ML19207B057

Forwards Response to IE Bulletin 79-02,Pipe Support Base Plate Design Using Concrete Expansion Anchor Bolts. Testing,Verification,Design Review & Repair Program Initiated to Ensure Adequacy of Installation

ML19207B057
Person / Time
Site:	Farley
Issue date:	06/06/1979
From:	Clayton F ALABAMA POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 7908230309
Download: ML19207B057 (29)

Text

e . A abit a Power Cc"pr>

600 N >rm 18 'sw Pos'Cr ce B =P M 1 8 mry c A'lbr a 35.T Te crime 205 323 SM i n

F. L CLAYTON, JR w ,,,,,.-,

Mabanla POhU tv s >< " +> > . c. ,

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June 6,19 79 ,',

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Docke t Nos . 50-348 ca 50-364 NRC IE Bulletin No. 79-02

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Mr. James P. O'Reilly -

U. S. Nuclear Regulatory Commission Region II 101 Mariet ta S tree t, N. W.

Suite 3100 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

In response to IE Bulletin 79-02, Pipe Support Base Plate Design Using Concrete Expansion Anchor Bolts, dated March 8,1979, Alabama Power Company submits the following response for Farley Units 1 and 2.

Yours very truly,

. . lay n, Jr .

FLCJr/ KAP /mmb Enclosure cc: Mr. R. A. Thomas Mr. G. F. Trowbridge

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k 9 7908230 4

., ~ mo987 OPPCIll COPY

Docket No. 50-364 July 6,1979 NRC IE Bulletin No. 79-02 Mr. James P. O'Reilly

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Page bc: Messrs. J . T . Yo ung R. P. Mcdonald H. O. Ihrash

0. Batum Don Crowe W. G. Hairston, III K. A. Pikett Ken McCracken T. N. Epps Ron George C. Biddinger J. A. Mooney R. R. Todd J. D. Jones W. B. Shipman A. A. Vizzi

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t This report is in response to I.E. Bulletin No. 79-02 concerning pipe support base plate designs using concrete expansion anchor bolts. In response to this bulletin, Alabama Power has initiated a testing, verification, design review and repair program for concrete anchor bolts to ensure adequacy of installation. The specific responses to the bulletin are provided below:

Response to Item 1:

Originally, flexibility of the base plate was not specifically taken into account in detennining the concrete anchor bolt loads. Alabama Power Company is in the process of performing a design review that takes base plate flexibility into account in determining the concrete anchor bcit loads. This design review is described below.

Grinnell, Southern Company Services, Inc. (SCS) and Bechtel Power Corporation (as appropriate) are utilizing the calculated Westinghouse /Bechtel piping system hanger / seismic restraint design loads and the ICES STRUDL Program to develop design loading conditions (forces and moments) at the centroid of each attachment to the hanger / seismic restraint base plates. For simple cases the forces and moments are obtained by hand calculations. Bechtel then utilizes this information in conjunction with the inspection and test data for analyses of all base plate anchor bolts to determine if the existing t'ase plate anchorage is adequate to meet the design loads with the prescribed safety factor or if corrective action is necessary. This determination is performed in accordance with FNP-1-ETP-123 (a Farley Nuclear Plant Engineering Technical Procedure) which has been reviewed by NRC, I&E Region II Staff.

More specifically, a summary of the evaluation of base plate design by Bechtel is as follows:

1. The method of analysis is based on an empirical-analytic technique developed by Bechtel which takes into account design parameters such as flexibility of the base plate and concrete anchor stiffness (based on actual pre-loaded load-displacement curves furnished by the manufacturer). This method has been verified with appropriate finite element analytical solutions. Description of this empirical-analytic technique is provided in Attachment I.

A computer program for the empirical-analytical technique has been implemented for determinino the anchor bolt loads for the majority of applications. For other cases -der to Item 3 below. This program requires plate dimensions, number of .solts, bolt size, bolt spacing, bolt stiffness, the applied forces and tk allowable bolt shear and tension loads as inputs.

TL allowable loads for a given bolt are determined based on the concrete edge distance, bolt spacing, embedment length, shear cone overlapping, manufacturer's ultimate capacity, and safety factor.

The program computes the forces on the bolt and calculates a shear-tension interaction based on allowable loads. An interaction value greater than the allowable is accepted as failure of the bolt (safety factor less than required).

Unit 1 shear-tension interaction analyses are computed utilizing a linear rel a tion. Even though a subsequent squared interaction formula is acceptable and its use has been justified by Bechtel in representing the shear-tension interactiori, Alabama Power has chosen to continue with the use of linear relation ship recognizing that the results from this technique are more conservative.

