support and Electrical Review Questions,"
84056.019, dated August 10, 1984, questions 2.1 and 2.2 WA TU Electric Comanche Peak Steam Electric Station L
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- 12. Gibbs & Hill Drawings 2323-El-0601-01-5, 2323-El-0700-01-S, and 2323-El-0713-01-5
- 13. Gibbs & Hill Specifications 2323-ES-19. Revision 1 l
" Cele Tray Specification" 14 Gibbs & Hill Calculation Binder 2323-SCS-111C, Set 8
- 15. Communications Report between P. Huang (Gibbs & Hill) and J. Russ (Cygna) dated June 13, 1984 L
16.
L.M. Popplewell (TUGCO) letter to N. Williams (Cygna),
" Comanche Peak Steam Electric Station Cygna Review Questions " dated August 27, 1984 with attachments 17.
R.E. Ballard (Gibbs & Hill) letter to J.8. George (TUGCO), " Cele Tray Supports Cygna Phase 4 Audit Activities," GTN-69377, dated August 24, 1984, with attachments 18.
L.M. Popplewell (TUGCO) letter to N. Williams -(Cygna),
l
" Comanche Peak Steam Electric Station Cygna Review Questions," dated Septenber 11, 1984, with attachments
- 19. Gibbs & Hill Calculations Binder 2323-SCS-111C, Set 7
- 20. TUGC0 Instruction CP-EI-4.0-49, Revision 1 4
- 21. C21e Tray Thermo-Lag Evaluation, Safeguards Building, Elevation 790'-6."
Cygna Technical File l
84056.11.1.1.315 22.
N.H. Williams (Cygna) letter to J.8. George (TUGCO),
" Cele Tray Support Review Questions," 84056.041, dated Fe ruary 12, 1985 e+
- 23. Communications Report bltween M. Warner (TUGCO) and N.
1 Williams et al. (Cygna), dated Feruary 27, 1985 i
i 1
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' Review Issues List 24 KH. Williams (Cygna) letter to V. Noonan (USMC),
" Response to IRC Questions,"'83090.023, dated March 8, 1985
- 25. Brown & Root Cable Tray Hanger Assenbly Drawing FSE-00159
- 26. Gibbs & Hill Design Procedure DP-1, " Seismic Category I Electrical Cable Tray Supports," Revision 0, dated 6/11/84 27.
EH. Williams (Cygna) letter to W.G. Counsil (TUGCO),
" Cele Tray / Conduit Support Review Questions,"
84056.089, dated October 21, 1985 28.
N.H. Williams (Cygna) letter to J.8. George (TUGCO),
" Cable Tray Support Review Questions," 84056.027, dated August 27, 1984
- 29. Ebasco Procedures SAG.CP4, " Seismic Design Criteria for Cele Tray Hangers for CPSES Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES Unit 2", Revision 6 1
- 30. TU Electric Procedures TNE-FVM-CS-001, " Field Verification Method Unit 1 Cable Tray Hanger As-8uilting and Design Adequacy Verification Program", Revision 5, July 1,1986, and TNE-FVM-CS-003," Field Verification Method Unit 2 Cele Tray Hanger As-8uilting and Design Adequacy Verification Program", Revision 1, October 18, 1986. Supplemental Procedure for Unit 2 Walkdown, TNE-FVM-CS-019, " Selected C&le Tray Attributes Data Collection Unit 2", Revision 1 Septenber 3,1986.
- 31. Ebasco Introduction, " General Instructions for Cable Tray Hanger Analysis for CPSES Nos 1 and 2", Revision 4 I
32.
Impe11 Instruction PI-02, " Dynamic Analysis of Cele Tray Systems". Revision 5 TU Electric 4
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- 33. Transcripts of the Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna. Ebasco and Impell 1
held at the CPSES site on January 26 and 27. -1987 34 Impe11 Calculation M-39, " Side Rail Extension Study",
Revision 0 Summary:
A.
Tracking and Consideration of Design Changes-During the course of the design and construction of cable tray supports, a large nusber of design change documents (DCAs and CMCs) have been issued that affect the support designs. These design changes can be grouped into two categories. Generic design changes are l
1ssued against a Gibbs & Hill support design drawing (e.g., 2323-S-0901) and nay affect all installations of one or more generic support designs.
Individual design changes are issued against a support layout plan (e.g.,
2323-El-0601-01-S) and affect one or more individual support installations.
Cygna's review has identified several areas where oversights or errors may occur in the handling of these design changes. These may be due in part to the large nunbers of design changes which have not been incorporated in the design drawings.
1.
Generic Evaluations In the process of performing generic evaluations of support design adequacy (e.g., the inclusion of base plate flexibility in response to IE Bulletin 79-02, the Working Point Deviation Study, the evaluation of the effects of weld undercut / underrun, etc.), Gibbs
& Hill based their calculations on the oi'iginal support designs without considering the effects of all applicable generic design changes.
(Reference 27.)
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Case by-Case Design Adequacy Reviews In some cases, as a result of the generic studies discussed above, the design limits for a support type were made more restrict 1ve than those of the original design.
In order to qualify existir.g supports which had been specified based on the original design limits, a case by-case design adequacy review was performed for all individual supports which exceeded the revised design limits.
These reviews were based on the as-designed configurations for the individual supports, and did not include the effects of applicable individual design changes.
(Reference 27.)
3.
Tracking of Design Changes Affecting Individual Supports The design changes for individual supports are tracked by the cable tray support plan drawing nunber rather than by the support nunber.
In order to locate all design changes affecting a given sup-port, one must manually search through all design changes affecting all supports on the applicable support plan. Cygna has observed that some support plans have over 200 design changes outstanding.
In i
order to expedite this effort, the TUGC0 Field Structural Engineering Group (FSEG) maintains a list of design changes sorted by individual support nunb er.
This list is not a controlled document, and Cygna's review noted several discrepancies between l
the design changes listed for individual supports and those located by Cygna through a search of i
design change documents at the Document Control Center.
It is Cygna's understanding, however, that this informal log is relied upon by the field engineer to determine which design changes should be I
considered in their evaluations of field change requests.
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4.
Design changes Used For Q.C. Inspectors-1 A discussion with TUGC0 cable tray support installation Q.C. personnel (Reference' 23) indicated that the method of locating design changes for support inspection purposes was very cunbersome and placed an undue burden on the inspectors in assenbling inspection packages. TUGC0 Q.C.
. indicated that the inspectors typically relied on the list of design changes included in the Brown &
Root construction package as a basis for inspection without independently verifying the completeness of the package.
5.
Adequacy of Design Review l
l Cygna has noted instances where the design review for the verification of design changes may have been inadequate. The design changes allowed deviations from the original design that invalidated certain assumptions on which the original design was l
based.
However, the design review did not note this and did not assess the impact of the change on the design basis.
In other cases, the design review did not assess the impact of the change on all components of a support that would be affected.
Exanples of this include:
o Pase angles are designed assuming a minimum distance of 3" from the bolt hole to the end of the angle. This distance is used in the calculation of the resisting noment arm when a bending moment is applied to the base angle.
CMC 1970 reduced this distance to a minimum of
/
1-1/4".
The design review for this CMC did g
not consider the impact of this reduction on the anchor bolt designs.
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Cable tray supports are designed for a frame width based on a minimum distance of 3" from the outside tray rail to the inside of the flange of the hanger.
(See Issue No. 28. A. )
CMC 2646 allows the hanger to be notched so that the tray rail actually overlaps the inside flange of the hanger. this can result in cable tray supports which do not meet the minimum width required by the design. The design review for this CMC only addressed the reduced section properties at the notch without considering the effect on the support width.
o Cable tray supports are designed to act as a system, with the cable tray acting as a link between supports.
(See Issue No.10.) CMC 93450 allows gaps between the cable trays and the clangs attaching them to the supports.
The frictional force between the clamps and the trays, which is required to prevent relative axial displacement between the trays and the supports, is eliminated by the gap.
The design review for this CMC does not address the effect on the system behavior of the cable trays.
(See Issue No.18. )
o Cable trays are qualified for an 8'-0" maximum span.
(See Issue No. 25.B.) DCA 1594 provides an installation location tolerance for the supports, resulting in a maximum spacing of 9'-0" between supports.
The design review for this CMC does not consider the effect of the increased span on the cable tray (talification.
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Criteria Violations in Individual Support Specifications on Support Plans In the generic design of cable tray supports, support dimension and loading limitations are determined for each support type. These limitations are typically stated in tre design calculations, but are not shown on the generic support design drawings.
(Reference 4.)
The dimensions for each support are specified in a descriptive block on the support plans (Reference 1),
and the loading is indicated by the supported tray width shown.
The tray supports listed below were identified as having loadings or support geometries which exceeded the design limitations.
Prior to the Cygna review, justifying documentation did not exist for the following individual support designs.
1.
Support Nos. 3025, 3028, 2861, Type D.t Drawing 2323-El-0713-01-5 specifies these supports as Type D1 (except beam to be MC6 x 16.3), L =
11'-9", h = 4'-2", and shows a tray width of 78".
The design calculations for Type D1 supports limit L < 8'-0" and tray width to 48".
2.
Support No. 2607. Type A.
g Drawing 2323-El-0601-01-S specifies dimensions of L
= 2'-9" and h = 4'-6" for this support. The design calculation for this support type limits h < 2'-4".