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The empirical-analytic method does not consider prying action for the follow-

!ng reasons:

a. Where the anchorage system capacity is governed by the concrete sSear cone, the prying action would result in an application of an external compressive load on the cone and would not affect the anchorage capacity,

b. Where the bolt pull out determines the anchorage capacity, the additional load carried by the bolt due to the prying action will be self-limiting since the bolt stiffness decreases with increasing load. At higher loads the bolt extensions will be such that the corners of the base plate will

- separate from the concrete and the prying action will be relieved. This phenomena has been found to occur even when the bolt stiffnesses in the finite element analysis were varied from a high to a low value correspondin to both typical initial stiffnesses and to values beyond the allowable design load.

2. Calculated boit loads are used to check stresses in tho support base plate to ensure they are less than the allowable stress as specified by the American Institute of Steel Construction (AISC) code.

3. For special cases where the design of the support plate does not lend itself to this method, standard engineering analytical techniques with conservative assumptiot.s are being employed.

All anchor bolts within the scope of this program shall be evaluated by Bechtel in a cordance with the bolt acceptance criteria, current "as built" drawings, and the bolt design loads to determine if corrective action is required.

If any bolt on a base plate fails the acceptance criteria described above, one or more of the fnllowing actions are being taken:

a. Re-analyze the base piate assuming that the bolt is failed (bolts carries zero load).

o. Re-analyze the base plate incorporating bolt replacement as corrective action.

c. In those instances where repair corrective actions result in a piping support modification, Bechtel/ Westinghouse (as appropriate) will analyze the effect of such modifications on the analysis of the piping system.

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. Response to Item 2-In general, the currtnt industry approach concerning the use of safety factors for various design loading conditions are described below:

1. Factors of safety (i.e. ratio of bolt ultimate capacity to design load) of four for wedge type and shell type anchor bolts, for service (operating) load cases,are used.

2. For factored loadings (which include accident / extreme environmental loads) safety factors of 1.2 and 3.0 are used comensurate with the provisions of Section B.7.2 of the Proposed Adcition to Code Requirements for Nuclear Safety Related Concrete Structures ( ACI-349-76) August,1978. The factors of safety are consistent with the ultimate strength design method. A factor of safety of 1.2 is used if the failure mechanisrd for the anchor is controlled by the bolt material . If the failure mechanism is controlled by concrete shear cone action, a factor of safety of 3.0 is used. The utilization of sampling and quality control methods used are integral to selecting the factor of safety of 3.0.

3. For general structural design in steel, the AISC Specification has an approxi-mate factor of safety of 1.7 for services loading (for example, column buckling).

For factored accident / extreme environmental loads, a factor of safety of 1.1 is used on nuclear structures for both ductile (yielding) and non-ductile (column buckling) failures. In concrete design for factored loads, a factor of safety of 1.1 is used for flexural and tension action and 1.2 for shear action.

It can be observed that a higher factor of safety is assigned to the expansion

- anchor only if its capacity is governed by the shear cone.

Based on the aboveinteraction of design parameters and on the following addi-tional factors, Alabama Power Company has concluded that a safety factor of 2 is sufficient to ensure operability of Seismic Category I piping system in the event of a seismic event:

a. 1007, verification testing program with total Quality Control coverage of scoped systems (described in question 4) which minimizes installation uncertainties (e.g. verification of torque, embedment depth, nut engagement, plate configuration, expansion of shell, etc.)

b. Verification that plates are not overstressed by bolt loadings (e.g. con-sideration of minimum edge distance and proper bolt spacing).

I Response to Item 3:

In the original design of the piping systems Bechtel/ Westinghouse considered deadweight, thermal stresses, seismic loads, and dynamic loads (e.g. certain rapid valve openings and closings) in the generation of the static equivalent pipe support design loads. -

The safety factors used for concrete expansion anchors, installed on supports for safety related piping systems, were not increased for loads which are cyclic in nature. The use of the same safety factor for cyclic and static loads is based on the Fast Flux Test Facility (FFTF) Tests *. The test results indicate:

1. The expansion anchors successfully withstood two million cycles of long term fatigue loading at a maximum intensity of 0.20 of the static ultimate ca pa ci ty. When the maximum load intensity was steadily increased beyond the aforementioned value and cycled for 2,000 times at each load step, the observed failure load was about the same as the static ultimate capacity.

2. The dynamic load capacity of the expansion anchors, under simulated seismic loading, was about the same as their corresponding static ultimate capacities.

• Drilled - In Expansion Bolts Under Static and Alternating Loads, Report No. BR-5853-C-4, Rev.1, by Bechtel Power Corporation, October 1976.

• • a

I Response to Item 4:

Since existing Q.C. documentation is not adequate to document the installa-

7. ion parameters associated with each anchor bolt, the following programs have been undertaken: -

Test Program Alabama Power Company initiated a program to randomly select and test a sample of anchor bolts installed in Seismic Category I, Safety Related, 2h inch and greater piping systems. Initial results of that program revealed that statistical sampling would not be sufficient to provide a 95% confidence level in anchor bolt reliability.