3.
Support No. 657 Type A.
1 Drawing 2323-El-0201-01 specifies this support as Type A L = 7'-0",.h = 2'-0".
The design g
calculation for this support type limits L < S'-0".
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Support No. 734, Detail "H", Drawing 2323-El-0601-01-5.
This drawing specifies that one beam is to be an MC6 x 15.1, rotated 90* from its normal orientation..The support design requires the use of C6 x 8.2 beam sections. Thesectionmogulusof MC6 x 15.1 about its weak axis,1.75 in, is smaller thgn that of C6 x 8.2 about its strong axis, 4.38 in. Therefore, this support should be reevaluated for vertical loads.
Rotating the MC6 x 15.190* from its normal orientation significantly increases the longitudinal stiffness of the support. This rotation, together with CMC 00164, which requires the use of a " heavy duty clany," can introduce significant longitudinal loads to the support. The support design requires the addition of a longitudinal brace if longitudinal loads are to be resisted.
5.
Support No. 3011, Type SP-6.
Drawing 2323-El-0713-01-5 specifies dimensions of L
= 8'-9" and h = 4'-6".
The design calculation for this support type limits L < 6'-0".
6.
Support Nos. 2992, 2994, 3005, 3017, 3021, 3111, 6654, Type A '
2 Drawing 2323-El-0713-01-S specifies dimensions of L
= 8'-3* and h = 4'-2", and shows a tray width of 78".
The design calculation for this support type limits L < 6'-0" and the tray width to 48".
7.
Support ts. 95 and 112, Type SP-7.
Drawing 2323-El-0700-01-S specifies these supports as Type SP-7, L = 5'-1", and shows a tray width of ML TU Electric Comanche Peak Steam Electric Station A
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The design calculations for Type SP-7 limits the tray width to 30".
8.
Support No. 758, Detail "V", Drawing 2323-El-0601-S.
Drawing 2323-El-0601-01-S specifies this support as Detail "V", h1 = 8'-4", h2 = 7'-3", h3 = 4'-0",
in = 5'-9", 12 = 2'-3",
a = 2'-6", and shows a tray w'dth of 66".
The design for the support detail limits the tray width to 60".
9.
Support Nos. 765, 766 and 767, Detail "J", Drawing 2323-El-0601-01-S.
Drawing 2323-El-0601-01-Ss[ecifiesthesesupports as Detail "J", L = 8'-6", h1 = 10'-10", h2 = 9'-6",
h3 = 3'-6", and shows a tray width of 66".
The design for the support detail limits the tray width to 48".
Additionally, Gibbs & Hill was not consistent in t
est211shing controlling criteria (i.e., support dimensions, tray width, etc.) in support designs. As an example, in several support designs, the support frame was designed for a particular height and width while the anchorages were designed using reactions from a frame with a different height and width.
The lack of a single limiting configuration may affect the support dimensions as shown on the cable tray support plans.
Within Cygna's scope, support types E, SP-6 and SP-8 are 4
I affected.
1 C.
Consideration of As-Built Support Conditions in Generic Reviews Which Require a Case 4y-Case Review 1.
The SP-7 weld underrun analysis considered 5/16" fillet welds which are specified on the design drawings.
% wever, the FSE-00159 fabrication TU Electric Comanche Peak Steam Electric Station L
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In addition, the underrun analysis did not consider the effects of any design changes to the supports which were reported in CMCs and DCAs.
(See Review Issue 21. A.)'
2.
The Working Point Deviation Study did not include the effects of all applicable design changes.
(See Issue 2. 12.)
D.
Inconsistencies in the Evaluation of Cele Tray Supports For Thermo-lag Application 1.
Tray cover weights were not included in the development of the allowable span length tables (References 19 and 20) for fire-protected cable trays.
2.
Cygna believes that longitudinal supports are not evaluated for the added weight of fire protection.
Cygna noted evidence of the above in the fire protection reviews for cable tray segment T1205BD07. A longitudinal support (type L-A ) was 1
assumed to provide transverse restraint in the fire protection calculation. The calculated transverse load was cogared to an assumed design capacity, but no longitudinal load was calculated. The original design for this support type assumes that only longitudinal restraint is provided.
Note that the calculations (Reference 21) reviewed by Cygna had '
not been design-reviewed at the time they were received from TUGCO.
?.
Gibbs A Hill performed calculations to determine the design capacity for supports to use as a comparison to the tray loads including fire protection.
(Reference 21.) A tributary span of 9'-0" was assumed. The actual design span was 8'-6";
therefore, the Reference 21 calculations overestimated the support design capacity.
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For several cable tray segments within Cygna's review scope, the tray weight, including fire protection, exceeded the design limit of 35 psf by up to six percent, but engineering evaluations were not performed as required by Reference 20. See Reference 27, question 3, for a listing of the affected tray segments.
5.
For tray sognent no. T130SCA46, side rail extensions were installed, but a special evaluation was not provided as required by Reference 20.
(See Issue No. 25.C.1. )
Cygna has requested additional information on the fire protection evaluation process in Reference 27.
E.
Tray Spans Between Supports Used In the Original Support Layout 4
1.
Reference 13 indicates that cable trays are to be '
designed and qualified for 8'-0" transverse and vertical spans. Reference 10, Note 13, allows a location tolerance for supports of i 1/2 of the Richmond Insert spacing parallel to the tray, and limits the maximum spacing between supports to 9'-0."
Gibbs & Hill cable tray support design calculations assume a maximum tributary span of 8'-6 " to account for a support spacing of 8'-0" on center and an erection tolerance of i 6."
Cygna reviewed the tray support plans for segments within the review scope (Reference 12) and noted 15 locations where the as-designed tray spans exceeded 8 ' -0".
Cygna's walkdown of these tray segments identified 5 locations where the as built tray spans exceeded 9'-0".
(See Reference 11.) This indicates that the design and installation limitations for support spacings may not have been complied with in TU Electric 4
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2.
Reference 13 indicates that cable trays are to be designed and qualified for 40'-0" longitudinal spans. Longitudinal support design calculations assume a maximum longitudinal tributary span of 40'-0".
For several supports within Cygna's review, the support plan drawings (Reference 12) showed these supports to have tributary spans greater than 40'-0".
(See Reference 11.)
In addition, several horizontal tray segments were not provided with any longitudinal supports.
(See Reference 11.) This indicates that the design limitations for the location of longitudinal supports may not have been conplied with in the preparation of support layout drawings.
F.
Lack of Calculations For Change %tices Cygna has noted several design reviews of change notices where the CVC was marked to indicate that new or revised calculations were not required. Cygna considers some of the design changes to be significant, such that calculations should have been provided to justify their acceptability.
In some cases, calculations marked "for
(.,
reference only" are attached to the CMC which the reviewer had accepted without new or revised calculations.
G.
Design Calculation Retrievability and Completeness During the course of the Phase 2 and 4 reviews, Cygna experienced difficulty in assenbling complete support design calculation sets. Cygna noted that Gibbs & Hill has similar difficulty. The following examples illustrate Cygda's concerns.
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In Phase 2 of Cygna's IAP, Cygna requested an f
evaluation of the effect of torsion in the C4x7.25 beams on the support design adequacy.
Gibbs & Hill provided calculations (Reference 14 Sheets 28-33) which evaluate torsion in the beams. These calculations were performed in 1982, but were not i
included in the indicated calculation binder (the cover sheet for Reference 14 indicated that the total nunber of sheets was 6). Se sequent to i
Cygna's review of these calculations, they were added to form Revision 1 of Reference 14 2.
Cygna requested a list of all calculations relevant to several generic support designs.
(Reference 15.) Gibbs & Hill provided a list of calculation binder and sheet nusbers for each support type.
The review of these calculations by Cygna indicated that there were additional calculations relevant to the support designs which had not been included on the list. For example, the Working Point Deviation l
l Study involved several supports listed in Reference 15, but was not referenced in Gibbs & Hill's response.
The difficulties in identifying and locating all calculations pertinent to a support design may be in part attributable to Gibbs & Hill's methods of controlling structural design calculations. Cygna observed that, as a general rule, Gibbs & Hill did not revise or supersede older calculations.
In performing generic studies (e.g., Working Point Deviation Study, weld undersize / undercut, evaluation of torsional stresses in menbers, etc.) or performing design reviews i
for generic design changes, the new calculations evaluate only the effects of the changes. These new calculations may referenca the previous calculations as a source of data, but the previous calculations are not superseded by the new calculations, nor are they revised to reflect the results of the design change or generic TU Electric Comanche Peak Steam Electric Station b
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Hence, it is extremely difficult, from reviewing an original design criculation, to determine if it is still applicable to the support design.
It is also difficult to identify and locate generic study or design change review calculations that are applicable to the support design.
j H.
Lack of Controlled Design Criteria At the initiation of this review, the cable tray support design criteria used by Gibbs & Hill consisted of a calculation set in a structural calculation binder.
(Reference 9.).Cygna's review of this document indicated that insufficient detail was given to assure that cable tray support designs were performed in a consistent manner and that the designs satisfied the requirements of the CPSES FSAR. Examples of the impact of an incomplete design criteria include:
1.
Cygna has noted instances where the field design i
j review group did not utilize the proper criteria to i
evaluate support adequacy. The evaluations for fire protection compared the as-built support load to a i
design load consisting of the allowable distributed load over a 9'-0" tributary tray span. Since the maximum tributary span assumed in the current design calculation is 8'-6", the use of a 9'-0" span overestimates the allowablo load.
2.
Cygna has asked what supplements to the 7th Edition of AISC Specifications were comitted to in the l
FSAR. No evidence was found to indicate that proper direction was given to design engineers to utilize the requirements of any supplements to which CPSES was committed.
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Differences Between Design Drawings and Assenbly Drawings Cygna performed a review of the cable tray support assed)1y drawings (Reference 25), which are used for construction purposes, and evaluated the accuracy of these drawings via a comparison with the applied)1e design drawings.
(References 1 and 4.)
Numerous drawing discrepancies were noted, which included:
o Incorrect is1d sizes specified for fillet welds.
(See Review Issue 16. A) o Incorrect weld patterns o
Incorrect med)er sizes specified in the " Bill of Material" o
Incorrect anchor bolt connection details o
Incorrect support dimensions i
o Med)ers that are not required by the design For a detailed listing of the individual discrepancies, see Reference 24.
Response
A.
The design verification of cd)1e tray supports is based on the as4)uilt support configuration, as specified in Section III.2 of Reference 29 and Reference 30. Since all supports have been as4)uilt there is no need for the previously issued design change documents except for the disposition of the effects of hidden attributes.
B.
This is no longer an issue since all of the supports are now individually design verified.
C.
This is no longer an issue since the results of the Gibbs & Hill generic studies are no longer used.
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All cable tray supports will be individually evaluated, considering the weight of Thermo-lag, if applicable.
1.
Per Section III of Reference 29, Ebasco considers the as-built weight of the cable tray, including tray covers. The cable tray weights used by Impell, l
Reference 32, Section 3.2.2, include the weight of the covers.
2.
The design verification of cable tray supports include all support types (transverse, longitudinal and multi-directional). Thermo-lag weights are included as applicable.
3.
The original Gibbs & Hill calculations for cable tray supports considering Thermo-lag are no longer used.
4 The cable tray system evaluation is based on the as-built tray and cable weights.
However, Reference 29 and 32 indicate that if the as-built weight of the tray is unavailable, a normal weight of 35 psf should be used. This raises several questions:
a.
In what cases are the as-built cable fill weights unavailable? Are there any outstanding issues relativa to the accuracy or completeness of the cable and raceway schedule?
b.
Since Cygna has found instances where the actual tray weight exceeded 35 psf, what is the justification for using 35 psf?
In Reference 33, the response to these questions was deferred until the interface with the Electrical Action Plan has been resolved.
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Ibasco includes the weight of the cable tray siderail extension in calculating the tray weight.
(Reference 29.)
Igell provided an evaluation (Reference 34) indicating that the impact of sidera11 extensions in the cable tray system a
evaluations is not significant. Cygna believes that the weight of the extensions should be considered.
E.
Cable tray supports are evaluated based on the as built tray spans. Span length violations in the original support layout are, therefore, no longer an issue. For a discussion of the evaluation of the acceptability of the cable trays, see Issue No. 25.
F.
Since 100% of the cable tray supports are being design verified, calculations associated with the review of previously issued design changes are no longer used.
TU Electric, per Reference 33, is developing a procedure to control the review of any design changes that say be generated in the future.
G.
The original Gibbs & Hill and TUGC0 design calculations are superceded by the current cable tray support design verification effort.
i H.
Both Ebasco and Impell have developed sets of design criteria, project instructions and procedures to assure
=-
consistency and cogliance with the CPSES FSAR for all calculations associated with the cable tray support design verification program.
I.
The cable tray support design verification program is based on the as-built support drawings.
No reliance is placed on the original Brown & Root assenbly drawings.
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05/08/87 Revision 13 Page 134 CA' ALE 1 RAY SUPPGtTS Review Issues List Status:
- A.
Open: The design verification relies on previously issued design change documents to aid in the specific.ation of. support hidden attributes. TU Electric will provide a uniform approach to the hidden attributes prd)1em at a later date.
+
8.
Closed: Since all of the supports are being individually design verified.
C.
Closed.
D.
1.
Closed.
2.
Closed.
3.
Closed.
4.
Open.
5.
Open: Cygna has concerns regarding Impell's method of justification for not including the weight of the siderail extensions. See the Status for Issue No.
21.H regarding differences in the assumptions used by each consultant.
E.
Closed for the evaluation of the cd)1e tray supports.
See Issue No. 25 for the evaluation of the cd)1e trays.
F.
Open: As part of the review of design control issues, Cygna will be reviewing key aspects relating to design control procedures.
G.
Closed.
I H.
Open: Cygna's review of the design criteria and work instructions used for the cd)1e tray support design verifications has noted differences in the analysis methods and assumptions used by the two consultants.
4 TU Electric
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05/08/87 Revision 13 Page 135 CABLE 1 RAY SUPPGtTS Review Issues List Such differences are noted in the applicable locations within the Review Issues List.
Cygna is also reviewing the criteria and analysis methods used individually by each consultant to assure consistency with the approach taken within their individual work scope.
I.
Closed.
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Design of Support No. 3136, Detail "5", Drawing 2323-S-0905
References:
1.
Gibbs & Hill Calculation Binder SAB-1341, Set 3 Revision 0 2.
Communication Report between B.K. Bhujang (Gibbs & Hill) and N. Williams, et al. (Cygna) dated October 20, 1984 3.
Gibbs & Hill Calculation Binder SAB-1341, Set 3, Revision 1 4.
N.H. Williams (Cygna) letter to W.G. Counsil (TUGCO),
" Cable Tray / Conduit Support Review Questions",
84056.089, dated October 21, 1985 5.
Transcripts of the Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna, Ebasco and Impell at the CPSES site on January 26 and 27,1987 Susumary:
Support No. 3136, located at elevation 790'-6" at the Auxiliary Building / Safeguards Building boundary, is enbedded in a fire wall.
In reviewing the design calculations for this support (Reference 1), Cygna noted several concerns. A list of Cygna's questions was provided (Reference 2 Attachment A) to Gibbs & Hill for their revie.:. These concerns included:
o Justification for not considering tornado depressurization loads was not provided.
o The original cable tray support is Seismic Category I, while the fire wall is Seismic Category II.
Justification for this conflict in design classification was not provided.
o Several errors were found in the finite element model and in the calculations.
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Response
During the discussions in Reference 5, Ebasco provide the following response:
Isolated cases of cable tray hangers supported from Category-II structure are identified and evaluated on a case 4y-case basis. Seismic Category II walls will be qualified by the SWEC Civil Structural Corrective Action Program.
Support No. 3136 is in Ebasco's scope of work. For design verification of this support, the Seismic Category II wall is not assumed to provide support for the cable try system, however, the inertial effect of the Category II wall is l
considered in a new finite element model. Tornado depressurization load effects from the Category II wall will be addressed by SWEC in the Civil Structural Corrective Action Program.
Ebasco has indicated that the evaluation of Support No. 3136 is currently in progress. Attachment loads will be reported to SWEC.
Status:
Open. Cygna will review the calculations for the support when they are finalized. Cygna will also review SWEC's treatment of Category II walls in the Civil Structural Corrective Action Program, i
i l
l 1
1.
i TU Electric I
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~
- 23. Leading In STRESS Models
References:
1.
Gibbs & Hill Conputer Output Binder 2323-DMI-5P 2
Gibbs & Hill Calculation Binder 2323-SCS-215C Set 2 I
3.
Gibbs & Hill Drawing 2323-5-0901, Revision 4 4
Cygna Energy Services, " Independent Assessment Program Final Report - Volume 1, for Texas Utilities Services Inc., Comanche Peak Steam Electric Station," Report No. TR-83090, Revision' 0 5.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for Comanche Peak SES No. I and 2",
Review 5.
Summary:
For the design of standard support Cases A, Bj, Cj and Dj, j
where i = 1 to 4, finite element analyses were performed (Reference 1) using the program STRESS. Single beam elements were used to model the horizontal menbers (b eams). The analytical results may be inaccurate due to the following concerns:
A.
Tray Load Application Point Tray loads were applied at the beam / hanger intersection, rather than within the span of the beam where the tray is physically located. Modelling the load placements in this fashion eliminates the effects of bending and torsion due to vertical loads on the beams, and for Cases Dj, will totally remove the load applied at the wall connection from the support.
(See Cygna's Phase 2 (bservation CT-00-03 in Reference 4.)
8.
Tributary Load Calculations l
The applied loads are calculated based on an 8'-0" tributary tray span. The actual design span is 8'-6" if TU Electric Comanche Peak Steam Electric Station L
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Review Issues List j
installation tolerances are considered.
C.
Modelling of Support Frame Height The support design drawings (Reference 3) specify the support frame heights as the distance from the bottom of the concrete to the top of the C4x7.25 beam. The models l
considered this distance to be from the concrete to the centerline of the beam, thus underestimating the support height by two inches. This error is also found in the related design calculations for the trapeze supports.
Response
A.
For response spectrum analyses of cable tray supports, both Igell and Ebasco generate cable tray system models which have the tray loads applied to the support at the tray centerline location.
For the static and equivalent static analyses of cable tray supports, Reference 5. Attachments B1 and B2, Ebasco applies the vertical and longitudinal loads from the tray to the support at the cable tray clamp locations.