As a result, the anchor bolt testing program was expanded to include 100% verifi-cation of anchorages associated with pipe hangers for those systems or portions of systems required to meet design basis accidents and those required to bring the plant to cold shutdown condition. These piping systems included in the program are:

a. Seismic Category I; Safety Related 2h inches and above.

b. Seismic Category I; Safety Related ASME Section III, Class 1 piping, under 25 inch.

c. Seismic Category I; Safety Related of other classes for which the designer performed detailed analysis,

d. All piping through containment penetrations.

The scope of this program given above has been reviewed and approved by the NRC I&E Region II Staff.

The specific systems involved in this testing program are listed in LER 79-21/0lT Anchor bolts on hangers within the scope of this program are tested for the following parameters:

a. embedment - Actual embedment depth is determined.

b. grout - The presence of grout and levelin nuts is determined to ensure proper torque test.

c. type of bolts - Verification is made that installed bolts are in accordance with design bill of material.

d. number of bolts - Verification is made that the installed number of tolts is in accordance with design bill of enerial.

e. bolt dimensional measurements - Dimensional measurements are taken to determine the degree of compliance with the manufacturers' recomended bolt installation requirements.

f. torque - Bolts are torqued to a level such that the resultant tensile load on the anchor is equal to k of the manufacturers' published pull-out load. For sc. ell type bolt torque tests to be considered valid, the shell shoulder must nc t touch the base plate.

7- 1 rg

NOTE: A torque / tension relationship r s developed for Hilti wedge type anchors

( based on tests performed at Farley. Torque / tension relationships were developed for Phillips shell type anchors under the direction of Bechtel Corporatic.r vWh tech.ical censultation from ITT-Phillips Drill Division at Plant Hatch. Since these relationships were completed and the majority of anchor bolt field veri-fication was performed prior to I&E Bulletin 79-02 Revision 1 issuance, no site specific testing for the shell type anchors was performed. Torque requirements for Wej-it wedge type anchors were obtained from vendor data.

9 base plate dimensional measurements - Dimensional measurements of base plate parameters which could affect bolt loading or capacity (e.g. bolt spacing, edge distance) are taken.

Based on the results of the test program and the empirical-analytic evaluation, anchors are being repaired according to the following criteria:

i. Repair individual base plate anchorages not having a safety factor of at least 2.0.

ii. Repairs are done so that all repaired bolts have a safety factor of at least 4.0 and all base plate anchorages have a safety factor s ' at least 2.0.

iii. All repairs are done in accordance with written procedures and quality control checks.

The failure to test inaccessible anchor bolts will be justified by analysis which substantiates operability of the affected systams without assuming integrity of the anchorages which are not tested.

Preloading Available test data indicates that it is not necessary that the bolt preload should be equal to or greater than the bolt design load because pipe supports and anchors are subjected to both static and dynamic loads. The dynamic loads such as seismic loads are short duration cyclic loads and are not fatigue type loads, therefore the amount of preload on the bolts will not greatly affect the perform-ence of the anchorage. The initial installation torque on the bolt accomplishes the purpose of setting the anchor, but the ultimate capacity of the bolt is not affected by the amount of preload present in the bolt at the time of cyclic loading. For vibratory loads, the expansion anchors have successfully withstood long term fatigue conditions as discussed in the previous section (FFTF tests).

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Response to Item 5:

The Alabama Power Company testing, analysis, and repair program will not be completed by July 6,1979; however, Farley Nuclear Plant Unit 1 is currently shutdown during the present critical power deraand period to complete the above crogram. The testing, analysis and repair program described in Item 4 will be completed prior to return to power generation.

Documentation of the program will be maintained on site.

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Response to Item 6:

A similar program for the verification of Unit 2 anchorages will be developed as the result of experience gained from Unit 1 activities.

A full description of this program will be transmitted to NRC oy'a supp'ement to this bulletin response. Such verification program will be completed prior to initial criticality. Currently, the construction activities associated with Unit 2 are temporarily suspended due to the Company's financial condition.

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ATTAGMENT I 4

DETERMINATION OF EXPANSION ANGOR BOLT LOADS IN PIPE SUPPORT BASE PLATES

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Summarl This report deals with the determination of anchor bolt loads in steel base plates supporting Soismic Category I piping systema.

The anchora in question are of the expansion type. The loads are applied to the base plate through some type of httachme~nts, usually concentric with the base plate, and could comprise of moments and foreca in three directions. A review of the typical base plates used in supporting the subject piping systems indicate that the ms.iority of them have either a 4,'6 or 8 bolt connection. The plate tiicknesses usually vary from 1/2" to 1 l/ f and are not generally stif fened. The present fornu-lation will, therefore, be devoted to base plate anchorage systems with afore-nentioned physical characteristics.