However, the horizontal transverse load from the tray is applied to the support at the beam to hanger l
intersection point.
This may result in an l
underestimation of the axial load in the beam.
B.
The current cable tray support design verification effort do.s not use the results of Gibbs & Hill's support t.nalyses. Therefore, this is no longer an issue.
C.
See response for Issue Ib. 23.B.
Status:
A.
Open pending cogletion of Cygna review of Ebasco study.
B.
Closed.
C.
Closed.
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.l CABLE 1 RAY SUPPGtTS Review Issues List 24 Design of Flexural Menbers
References:
1.
N.H. Williams (Cygna) letter to J.B. George (TUGCO),
" Cable Tray Support Review Questions," 84056.031, dated August 31, 1984 2.
L.M. Popplewell. (TUGCO) letter to N.H. Williams (Cygna)
" Comanche Peak Steam Electric Station Cygna Review Questions," dated Septenber 28, 1984 3.
Communication Report between E. Bezkor et al. (Gibbs &
Hill) and M. Engleman et al. (Cygna) dated April 11,1985 4.
Gibbs & Hill Drawing 2323-S-0903 5.
Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for CPSES Nos. I and 2", Revision 4 6.
Ebasco Calculation, " Comanche Peak SES Cable Tray Hanger Volume I", Book 2 " Computer Related Information",
Revision 3 7.
Ebasco Calculation " Comanche Peak SES Cable Tray Hanger Volume I", Book 7 " Cable Tray Hanger Load Application Location Study", Revision 1 8.
Ebasco Procedures SAG.CP4, " Seismic Design Criteria for-Cable Tray Hangers for CPSES Unit 1", Revision 3 and SAG.CP3, " Seismic Design Criteria for Cable Tray Hangers for CPSES Unit 2", Revision 6 9.
Impe11 Instruction PI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 10.
Inge11 Calculation M-12. " Qualification Procedures for Cable Tray Support Evaluations", Revision 2 TU Electric Comanche Peak Steam Electric Station L
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11.
Igell Instruction PI-11. " Cable Tray System Analysis and Qualification Closeout". Revision 1 12.
Impell Instruction PI-03, " Qualification of Cable Tray Supports", Revision 4 13.
Ebasco Procedure SAG.CP11. " System Analysis for Cable Tray and Hanger Assenbly for CPSES Units 1 & 2",
Revision 2 l
- 14. Transcripts of the Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna. Ebasco and Igell held at the CPSES site on January 26 and 27,1987
- 15. Consnunication Report between R. Ramsey, et al (!qell);
S. i;mrrison (TU Electric); R. Alexandru, et al (Ebasco);
and J. Russ, et al (Cygna), dated F&ruary 2,1987.
16.
NCIG-01, " Visual Weld Acceptance Criteria", Revision 2 i
Sunnery:
In the design of cable tray support flexural menbers (i.e.,
beams and hangers, now generally referred to as tiers and posts, respectively), Gibbs & Hill did not consider several imortant items as discussed below.
A.
Major Axis Bending Due to Transverse Loading i
Additional major axis bending stresses due to transverse loads are introduced by the vertical eccentricity between the cable tray centerlines and the beam neutral axis.
(Reference 1.) Gibbs & Hill provided calculations (Reference 2) indicating that the increase in bending stress did not exceed 2.5% of the allowable stress level.
However, the analysis incorrectly assumed that the beam was a fixed-fixed menber, effectively j
isolating it from the remainder of the support l
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structure.
In addition, the load transfer mechanism that was assumed to be provided by the tray clamps may not be applicable to all clamp configurations.
B.
Minor Axis Bending Due to Transverse Loading Minor axis bending of the beams due to transverse loading is introduced by the horizontal eccentricity between the beam neutral axis and the location of the tray clamp bolt holes in the beam's top flange.
(Reference 1.) Gibbs & Hill's response (Reference 2) did not consider the allowed tolerance in bolt hole gage per DCA 17838, Revision 8.
A load transfer mechanism was assumed to be provided by the clamp, allowing the trays and supports to act as a system. This assumption results in increased transverse loads on adjacent supports and no minor axis flexure in the beams.
C.
Torsion Due to Vertical Loading Vertical loading introduces torsion into the beams due to the horizontal offset between the tray clang location and the shear center of the beam.
In Gibbs & Hill's response (Reference 2), the torsional moment was completely eliminated, based on an assumed moment resistance provided by the tray clamps and the tray / support system concept.
(See Issue No.10 for the acceptability of the system concept.)
D.
Torsion Due to Longitudinal Loading Torsion is ir;troduced into the beam by longitudinal loading due to:
1.
The vertical offset between the tray centerline and j
the beam shear center (for longitudinal trapeze type j
supports, e.g., L-A, L-B ).
1 g
l i
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The vertical offset between the tray centerline and the shear center of the composite beam (for longitudinal supports similar to SP-7 with brace, Detail 8, drawing 2323-5-0903,etc.).
Gibbs & Hill's evaluation of the torsional effects are included in Reference 2.
The evaluation of torsion due to loading type 1 only considers the eccentricity between the shear center and the top of the tray rungs for ladder type trays or the tray bottom for trough type trays. The centroid of the tray fill is a more appropriate location from which to calculate the eccentricity. For loading type 2 the longitudinal load is applied at the bottom of the tray side rails, rather than the centroid of the tray fill. The tray clamps are assumed to provide rotational restraint to the top flange of the composite beam, and all torsional moments are assumed to be resisted by a couple formed between adjacent vertical supports through flexure of the cable tray. All these assumptions must be justified per Issue Nos.10 and 18.
E.
Reduction in Section Properties Due to Bolt Holes and Weld Undercut f
Gibbs & Hill has not consistently considered the reduction in the beam section properties due to bolt l
holes through the flanges (see Issue 2. 9) and weld undercut effects.
Based on CMC 58338, Revision ~ 0, the welded connection between the beam and hanger can l
include vertical fillet welds crossing the ws of the beam, thus weld undercut would affect the beam capacity at this critical location.
Weld undercut could also affect the beam capacity at beam-to base angle / plate connection for the cantilever type of supports. '
l In addition, based on the tray installation tolerances provided in Gibbs & Hill Specification 2323-ES-100, l
Section 2.28, and the effect of CMC 2646, Revision 5, TU Electric Comanche Peak Steam Electric Station i
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the tray clag can be located such that the bolt hole is in the same cross-sectional plane as the effect of weld undercut. Thus, it is possible that both reductions may occur simultaneously.
F.
Evaluation of Shear Stresses Gibbs & Hill has not evaluated the effects of shear stresses on beam acceptability. Shear stresses will be introduced by two loadings:
1.
Direct shear stresses due to the applied forces 2.
St. Venant shear stresses associated with torsional loads.
(See Items C and D d>ove.)
Cygna's review indicates that direct shear stresses are minor and generally do not govern the design of flexural menb ers. When these stresses are considered in conbination with the potentially large St. Venant shear stresses, the effect can be a significant factor in the menber design.
(Reference 3.)
G.
Urt> raced Length for Lateral Torsional Buckling Gibbs & Hill generally assumes an allowable major axis bending stress of 22 psi for menber designs.
The capacity reduction based on the unsupported length of the beam's compression flange (AISC Equation 1.5-7) is either not considered at all or not properly considered.
(See Issue No.14.) Justification is provided, based on the assugtion that the tray and tray clamp will provide lateral bracing to the beam's compression flange.
This assugtion is dependent on the tray clamp's ability to provide bracing (see Issue No.18) and neglects compression of the bottom flange due to support frame sidesway and seismic uplift. For cantilever type supports, the "1" value in Equation 1.5-7 is improperly selected as discussed in Issue No.14.B.
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A.
The effect of the ' vertical eccentricity is considered in the analysis of the cable tray supports. For equivalent ctatic analyses Ebasco, per Reference 5. Attachments B1 and B2, applies a major axis bending moment to the support which is equal to the applied transverse load times the distance from the beam center of gravity to the bottom of the tray. This approach is based on Study No. 7b.
(Reference 6.)
In Reference 15, Ebasco indicated that the load was assumed to act at the tray bottom rather than at the tray center of gravity. Cygna did not agree with this sad requested additional justification.
For system models, Impell, per Reference 9 Section 3.?.4, and Ebasco, per Reference 13, include an eccentricity equal to the distance from the tray center of gravity to the beam center of gravity.
B.
The minor axic bending mment due to this eccentricity is considered explicitly by Ebasco in Attachments B1 and B2 of Reference 5 in individual support models used for equivalent static analyses. The eccentricity used is equal to the distance between the beam center of gravity and the clamp bolt location. For system models, Ebasco, per Reference 13, includes a horizontal eccentricity (equal to the distance between the beam shear center and the web centerline) to account for torsion due to l
applied vertical loads.
(See Issue No. 24.C.) The magnitude of the eccentricity is approximately equal to l
or greater than the distance between the clamp bolt hole centerline and the minor neutral axis.
(Reference 15.)
j Impell, in Reference 10, indicates that the effect of thioeccentricity is not significant and will not be considered.
In this study, a moment equal to the horizontal transverse load multiplied by the eccentricity is applied to a finite element model of a single tier and one tray. The model distributes the j
i i
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Review Issues List load between the tier and the tray and shows that the majority of the load is resisted by the cable tray.
This study assumes that the clamps are able to transmit this moment in the form of a torque about the longitudinal axis of the bolt used to attach the tray -
clamp to the beam. This assumption is not justified.
C.
For equivalent static analyses, Reference 5, Attachments B1 and B2, and for system models, Reference 13 Ebasco considers an eccentricity equal to the distance from the shear center to the centerline of the beam web.
This is based on a study in Reference 7 which indicates that the ver+1 cal load from the tray is transferred at the location of the web centerline.
This is reasonable for downwards loading from the tray, but may be unconservative for upwards loading, which would i
be applied at the clang bolt locatio1.
In Reference 14 Ebasco deferred any further discussion.
l Impell, per Reference 9. Section 3.2.4, includes an eccentricity equal to the distance between the beam's shear center and center of gravity.
This is included in the model by providing a spring (to model clamp stiffness) capable of resisting only vertical tray loads at the end of a rigid link with a length equal to the eccentricity. However, Impell models a rotational spring coupling torsion in the beam to minor axis bending of the cable tray.
This may result in a large portion of the torsional load being absorbed by the t
cable tray.
D.
For system models, Ebasco in Reference 44, and Impell in Reference 9. Section 3.2.4, model an eccentricity equal to the distance between the center of gravities of the cable tray and the beam.
For equivalent static models, Ebasco, in Reference 5, Attachments B1 and B2, considers an eccentricity that depends on the nunber of bolts between the cable tray TU Electric Comanche Peak Steam Electric Station L
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05/08/87 Revision 13 Page 147 CABLE 1 RAY SUPPGtT5 Review Issues List and the clag. For clamps with a single bolt, the eccentricity used-is the distance between the centerline of the tray clag bolt and the neutral axis of the b eam. For clamps with two or more bolts, the distance from the center of gravity to the top flange of the beam-is used as the eccentricity.
In Reference 14, Ibasco indicated that this is done based on the assumption that a portion of the torsion will be resisted as' minor axis bending of the cable tray since the two bolts will develop a couple. The cable trays are not evaluated for the effect of this moment.
E.
The evaluation of the effect of bolt holes through the channel flange is addressed in Issue No. 9.
Since the supports will be individually evaluated based i
on the as-built support configuration, weld undercut does not have to be considered on.a generic basis. The project is performing weld inspections in accordance with Reference 16.
If the welds satisfy the undercut limitations given in Reference 16, undercut will not be considered in the analyses.
If the undercut exceeds the allowable, the inspection report for the support is marked unsatisfactory and "dispositioned".
F.
The evaluation of cable tray support menbers includes the effect of direct shear and St. Venant shear stresses. This is specified in Section VI and Attachment M of Reference 5 and Attachments 4 and 5 of Reference 12.
In addition to the shear stresses associated with torsional loads, the warping normal stresses due to torsion are included in the menber evaluations, Impell and Ebasco consider the entire cross-section of l
cogosite T-channels to be effective in resisting torsional moments. Cygna is concerned that this assumption is not correct as the boundary connections of TU Electric Comanche Peak Steam Electric Station L
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G.
See Response for Issue No.14.B.
Status:
A.
Open: Ebasco to provide justification for eccentricity used in ESM models. Closed for Igell and Ebasco for system models.
B.
Open: Additional review of Impell calculations (Reference 10) is required.
C.
Open: Additional review and discussion of the modelling required.
D.
Open: Further review of the eccentricities considered in Ebasco's models is required. Closed for system models.
E.
See Issue Ib. 9 for the status of the evaluation of bolt holes in menbers. Cygna must review Reference 16 regarding the effects of weld undercut and obtain additional information on the disposition methods.
F.
Open pending review of Impell and Ebasco responses on torsional capacity of comoosite sections.
G.
See status for Issue No.14.B.
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- 25. Cable Tray Qualification
References:
1.
Gibbs 4' Hill Specification 2323-ES-19, Revision 1 2.
Gibbs & Hill Calculation Binder 2323-SCS-111C, Set 7 Revision 1 3.
T.J.- Cope Test Report and Calculations for the Qualification of Cable Trays 4.
CPSES FSAR, Section 3.108.3, Amendment 44 5.
Gibbs & Hill Specification 2323-ES-100, Revision 2 6.
IEEE "Reconnended Practices for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations," STD 344-1975 7.
CPSES FSAR Section 3.78.3.5 8.
Gibbs & Hill Drawing 2323-S-0901, Revision 4 9.
L.M. Popplewell (TUGCO) letter to N.H. Williams (Cygna),
" Response to Cygna Review Question 2.1 of Letter 84056.019," dated August 27, 1984 with attached calculations 10 Cable Tray Thermo-Lag Evaluation Safeguards Building, Elevation 790'-6," Cygna Technical File 84056.11.1.1.315 11.
TUGC0 Instruction CP-EI-4.0-49 Revision 1 12.
N.H. Williams (Cygna) letter to W.G. Counsil (TUGCO),
" Cable Tray / Conduit Support Review Questions,"
84056.089, dated October 21, 1985 13.
Ebasco Calculation, " Comanche Peak SES Cable Tray Hanger Volume 1", Scok 1 " General Input Data", Revision 3 TU Electric 1
Comanche Peak Steam Electric Station L
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05/08/87 Revision 13 Page 150 CABLE 1 RAY SUPPGtTS Review Issues List 14 Ige 11 Instruction PI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 15.
Impe11 Instruction PI-06, " Tray and Clip Qualification",
Revision 0
- 16. CCL Test Plan:
" Static Tests of Cable Trays and Fittings", Procedure No. 1903.20-1, Revision 1
- 17. Ebasco Instruction, " General Instructions for Cable Tray Hanger Analysis for CPSES, Nos.1 and 2", Revision 4
- 18. Transcripts of the Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna. Ebasco and Impell held at the CPSES site on January 26 and 27,1987 19.
Impe11 Calculation M-03, " Cable Tray Properties",
Revision 4 Summary:
The qualification requirements for cable trays are outlined in References 1 and 4 In reviewing related specifications, calculations, and installations of cable trays, Cygna has noted several areas of concern.
A.
Dynamic Amplification Factor Qualification of cable trays is performed through static load testing and calculation of loading interactions for dead load plus three cogonents of seismic load.
(Reference 1. Section 3.9 and Reference 3.) Seismic loads are calculated by the equivalent static load method, using total tray dead weight times the peak spectral acceleration.
No, apparent dynamic amplification factor (DAF) is used. Reference 6, Section 5.3, and Reference 7. recommend the use of a DAF = 1.5 unless justification is provided. (See Issue No. 8. )
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Cable Tray Stress Interaction The interaction equation specified for checking cable tray capacity (Reference 1. Section 3.9.4) is limited in its application and may have been used incorrectly.-
The testing and qualification of cable trays is based on an 8'-0" simply supported tray span (References 1 and 3); yet Reference 8 Note 13, allows a support installation tolerance resulting in a maximum tray span i
of 9'-0" for Unit 1.
The capacity values derived in the tray testing are i
total loads (Ibs) uniformly distributed over an 8'-0" l
section of cable tray.
(Reference 3.) These values, F, F and F<, as used with the interaction equation, n
t are only app 1' cable to tray sections with 8'-0" spans.
However, for the fire protection evaluation calculations (Reference 2) and tray span violation calculations (Reference 9), total loads for various tray spans were calculated as ff = w
- 1, where w is the tray unit weight and 1 is the tray span. This load was compared with the rated tray capacity using the interaction l
equation.
For evaluation of trays with spans other than 8'-0",
a capacity comparison must be made in terms of tray 2
bending soment which is proportional to (w
- 1 ), rather than the total load on the tray section. For example, if an 8'-0" tray span will support a total distributed load of 1600 lbs (200 lb/ft), by increasing the span to 10'-0", a uniform load of 128 lb/ft (1280 lbs) would result in the same bending moment at aid span.
Therefore, the capacity for the 10'-0" span would be 1280 lbs and not the 1600 lbs assumed.
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Modifications to Cable Tray Hardware and Siderail Extensions Cygna has noted several instances of modifications to cable tray hardware without adequate justification or documentation.
I 1.
Tray Segment No. T130SCA46 is assumed to be a 24"x6" ladder-type tray in the fire protection evaluation calculations for Safeguards Building Elevation 790'-6".
(Reference 10.) Cygna's walkdown indicates that this tray is actually a 24"x4" ladder-type tray with 6" side rail extensions added to increase the tray depth. The tray qualification test report (Reference 3) does not provide qualification for trays using side rail extensions. The procedure governing fire protection evaluations (Reference 11 Section 3.2.2.2) states:
Evaluation process described in 3.2.2 is not applicable to the cable trays (and their supports) where additional sidera11s are added. For such cases, actual as-built configuration of the tray system with actual cable weight shall be taken into account and proper engineering evaluation performed.
No standard methodology is recomended, but shall be based on acceptable l
engineering practice.
The referenced calculations do not perform an evaluation of this tray segment. These calculations (Reference 10) were obtained from TUGC0 prior to their design review; therefore, this possible omission may be corrected through the design review process.
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2.
Tray Sepent T1205BC35 is joined to a tray reducer with side rail splice connector plates.
These
. plates have been modified by removing portions of their bottom flanges such that only the web area remains. This connector will not satisfy the requirements of Reference 1, Section 3.7, Paragraph f, which states that connectors "shall
{
have moment and shear strengths at least equal to those of the continuous uncut side rail." Cygna was unable to locate documentation justifying this modification of vendor-supplied hardware.