From a purely analytical standpoint the load distribution in a base plate anchorage system is f airly compicx and it is necessary, therefore, that certain simplifying sasmptions be made to arrive at conservative yet practical solu-tions. However, such assutnptions should take into consideration the following parameters which might aff ect the load distribution in the anchorage system.

a. Plexibility of the base plates considering the bending effects.

b. Eolt stiffness: to be based on actual preloaded load displacement curves as furni,shed by the manufacturer.

e. Prying a(tion .

For expansion anchor bolts prying act. ion will not be critical for,the following reasons: .

a. Where the anchorage system capacity is governed by the concrete shear cone, the prying action would result in an application of an external cocipressive load on the cone and would not therefore af fect the anchorage capacity,

b. Where the bolt pull out determines the anchorage capacity, the additional load carried by the. bolt due to the prying action will be self-liciting since the bolt stif fness decreases with increasing load. At higher loads the bolt extension will be such that the corners of the bsse plate will lift off and the prying action vill be relieved. This pher.onena has been found to occur when the bolt stiffnesses in the Finite Element Analysia were varied from a high to a low valus.

Method of _ Analysis for Anchor Bolt 1.ceds_:

In gc -ral, the Finite Element Method of Analysis may be used to analyze the base plates under consideration. However, such an approach will be both time consuming and expensive considering the number of base plates involved. A quasi analytical approach has been formulated taking into account the base plate flexibility and the bolt stif fness. The results of the analytical solu-

' tion have been verified with appropriate Finite Elsaent solutions and have shown good correlation for the typical cases studiesl, ,

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a Aa }M 3 3 -.... .~.~ ...~. ... ........ ....,~.....

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INTRODUCTION:

THE PURPOSE OF THis STUDY WAS TO DEVELOP AN ANALYTICAL u METHOD FOR DETERMINING TENSION LOADS ON EXPANSION ANCHURS USED AS ANCHORS FOR PIPE SUPPORT BASF. PL AT ES. .

FINITE ELEMENT ANALYSES (REF-1) SERVED AS A DATA B~ASE FOR DEVELOPING LESS EXPENSIVE. AND LESS TIME CONSUMING AN ALYTIC AL, METHODS. THE METHOD WHICH 15 PRESENTED AS A RESULT OF THIS ' STUDY USES PLATE FLEXIBILITY AND BOLT STIFFNESS AS THE PRIMARY PARAMETERS. THIS METHOD WILL BE COMPUTERIZED FOR 4,648-BOLT PA7 T E R NS.

__ ANALYSIS :

IN THE QUASI ANALYTICAL MODEL PRESENTED HERE.T14E PLATE  :

15 PRIMARILY TRE ATED AS A BE AM ON ELASTIC SPRINGS.

BASE PL ATES WITH THREE DIFFERENT BOLT CONFIGUR ATIONS HAVE BEEN CONSIDERED.

. ASSUMPTIONS-(o) SYMMETRICAL BOLT PATTERNS (b) CENTRO!DAL LOADING (c) ATTACHMENT DIMENSIONS SMALL COMPARED TO THE PLATE DIMEN SIONS (d) UNITS FOR ALL VARIABLES:

FORCES KIPS LENGTH INCHES l l

g

, _jdh a db .j UL U 3- 3_. .. .... . .... . .... .....

4 m

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j (3) 4-BOLT PATTERN - MOMENT AND TENSION LOADING CASES t-j GIVE.N A PLA7E WITH A 4-BOLT PATTERN AND A MOMENT l

ABOUT ONE AXISI THIS PLATE WILL BE MODELED AS A '

~

BEA14 _j m

d l+ -- j A

+ + 1 4

M $

~ h i

+ t l A

k

?

3 EECT'ON A- A ..

y

-&j' -

=.

~

WHERE:

• L_ w '

TiTOTAL TENSION (KIP) .;

J JJ J

/\

' '/$ j Cs RESULT ANT OF  :

s t

COMPRESSIVE STRESS j BLOCK (KIP) d 1 c T (x) c(x) = M i, a

. y - -

a. =

o' 4 n l% . ..-.....-........ .... .... ............

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THE BE AM WILL BE IDE ALIZED AS BEING SUPPORTED AT THE LOCATION OF THE COMPRE6SIVE FORCE RESULTANT. THEREFORE, IF THE COMPRESSION CENTROID CAN BE LOCATED,TBECOMES ..

KNOWW AND"T' CAN BE CALCULATED.

M Kgs BOLT O

fff 4 STIFFNESS h T X: M o

T C I

I N l l

FOR A 4-BOLT PATTERtJ LOADED CENTROIDALLY

-+ +

i

. . X* h + h2 + L

• 4 m

4 I a

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~~

,[_ ~

/r / [/ (ENTf,Olb

<44 ,

b COMPRESSION 20NE  :

.c 0

. I - S . ...~. ... .

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V,;: l'.i T UAL LY, 1,.

' I3 Ai

1. 1 I UNCTION (t,d,Kg) i .