D.
Cable Tray Section Properties Cable tray section properties are calculated using the static test results.
(Reference 3.) The moment of inertia is calculated based on the flexural displacement formula for a simply supported beam. For horizontal transverse loading (i.e., in the plane of the rungs) ladder-type cable trays show a truss-like behavior, and the deflection will be due to both flexure and shear deformatisns.
This will affect the calculated moment of inertia as used in any Gibbs & Hill analyses which consider the tray properties for frequency or displacement calculations.
Response
A.
Ebasco performs cable tray qualification in accordance with Reference 13. A multi-mode response multiplier (MtM) of 1.25 is used for the static and equivalent static qualifications.
f Impell performs response spectrum analyses of the cable tray systems in accordance with Reference 14 The forces and moments in the cable tray are calculated as I
part of this analysis.
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Cable trays are evaluated based on the individual as-built span lengths.
In Reference 13. Ebasco has developed tables of allowable tray spans for specific buildings and elevations. These tables provide a maximum tray span of 8'-0", which is consistent with the original tray testing program. For tray spans greater than 8'-0",
the trays are qualified by calculations.
Impe11 follows a similar approach in tray evaluation in Reference 15.
A series of tray capacity tests and tests of fittings have been performed by CCL.
(Reference 16.) Cygna will audit the test results when available.
C.
For the design verification, Ebasco, in Attachment C of Reference 17, includes the weight of siderail extensions in calculating the dead weight of the tray but does not i
consider their contribution to tray stiffness.
Impe11 does not consider the mass or stiffness contributions of the siderail extensions. See Issue 2. 21.D.
In Reference 18,' it was indicated that the Project has identified modified splice plates as a potential problem. TU Electric has issued a Significant Deficiency Analysis Report (SDAR 86-52) to address this prob lem.
D.
Cable tray section properties are calculated based on test data (References 13 and 19) assuming load-deflection behavior predominated by flexure.
The results of the recent tray tests (Reference 16) will be used to confirm that this assumption is appropriate for the T.J. Cope trays used in CPSES Unit 1.
Status:
A.
Open: Cygna review of Reference 13 required for acceptance of Ebasco's approach. Closed for Impell.
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B.
Open: Cygna review of the results of the tray testing program (Reference 16) and the use of the test data in cable tray evaluations-is required.
C.
See Issue No.~ 21.0 for the status with respect to I
s sidera11 extensions. Open for nodified splice plates pending the completion of the evaluation of SDAR 86-52.
'y i
D.
Open: Cygna will review the results of the cable tray tests when available.
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- 26. - Base AngIe Design is3
(.
s 3
p f
References:
1.
Gibbg p Hill,Cdicuhtion Binder 2323-SCS-215C, Sets 2 c
through 6 2.
Gibbs & Hill Calculation Binder 2323-SCS-1010, Set 1 j
3.
Transcripts of the Cable Tray Design Verification
,s Meeting between TU Electric, Cygna. Ebssco and Impell held at the CPSES site on January 26 and.27,1987.
- 4. _ Ebasco Instructions, "4neral Instructions for Cable
( p ray Hanger Analysis for CPSES Nos. I and 2", Revision 4 T
.i 4
- 5. 7 Igell Instruction PI-07, " Design Verification of Base Plates, Base Angles and Esedded Plates", Revision 3
{
'< l 4,
l o
'3 Summary:
A.
Base Angles Modelled as Simply Supported Beams In References 1 and 2, the. base angles were modelled as simply supported beams., This modelling technique does y,,]
not inc1'ide the stiffening effects of concrete bearing s
at the a731e ends.
N l
B.
Principal Axes 1
\\
1 f
2 ;,E f ;
The principal axes were not considered in the analyses -
/F of the base angles'stt>jected to the various loadings.
e Jf.
C.
Maximum Base Angle Lengths %t Considered The base angle lengths due to the maximum spacing of the Richmond Inserts were not considered in the Working
/
Point Deviation Study'.
H.
D.
Lack of Design Calculations for Case Angles For support types D, D ' l'A ' l-A, SP-4, SP-6, SP-8, 3
2 l
4 f
and Detail 11 (Draw'ng 2323-5-0905) the design ici j"
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calculations do not include an evaluation of the base angles.
' Response:
A.
Base angle behavior has been studied in great detail in a number of finite element models by Ebasco and Impell. The stiffening effect of the concrete was included in these models. From these models a set of boundary stiffnesses were developed for use in the support models.
The development of these values are discussed under Issue-No. 3.
Per Reference 3, no action is required for the j
evaluation of. stresses in the base angles. By ignoring the stiffening effect of the bearing on the concrete, the calculated stress level should be conservative.
B.
Ebasco has indicated that the principal axes section properties will be used in the calculation of bending stresses for the base angles. This is documented in Attachment E of Reference 4 Attachment F of Reference 5 indicates that Impell utilizes geometric properties for base angles.
C.
This is no longer an issue.
Per Reference 3, the design verification of cable tray supports will use the as4uilt lengths of base angles and spacing between anchor bolts.
D.
This is no longer an issue.
Per Reference 3, the design verification of base angles is done individually for each support.
Status:
A.
See Status for Issue No. 3. A.
B.
See Status for Issue No. 25. A.
C.
Closed.-
D.
Closed.
TU Electric 1
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- 27. Support Qualification by Similarity
References:
1.
Gibbs &~ Hill Calculation Binder 2323-SCS-104C, Set 1 2.
Gibbs & Hill Calculation Binder 2323-SCS-104C, Set 5 3.
R.E. 8111ard (Gibbs & Hill) letter to J.B. George (TUGCO), GTN-69361, dated August 21, 1984, with attachments 4
R.E. Ballard (Gibbs & Hill) letter to J.B. George (TUGCO), GTN-69377, dated August 29, 1984, with attachments.
5.
Transcripts of the Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna. Ebasco and Impell held at the CPSES site on January 26 and 27,1987.
6.
Ebasco Calculation, " Comanche Peak SES Cable Tray Hanger Volume I", Books 4 & 8, " Cable Tray Hanger Geometry Grouping", Revision 1 i
7.
Communications Report between B. Lashkari (JBA); J.' Park
[
(Impell); J. Christoudias, D. Fong, P. Harrison, R.
Alexandru, S. Chen, F. Hettinger, J. Swanson (Ebasco);
W. Horstman, D. Leong, J. Russ, S. Tuminelli (Cygna),
dated February 10, 1987, 8:30 a.m.- 5:00 p.m.
Suimmary:
A.
Qualification by Similarity in Original Design Calculations In the Gibbs & Hill design calculations, several support types were qualified by similarity to another support type without showing similarity. Cygna's review of the geometry, loading, connection details, etc. indicated that the designtwere not abviously similar, and that calculations should have been provided. Supports in this catepry are:
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Detail A, Drawing 2323-El-0700-01-S.
Reference 2 states that Detail A is similar to Case SP-7.
Cygna noted that the cantilever length for Detail A is greater than-for SP-7 and that the anchor bolt attachment is unlike the attachment for SP-7.
t
- 2.. Detall N, Drawing 2323-El-0601-01-S.
)
Reference 1 states that Detail N is similar to Details V and R on the same drawing. Cygna noted that the frame geometry and tray locations for Detail N was unlike either of the cited details.
3.
Detail J. Drawing 2323-El-0601-01-S.
Reference 1 states that Detail J is similar to case B.
Cygna noted that the menber sizes used are 3
different than those for Case B, and the frame 3
dimensions exceed the design limits for Case B +
3 4.
Detail V, Drawing 2323-El-0601-01-S.
Reference 1 states that Detail V is similar to i
Detail B, drawing 2323-El-0713-01-S. Cygna noted that Detail B is a three bay frame with braces in all bays and was designed as a pinned truss.
Detail i
V does not have braces in all bays, and if the same design technique is applied, the frame would be statically unstable.
B.
Qualification by Similarity in the Working Point Deviation Study Allowed working point deviations for individually designed supports were established based on similarity to standard support types without justification. See Issue No.12.H for a discussion of this topic.
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Response
A.
Impe11 does not use similarity in the support design verification. Each support is evaluated individually based on the as built configuration.
Per Reference 5, Ibasco does not use similarity in the same manner previously used by Gibbs & Hill. However, l
they do perform " grouping" of supports as defined in Reference 6.
The grouping technique was discussed in References 5 and 7.
Supports are grouped based on geometry, dimensions and tray loading. One enveloping support in the group is analyzed in order to qualify the structural menbers of all supports in the group.
Other components of the supports (e.g., anchor bolts, base angles, welds, etc.) are evaluated individually for each support within the group.
B.
See Response for Issue No. 27.A.
Status:
A.
Open: Cygna has completed the audit of Ebasco's support grouping procedures and has raised several questions regarding the content of the data base used to develop the support groups.
B.
See Status for Issue NO. 27. A.
l l
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CABLE 1 RAY SUPPGt15 Review Issues List
- 28. Critical Support Configurations and Loadings
~
References:
1.
Gibbs & Hill Calculation Binder 2323-SCS-101C, Set 1 2.
Gibbs & Hill Calculation Binder 2323-DMI-5P 3.
Gibbs & Hill Calculation Binder 2323-SCS-215C, Sets 2-5 f
. 4.