] . d i'(Uj j [b la o LilJ l'GIE R E ,

L. DISTANCE FROM EDGE OF ATTACHMENT TO THE CENTER OF -

CQMPRESSION (IN.)

t * '3L AT E 7HICKNESS (IN.)

d= 0lST ANCE FROM EDGE OF ATTACHMENT TO THE EDGE OF THE PL ATE (IN) r7 EsOLT SilFFilESS (K/IN.)

btSED Cli A NUMBER OF FINITE ELEMENT ANALYSIS RESULTS (u . V A f,YING T,d a K3 ), THE FOLLOWING EMPIRIC AL REL ATIONSHIP IYAL DE R!VE D :

(i)

L: S.S [(h)$ (%3)](d)

WHERE L&d ONCE L IS CALCULATED, TOTAL TENSION (T) AND BOLT LOAD (f i) CAN BE FOUND:

M (2) l'h 4 h 4L M

(3)

F1 'I '54b42L 2 FOR CENTROIDALLY LOADED 4-BOLT PATTERNS ONLY TH!S METHOD CAN BE EXTRAPOLATED FOR USE WITH COMEINED LOADING CASES.

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I FOR BIAXIAL BENDING:

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D (4)

CRITICAL F) = g,g g, + 4 + 4 2W F; } g ^nf 7 o C a b J l@J J U[/b ,

FORIDJsB111ED_ BENDING AND TENSION:

M T CRITICAL Fe g,n

• T (5)

SINCE L VARIES WITH t,d r4 K, THE METHOD FOR FINDING L C AN BE USED FOR MANY PLATE AND BOLT PATTERNS. ONCE L 15 KNOWN

' THE PLATE CAN BE MODELED AS A BE AM ON SPRINGS. THE BE AM CAN BE SOLVED BY VARIOUS METHODS AND THE TOTAL T EN SION FORCE FOR AN.Y ROW OF BOLT 5 CAN BE CALCUL ATED.

THIS WILL BE DEMONSTRATED FOR SIX AND EIGHT ' BOLT PAlTERNS IN THE FOLLOWING DETAILS.

Q) B-BOLT PATT ERN - MOMENT LOADING CASE _

- .. .. N. -. w

+ + + BOLT ROW 'A*

[

m Y

+ -

+ BOLT ROW "B' f

m.

._E f ~ +< +e +h BOLT ROW *C" .

~

~

n-

8 j

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i 2

J /.1/ M G 'O E L :

j

~

E j

9IU)l@l7 ]p.

j

~

M .L Ofu J (, uj g' g( gg {,

9i i

_ . _ . _ . - .C- '

A,j B

-i

? K, fK 2 e m D7

! (COMPRESSION CENTROID  ;

9

. . . _ . . _5 I

ib .

Kas BOLT STIFFNESS j I

• Nt*

12 i

i T Hi. RL A'.TIONS FOR THIS INDETERMINATE BEAM MODEL CAN BE S01 VCD USING VIRT UAL WORK PRINCIPLE. THE FOLLOWING _

E QllATIONS WERE DERIVED FOR B-BOLT PATTERNS:

WHERE L IS DETERM!NED FROM EQ (I) l E$ k+L EIi 411 W t * (KIP IN*)

11 R'.DUNDANTS ARE TAKEN AT Y:

El 6c,= E k Krh g, .

3 .._QES 3

(6) t 1

WHERE 6ce, IS THE DEFLECTION AT 'C' DUE ONLY TO 'M":

- i EI + yE [1+ S] (7)

EI Scc

• s'N,Kg [. k S + 2 K,2 S * (K;* kg)E',,

i f

WHE RE Scc 15 THE DEFl.EETlDN DUE TO A l* FORCE APPLIED AT

'* (B)

REA Tl0N AT C = Rc = -

.'. R 4= -[M -2 (Re)] ; R g = Re- R A q 3- '

J

-o 3 (

l-s ..

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At 1Hl. PLAT E GETS WIDER AND E BECOMES SMALL COMPARED T(. Y, T HE TWO MIDDLE BOLTS CANNOT BE LUMPED TOGETHER Ai ONE SUPPORT WITH K2= 2Kg. Kz WILL BE SOMETHING LESS T H/,N 2Kg. THE FOLLOWING EXPRESSION FOR K2 YlELDED Rl"Sul.TS WHICH WERE IN GOOD AGREEMENT WITH FEM RESULTS: ,

(9)

K=2Kg(})*6.2Kg 2

FC' PL ATE SIZES GENERALLY USED IN PIPE SUPPORTS, THIS Wil TH EFFEET WILL HAVE NEGLIGlBLE EFFECT ON ROW "A' l.e.

THL !.Til FNESSES OF THE AREE BOLTS CAN STILL BE LUl6[i TOGE THER IN THE BEAM MODEL.

l Hi. fii3 (. T IC NS IN THE BEAM MODEL ARE NOW kNOWN. THE RI: AC TION AT ANY ONE SUPPORT IS THE TOTAL TENSION IN THAT F OW OF BOLTS. TO DISTRIBUTE THE LOAD TO THE 80l'S:

F C:8 R06 "B' FROM SYMMETRY, Tl N510h PER BOLT = TF ;FT e

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FCS R3W "A",THE RELATIVE STIFFNESS OF THE PL ATE AND 1 H i. BCLTS AND THE BOLT DIST ANCE FROM THE All A.C HME NT WILL AFFECT THE LOAD DlSTRIBUTION BET WEEN THE MIDDLE AND THE CORNER BOLTS.

I EVIDENT LY THE BOLT CLOSEST TO THE ATTACHMENT WILL CARFsY MORE LOAD AND IF THE ATTACHMENT SIZE IS SMALL, BOLT TO THE ATTACHMENT DISTANCE MAY BE SUBSTITUTED BY THE DISTANCE OF THE BOLT TO THI, CENTER LINE OF THE 'PL ATE. THUS TENSION IN THI lDDLE BOLT '9:

(11)

Fu q (R4) h E. bN* EN_ he_

WHERE: Lm= DISTANCE FROM PLATE CENTER TO BOLT 9 '

Le s DISTANCE FROM PLATE CENTER TO BOLTSiin*c'

$$[3) d W D D d[i A=5*E i

e(. CONSTANT p

[> ib: aoj ta r ,- ,

cq w UO ] 7]L Ub J

. l .". 3. . .. . . . . . . . . ,

10

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M eel, ON SEVERAL FEM ANALYSES THE FOLLOWING EXPRESSION OF F 1 t. Vs'A5 . ARRIVED AT: . , -

bA} (

IT E . A ( AR ) ' bs y t

Ps'ITil T HE LIMITS 0.333 ch 41.0 CORRESPONDING T O VER.Y RIGID AND VERY FLEXIBLE PLATES.

T l'.N E lCI ' IN THE CORNER BOLTS IS GIVEN BY :

F3 ,s f h

• F#hfIE-(l3)

At;: Fy Tg:Fih i *O M F C I. E :/- Y!AL E>ENDING , THE RESULT ANT BOLT FORCES WILL EI DETI RMINED BY SUPERPOSITION.

T (E j .f. Cj.,7 P_ATTERN- MOMENT LOADING C ASE L X

o

+ + +- T -

+ + + o

' i 5y

. b, SY .. - ._ , ,_

BY p.. . _ _ _ _ _ . _ _

THE 6-BOLT PATTERN CAN BE SOLVED BY USING A COMBIN ATION -

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01 THE'. EQUATIONS FOR 4 BOLT AND 8-BOLT PATTERNS. .

onTn Maj o

To~

W '3 o

1 g s) 70 a J1) d.]

_ _ iL l-10

11

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FOR MOMENT ABOUT THE X-X Axis:

(A) USE ' EQUATIONS (1) AND (2) TO 60LVE FOR TOTAL TENSION .

(B) USE THE B BOLT DISTRIBUTION EQUATIONS (12) AND (13)

FOR SOLVING THE BOLT LOADS h7TH 2,=y + E 4 EI 2417 B yt';

FOR t[OMENT ABOUT THE Y-Y AXIS:

(A) USE EQUATIONS (6),(7) AND (B) TO SOLVE FOR REACTIONS 8

WIT H Kr

• 2 6K (j)'; S= Sy ; Ya y ; EI 241T 6xt (B) D! VIDE THE RE ACT!QNS CORRESPONDING TO EACH BOLT ROW BY 2 TO OBTAIN INDIVIDUAL BOLT LOADS.

(D) 6 AND_8 BOLT PAT TERNS , TENSION LfgD8NG C ASES:

UNLikE THE 4-EOLT PATTERN, FOR THE 6 r,6 BOLT CASES THE EENTRALLY APPLIED TENSION CANNOT BE DISTRIBUTED E QU At.t.Y 10 ALL THE BOLTS DUE TO THE INTERPLAY OF BOLT AND PL ATE STIF F NESS E S AND THE REL ATIVE DISTANCES OF THE BOLT 5 FROM THE POINT OF APPLICATION OF THE LOAD.

BASED ON THE MOMENT CASE IT WILL BE ASSUMED THAT THE PARAMETRIC VARI A'3LES AFFECTING T HE LOAD DISTRIBUTION WILL BE OF THE SAME FORM AS IN THE MOMENT EASE. THE CONSTANT $ FOR THE DISTRIBUTION FACTORS DFM, AND DFMy WAS OBTAINED FROM FINITE ELEMENT ANALYSIS RESULTS.

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12

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8-BOLT PATTERNS- TENSION LOADING C ASE:

L  ! l

' '?[FlQ['i/?[*

Ul. . ! d O uu ird b-j'

+- -+* $ 4 .