Gibbs & Hill Specification 2323-ES-19. " Cable Trays,"
Revision 1 5.
N.H. Williams (Cygna) letter to W.G. Counsil (TUGCO)
" Cable Tray / Conduit Support Review Questions,"
84056.089,: dated October 28, 1985 6.
Transcripts of the Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna, Ebasco and Impe11 held at the CPSES site on January 26 and 27,1987 Summary:
A.. Critical Aspect Ratios Gibbs &. Hill design calculations (References 1, 2 and 3) for trapeze type supports considered only a limited nunber of support aspect ratios.
Justification was not provided to show that the chosen aspect ratios would provide the critical configuration to evaluate all components of the support design. The determination of aspect ratios was based on an assumed frame width based on supported tray width and the maximum frame height.
The frame width determination assumed that: (a) trays i
were installed with a minimum 6" horizontal spacing, (b) the distance between the side rail of a tray and the vertical hanger flange was a minimum of 3", and (c) all trays on a support were 30" or less in width.
Cygna's support walkdown noted that trays were installed with spacings as small as 1" between adjacent trays, and i
0" between tray siderails and the hanger flange.
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Reference 4 indicates that cable tray installations at -
CPSES allow a maximum tray width of 36".
B.
Tray Location'on Support In the design of the frame menbers for trapeze supports, Gibbs & Hill. typically applied the loadings to the frame in a symmetric pattern.
In reviewing the support layout plans, Cygna has noted that the cable trays are often located in an asymmetric fashion on the supports. This could result in higher stresses in the support menbers and higher loads on the anchorages than considered in 1
I the design.
Response
A.
The choice of critical aspect ratios for the design of generic support types is no longer an issue since all cable tray supports are design verified based on their as-built configuration. This was discussed in Reference 6 as it relates to the support grouping used by Ebasco for certain groups of similar supports. See 1 --
Issue No. 27 for additional details.
B.
Per Reference 6, the design verification of cable tray supports is based on the as4uilt support configurations. Therefore, this is no longer an issue.
Status:
A.
Closed.
l B.
Closed.
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- 29. Cumulative Effect of Review Issues
References:
1.
TU Electric CPSES, " Generic Issues Report (GIR):
Evaluation and Resolution of Generic Technical Issues for Cable Tray Hangers", Revision 1 Summary:
In this Review Issues List, a nunber of the cited issues may lead to small unconservatisms when occurring singly in a support design. Such unconservatisms may usually be neglected.
However, since several of these issues pertain to all cable tray support designs on a generic basis, their t
effect can be cumulative, such that the sum of many small unconservatisms may be significant. Therefore, any reevaluation of support designs should consider the cumulative effect of all pertinent Review Issues.
Response
TU Electric provided the following response in Reference 1:
This issue is inherently addressed by the comprehensive engineering approach to the design verification of the Electrical Cable Tray Raceways and by the imple:nentation of extensive "as4uilt" analysis qualification, and test acti vities.
As discussed in the introduction (of Reference 1), all 4
l the generic technical cable tray issues fall into four categories: deviations between the "as-designed" and "as built" raceway syc.tems, control of design docuw=nts, analysis assumptions and methods, and design assumptions and methods.
The "as-built" vs "as-designed" issues are addressed L
cumulatively via the comprehensive "as4uilt" program.
I 100 percent of all accessible cable tray system components have been "as4uilt".
Inaccessible components critical to the design verification effort have or will be rendered accessible or have been classified as " hidden attributes".
Hidden attributes L
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In addition, this program has resolved
. instances of improper installation and poor construction quality.
4 The issues related to control of design documents have been cumulatively addressed by virtue of the design verification program which will generate "as built" design documentation, support drawings, and qualification calculations-on 100 percent of the cable tray supports.
All analytical issues (analysis assumptions and methods) and design isst:es (design criteria and assumptions) have L
beer simultaneously addressed by tha development of procedures and instructions, supported by studies, which have systematically considered each issue. By virtue of the overall approach which has been implemented, the cumulative effect of these issues have been addressed directly.
i.
Additionally, an extensive test program which has included component tests and full scale system dynamic tests has provided additional data to validate the overall design verification approach as well as demonstrate the stbstantial conservatism in the methods. Thus the actual margins of st.fety of the ceble tray systems have been demonstrated to be much larger than the margins calculated in design verification.
In summary, the overall design verification approach has fully addressed and resolved each of the generic 4
technical issues both individually and collectively, provided 100% "as built" documentation of the cable tray system designs including resolution of improper installation or construction, and.onfirmed the
{
conservatise of the approach through extensive i
f TU Electric
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Status:
This issue will remain open until such a time as all other issues have been satisfactorily resolved. Cygna will perform a review of the approach used to assess " hidden attributes" and audit the results of the various test pro grams. Cygna will review the ANCO systens tests as a basis for assessing the cumulative effects of any potentially unconservative analytical assumptions. At this time, Cygna is still evaluating the applied)ility of the systens tests to certain med)er behavioral questions.
Specifically, issues associated with non-ductile failure modes -(Issue No.1), allowd)1e flexural stresses for angle sections (Issue 7.8), and the unsupported lengths for sections susceptible to lateral torsional buckling (Issue 14.8) are still open and require further discussion as to code interpretations.
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- 30. Cable Tray Damping Values
References:
1.
CASE /MtC Hearing Transcripts, 13196, 13303-13307, 13318, 13321, and 13454-13461 l
2.
USAEC, " Damping Valves for Seismic Design of Nuclear Power Plants" Regulatory Guide 1.61, October 1973 3.
Ebasco Procedure SAG.CP.05, " Dynamic Cable Tray System Test Specification", Revision 3 4.
ANCO Testing Laboratories, " Test Plan - Dynamic Testing of Typical Cable Tray Support Configurations". D3cument No. A-00150, Revision 1 5.
Ispell Report 09-0210-0017. "CPSES Cable Tray System Analysis / Test Correlation", Revision 0 Summary:
Damping values of 4% and 7% have been used for the evaluation of OBE and SSE seismic inertia loads, respectively, in the design verification of the CPSES cable tray systems. These damping values correspond to those recommended by Reference 2 for bolted steel structures.
CASE, in Reference 1, has questioned the acceptability of these values for the cable tray systems.
Response
Cable tray system dynamic testing has been performed in accordance with References 3 and 4 The results of these tests, as discussed in Reference 5, validate the selected damping values.
Status:
Open: Cygna to review Reference 5 and the supporting test I
data.
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Review Issues List
- 31. Modelling of Boundary Conditions
References:
1.
CASE /MtC Hearing Transcripts 13707 and 13776 2.
ANC0 Testing Laboratory, " Test Plan - Dynamic Testing of Typical Cable Tray Support Configurations" Document No.
A-000150, Revision 1 3.
Inge11 Report 09-0210-0017, "CPSES Cable Tray System Analysis / Test Correlations", Revision 0 4
Impe11 Special Study No. 5.9, " Oversized Bolt Holes",
Preliminary Issue 5.
Gibbs & Hill Drawing 2323-S-0903, Revision 3 Summary:
Gibbs & Hill's cable tray support designs for CPSES employ Hilti Kwik bolts and Richmond Inserts for' anchorage to the concrete structures. The design drawings (Reference 5) specify that the holes in the base plates or base angles are to be 1/8 inch larger in diameter than the nominal diameter of the anchor bolt.
During testimony, Reference 1. CASE has questioned the behavior of those bolted connections due to the hole size and the modelling techniques used to represent the associated boundary conditions.
Response
See Response for Issue No.14.F.
Status:
See Status for Issue No.14.F.
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Review Issues List
- 32. Conduits Attached to Cable Trays or Supports
References:
1.
Transcripts of the Cable Tray Hanger Design Verification.
Meeting between TU Electric, Cygna. Ebasco and Impell held at the CPSES site on January 26 and 27,1987.
2.
Ebasco Instruction, " General Instructions for Cable Tray
. Hanger Analysis for CPSES Nos. I and 2", Revision 4 3.
Igell Instruction PI-02, " Dynamic Analysis of Cable Tray Systems", Revision 5 Summary:
In several instances within Cygna's cable tray support review scope, conduits were attached to a cable tray support or directly to the cable tray (e.g., conduit support type.
CSD-16).
A.
How were the loads from the attached conduit being considered in the cable tray support design verifications?
B.
How were the loads from a conduit attached to a cable tray considered in the cable tray design verifications?
C.
Attachment U of Reference 2 indicates that cable tray supports with conduits attached must be checked to determine the support fundamental frequency at the conduit attachment location. The frequency is calculated by performing a kinematic condensation of the support model to the degree of freedom associated with the conduit attachment location. Cygna is concerned with the accuracy of a frequency analysis based on the condensation of the entire mass and stiffness matrices to a single degree of freedom.
Response
A.
The luged weight of the attached conduits were calculated based on the tributary conduit span on either I
WA TU Electric Comanche Peak Steam Electric Station L
Independent Assessment Program - All Phases o -
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05/08/87 Revision -13 Page 169 CABLE MAY SUPPRT5 Review Issues List side of the cable tray support. Conduits clags were assumed to transmit three directional loads to the cable l
tray supports.
t For cable tray supports analyzed via the equivalent static method, Ebasco considered attachment of conduits in accordance with Attachment U of Reference 2.