Y

%w -

)

f

-4 0 z

,-,-x x

\ T,/

v>

j T TENSION LOAD U

1 -g 40 4h Fi= LO AD PER BOLT i ~ '

i i CALCUL ATE:

8 Sy Sy EIr 2417 8xt EIz 2417 Byt 8 0

.......Y._._...

. M. EI, 8'

25y Ky,EI 2Sx gr T*' T ; Ty Mx

,k3 4ky ,

Le 5 (S 3)* * (Sy)* 4 ,

k(8 } 6 DFMx & I,00 DFMx= { I 7 EI

- -- 1 Lc-1 e Ks(25,)r 4 3

,g DFMy=3 EI 2 I 7 6 DF M y 41.00 g 4 Lg K

NOTE: FOR PLATE STIFFNESS VARY 1NG FROM INFINITELY RIGlD TO EXTREMELY FLEXIBLE: i e

$ 6 DFM4i SINCE A ' RIGID' PL ATE. DOES NOT EXIST, $ 7 WAS USED AS A LIMIT (

l-l t

13

. (

i I FgsFTe ' _DIMY ,

t ]{ (\ F Ljb 'b F7 a = F~ t e = [DFMx]_T f[ ,.

FT . FTe} FTt FTh' 4 .

=

IT BY AGOVE EQUATIONS7 F pFr OR F Tb ' f T. . SET F tp F7. OR Fw.Fw AS LIMITING VALUES FOR RECTANGULAR PLATES 6 BC)l.T PATTERN-TENSION LOADING CASE :

y

-+" $ +' k 4 .

l . ._ 'rx a

w g- #

[ d EI,c 2417 8xt' 4 4e 4 EI 2= 2417 6yt'

.} . _____.__....___.J_.._..______.._ ,

. ... 5.Y.

SY U K=Q 3

By

. ...._... ... .._ .-...... ..._.._ .

• EI; 5x IT* .dY. T DFMy= { 8 (S *

, f3 ,4 2ig_

akAND&l.OO

_ E I r ,,

8 W HF. RE Le= A)*

z d8J3 )'

F Tb" FT e = [DFMy][T 4]

'(

Fro Fc-FTd 7

• fif

• 4 BASED ON THE ABOVE EQUATION, IF FTa(= FTc ' F Td: Ip)>FT T b (* I Te),

AS MAY BE THE CASE WHERE 5xz 25y, THEN F oT aFTe=Fi g.FTP- ,.

FTb Fte = {

G

~O l-13

(- (IS$ COMPARISON _OF RE SULTS:

FINITE- E LEME NT METHOD VS BECHTEL MODEL >

5 SKETCNES OF BASE PL ATES ANALYSED: ,

+

(A)'4 - B.O_LT PAT T E R N -)

D

' ^

U Ib'-l ll i /] I y, l) .

1

. JiiUby/[j!

.' + + _ - _

Y J  :

7

- .*3; , .

ul

/ -

z/

i 8

4,,

. + , I 1 N Il 2' - 12". . - .. . . . . w 2'

- =

Il t ks LOADING l b' 41_ _ _ f,4 > i l 8 k " .

p A/ _ 44 Mi 16kildvux~

3 h* 44 Ma'IBk'.Fa*4M' 4 7# 44 Mr lB K' 5 fi l50 tAs=l8n" 6 I'/ 300 Mr lBk' Kg BOLT STIFFNESS (k/IN)

t. PL ATE THICKNESS 3

.; o -

k

(~li

(-

_4_ .8' ___ _ 14 _4 ~____ - ..w.dd

. -l- y  !-

Q g- [D')Il ff0 "i i) h. I j .y b

• g k!1j(OuLAJLIOd I

2 /t . . _ . ,

e i

+ 14 + ,

L_. wt

& t, Kg LOADING

' M y 217.Si' Ks= BOLT STif fliE55(k/Ild

-f V 44 44

~~

M v : 2 47.5 x" t = PLATE THICKt4ESS B 2" '~

9 k"~

44

~

$Nh'

~ ~ '

FROM TELEDYNE ENGINEERING REPORT (REFERENCE 0) .__

(b)(,-BOLT PATTERN:

_.31 ~

Sy __ w ___SY _-

t Kg= BOLT STif f NE SS(K/Ill)

-J

, .g 5 .. t= PL ATE THICKNESS

/- ~

o n-

.g s ,I LLJ +

y

+ + o Sy In 3Y LOADiffG lt t Ks Sr .'

- 1 I 44 12 8 16 _

f6 20 20 Ma*36"'

Mr: 3 6 "'_

(40 12 8 2 _l* 4 25.5 12 Fz.=10" 3 l' 44 22.5 4 25.5 12 fr.io" 2* 44 22.5 4

16 fr l0" s

5 T~ 44 ,_

l2 _ __6 16 16 F = ct a ' , __ ,

G 6 l' 44 P _6 16

, .[. er . . _ _ . _

U i

" ' iJ (C) B- BOLT PAT T E R N r,p Ep :

BY

- hLUlijUUu'//jlllglIh'lO J

. - =- -

Sy g Sy ___

, i

. +o +b +c g i i

~

i Y  :

J Wi I j u .