The loads from the conduit were calculated using the peak acceleration from the appropriate amplified response spectra (2% damping OBE, 3% damping SSE) and a dynamic amplification factor of 1.5.
For the system models analyzed by the response spectrum method, Impell, in Reference 3, included the conduit lumped weights as a part of the model. Seismic loads j
were developed as part of the response spectrum
~
analysis, using 4% damping OBE and 7% damping SSE amplified response spectra. This approach assumed that the conduit had the same damping as the cable trays rather than the lower damping values used by Ebasco and that the conduits were rigid (i.e. by modelling these as lumped weights the dynamic effects associated with the flexibility of the conduit spans was neglected).
B.
Ebasco, in Reference 1, requested that the response to i
this question be deferred.
C.
Ebasco will prepare an evaluation of the condensation j
method used in determining support frequency at the i
conduit attachment location.
i Status:
A.
Open: Justification for the modelling of conduits as lumped weights in the system sodels is required.
8.
Open.
C.
Open.
i TV Electric l
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- 33. As4uilt-Walkdown Procedures
References:
- 1. ' TU Electric Procedures TNE-FVM-CS-001, " Field i ~
Verification Method Unit 1 Cable Tray Hanger As-Builting and Design Adequacy Verification Program", Rev. 5. July i
1,1986, and TIE-FVM-CS-003 " Field Verification Method 1
Unit 2 Cable Tray Hanger As-Builting and Design Adequacy j -
Verification Program", Revision 1, October 18,19P6, Supplemental Procedure for Unit 2 Walkdown TNE-FVM-CS-019. " Selected Cable Tray Attributes Data Collection -
j Unit 2", Revision 1, Septenber 3,1986 2.
Transcripts of Cable Tray Hanger Design Verification Meeting between TU Electric, Cygna. Ebasco and Impell held at the CPSES site on January 26 and 27,1987 3.
NCIG-01, " Visual Weld Acceptance Criteria", Revision 2 4.
TUGC0 Instruction QI-QP-11.10-9, " Modification, Rework and "As4uilt-Inspection / Verification of Cable Tray Hangers in Unit I", Revision 6 Summary:
As a part of the cable tray hanger design verification program as4uilt drawings are being developed for all cable tray supports. These as4uilt drawings will be based on engineering walkdowns performed in accordance with Reference 1.
Based on a review of the procedure Cygna raised several questions during the meeting documented in Reference 2.
A.
As-built Tolerances for Dimensional Measurements i
Table 5 of Reference 1 provides a nunber of measurement i
tulerances for menber lengths, anchor bolt spacing, etc.
1.
What is the basis of the given tolerances?
i 2.
Fow are these tolerances considered in the support evaluations?
1 TU Electric Comanche Peak Steam Electric Station
. lililllilillibilll$1ll Independent Assessment Program - All Phases Job No. 84056 PRJ:RIL4
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05/08/87 Revision 13 Page 171 CABLE RAY SUPPGtTS Review Issues List B.
Cable Tray Support Walkdown Procedures /Insructions.
With respect to the walkdown/ inspection procedures and the production of as4uilt drawings, Cygna has the following concerns:
1.
What is the basis for the acceptance of WAC as the weld inspection criteria? How have these criteria been reconciled with the analysis assumptions?
2.
Where are the dimensions for the locations of the ends of brace menbers taken to? Are the dimensions used in calculating whether or not to consider the working point offset from the beam / hanger intersection taken directly in the walkdown?
(See Issue No.12. )
3.
In Section 3.2.29.2.a.2.b of Reference 1, what is the basis for assuming that the effective throat of full and partial penetration welds is one half of the beveled menbers thickness? How will this effective throat be used in the design verification of the support?
4 Expansion anchor types and enbedment lengths are to be as-built.
How are Hilti Super Kwik-bolts being identified if the " star" stamp is not present or obscured by paint? How is the enbedment depth determined if the length mark is obscured by paint?
S.
Section 3.2.2.B.7 of Reference 1 requires that the attachments of other items to the cable tray support must be recorded. Does the walkdown show the method of attachment (e.g., welds, bolts, etc.) of other items to the cable tray support?
Is the extent on any Thermo-lag on the att::chment. recorded?
If the attachment is a conduit, is the extent and configuration of Thermo-lag on the conduit span recorded?
TU Electric Comanche Peak Steam Electric Station yg,g Independent Assessment Program - All Phases Job No. 84056 PRJ:RIL4
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l C.
C&le Tray Span Walkdowns In Section 3.9 of Reference 1, the procedure for the walkdown of cable tray spans is provided.
1.
The use of tray covers to allow the reduction in l
minimum spacing requirements at the discretion of I
craft, implies that their existence and location is not fully documented. Section 3.9 does not address identifying and locating tray covers.
What is the basis for not considering tray covers in the I
development of the cele tray span sketches? How will any noted tray spacing violations be reconciled with other discipline requirements, e.g.,
electrical, damage study, etc.?
2.
Modified tray connection plates have been identified. Will such connections be located?
If not, why?
3.
Will tray siderail extensions be located?
If not, why?
4.
Will the locations and types of other components, e.g., conduits, light fixtures, etc., attached to the cable trays be identified and recorded?
If not, why?
Response
A.
In Reference 2 the Project indicated that they would like to defer these questions until additional documentation is available.
B.
1.
In Reference 2 TU Electric indicated that they have received MtC approval for the use of "WAC at CPSES.
According to WAC, if a weld satisfies the inspection requirements (e.g., weld length, size, undercut limits, etc.) there is no need to consider any impact on the weld or menber design.
TU Electric 1
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05/08/87 Revision 13 i
Page 173 CABLE 1 RAY SUPPGt15 Review Issues List 2.
In Reference 2. Ibasco provided a sample of several support as built drawings showing the measurement locations. The walkdown dimensions are used to
' calculate the working point offset for the modelling.
^
3.
In Reference 2, Ibasco indicated that it is not possible to visually determine the weld penetration depth. Therefore, one half of the member thickness is used for conservatism. This value is used in calculating the weld stresses. Justification of this assunption was not provided.
i 4.
In Reference 2, Ibasco indicated that Ultra-sonic Testing (UT) will be used to identify the expansion anchor type if no " star" is visible.
Enbedment can also be checked by UT.
If UT cannot be performed or is nonconclusive, the anchor bolt is treated as an inaccessible attribute.
5.
The type of attachment including its connection is identified.
Procedurally, the extent of Thermo-Lag is not required. Conduits are noted as well as their span lengths.
(Reference 2.) Additional procedures 3
are to describe load transfer requirements between disciplines.
t C.
At the time of the pslic meetings (Reference 2), the response to this issue was deferred to a later date.
In the pslic meetings held at the CPSES site on April 21, 1987, additional procedures were described to Cygna which addressed this issue.
Status:
A.
Open.
t B.
1.
Open: Cygna to review the NtC acceptance of WAC and i
the applicability of the criteria to cable tray supports at CPSES.
M, TU Electric Comanche Peak Steam Electric Station Independent Assessment Program - All Phases WNMMMNumul Job No. 84056 PRJ:RIL-b d
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05/08/87 Revision 13 I
Page 174 CABLE 1 RAY SUPPGt15 Review Issues List 2.
Closed.
3.
Open: Cygna internal discussion is required.
.]
- 4. -
Open pending review of the inaccessible attributes study.
5.
Open: Additional review is required.
C.
Open: Additional review required.
l l
l TU Electric g[,,,
Comanche Peak Steam Electric Station Independent Assessment Program - All Phases 111111111111111111111111111111 Job tb. 84056 PRJ:RIL b
V
-,c 2121 N. Califor.1:a BNd. Suite 390, Walnut Creek, CA 94596 415/934-5733 May 8,1987 84056.111 Mr. W.G. Counsil Executive Vice President TU Electric Skyway Tower 400 North Olivre Street, L.B. 81 Dallas, TX 75201
Subject:
Cable Tray Support Review Issues List (RIL)
Comanche Peak Steam Electric Station Independent Assessment Program - All Phases Job No. 84056
References:
1.
TU Electric " Generic Issues Report - Evaluation and Resolution of Generic Technical Issues for Cable Tray Hangers", Revision 1
Dear Mr. Counsil:
Enclosed is Revision 13 of the Cable Tray Support Review Issues List (RIL).
All significant changes are indicated by a revision bar in the right margin.
This revision to the RIL is based on the information provided in Reference 1, transcripts of public meetings, documents provided by TU Electric and the results of Cygna audits up through April 1,1987.
O t[
ll b4pd San Francisco Boston Chicago Parsippany
F Ilf.E
=.
Mr. W.G. Counsil 84056.111 May 8,1987 Page 2 If there are any questions, please call at yeur convenience.
Very truly you.s, N. 0, S
w N.W. Williams Project Manager NHW:jst Attachments cc:
Mr. Chris C imes (USNRC) w/ attachments
< Ms; A. Vie.tti-Cooli(USNRC) w/ attachments Mr. 3. Redding (TU Electric) w/ attachments Mrs. 3. Ellis (CASE), w/ attachments Mr. D. Pigott (Orrick, Herrington & Sutcliffe) w/ attachments Mr. L. Nace (TU Electric) w/ attachments Mr. R. Alexandru (Ebasco) w/ attachments Mr. B. Ramsey (Impell) w/ attachments Mr. E. Siskin (SWEC) w/ attachments Mr. 3. Muffett (TU Electric) w/ attachments
..