Yd /

1. Ye cI p l z#  :

y b--m.l g.

I

't i- + +- -

i 1

& t kg 53 sy Bx BY b I.0ADING l IV 44 12 12 28 28 6 M x = 180 "

._R IV 440 12 12 2B 2B [~1,s l 8p' 3 I" 300 8 8_ 20 20 !4 M x t 90"'

_[2.,_,, 28 2B ; 6_ F _i 16 5 4 -. 81. 15 0_ 12 .

5 _lS' 44 12 _ l2 28 28 6 F1 = 8" i

,,b., , _ l ' _d4 i 6 10 1 16 24 f .10" Ke BOLT STIFFNESS (KIP /IN) t PL ATE THICKt4E55 i <

b I

TAbt!! t.TE D RESULT S:

4-E011 P. alt E RN :

U(

5t ' '

~

. LOAD PER BOLT (M)

~" ANALYS65 BECHTEL I*

L1koD FINITE ANALYTICAL l E LE ME.NT MODEL DlF F E ret'CE PLATE I A O.15 0.75 0

.._- (1)

A (2) 2.08 2.25 + 8. 2 1.75 + P. 3 l j A (3) i.71 o.6 B < 6.3

[_A (4) 0.64 _

A (5) 0.75 0.78 44.0 i

i A (6) 0.78 0.B 4

• 7. 7

~

9.19 + 0. 8

!A (1) 9.12 6.12 6.45 + 5. 4 I A. iid 49.4 A (9) 16.61 1 18.17 _

(.- 6011_ PAT T E RN :

o TENSILE LOAD PER BOLT (k) f bcLT 6 6oLT BOLT 5 BOLT DIFFERENCE a t. c J og y

._\ AdT6'5 FINITE BECHTEL BOLTS BOLT MLW ' AN ALT T tC AL a LC b ELEMENT Moott PLATE N B (1) o.65 f.8 4 0.64 1.72 - 1. 5 - 6. 5 (2) 0.61 1.96 0.72 1.86 +18.0 - 5.1 B '

B (3) 1.6B l.64 1.61 f.67 - 0.7

• 1.5 B (4) 1.67 IA6 1.67 1.67 0 + 0.2 1.55 1.B9 1.67 l.67 + 7. 2 -13.5 -

B (5) ' "

1.45 1.59 1.5 1.5 + 3.2 - 6.1 B (6)

,f- "Y

.. M1 _.-..._.......:.._

DPTD 2

!a S [L

/ '

fiD ~lj: Fn] 'li V /i'~'l r 1

r Ec.L1 PAT't E Rt4 : ' ,

O J b NU //O _,

s

.. ~

TEN 51LE LOAO PER BOLT (H) p

'Goti ~ E~o'ET T b^r Ct' 3 6CT loTT-J.-} bogT DIF F E RE NC E A.... . . .. .s . _ _ . . . _ .

' . .4 bECHTEL BOLT BOLT BOLT

M. ., NE . - . . . .

FINIT E g g Atl ALYTIC AL ,

ELEMEf4T MODEL i i F i f.l ENN; + 2.69 + 2.5 + 17.0

i.59 2.64 ' O.75 1.94 2.70 oj2 ,

! (. (I) 1.47 - 2.3 + 0.7

$.26 f.46 1.56 5.14 11.9 C (2) ..-__  : 1.55 - 3.0 3.23 O.85 + B.2 - 2.6 3.32 o.88 - l. 32 j,( ( 3) ,_, ,,

I.22 _

2.92 1.46 0 0 0_

C (4) 1.08_ 2.92 ... . 1,46 1.08 ...

-3.5

+ 3. .6 . . . -. 2.6

....._. 0.57

- 0.59 0.86 1.14 . . . . . . . . , -

0.83.. . 1.17. . . . _ _ _ .. . . _ _ .

C . (. 5_) .

- 3.1 + 4.4 - 5.2 0.99 1.95 1.06 0.96 2.04 1.01 C (6) 1 e i 1

- i

./

-4 i Th e'

\-t s . .......................... .

. PE

$[ @

L tu! ,. ._a M

O lei O

[P

1. " '#j (( "[ '

REFETENC S

~

Ng

-- f 1,ANSYS" ENGINEERING ANALYSIS SYSTEM, DEVELOPED f3 ifj BY SWANSON ANALYSIS SYSTEM,lNC.  %

2. DILUNA, L.J. AND FL AHERTY, J. A.,"AN_ ASSE SSMENT jj OF THE AFFECT OF PL ATE FLEXIBILITY ON THE j}

DE SIGN OF MOMENT- RE SIST ANT BASE PLATES';

'j TELEDYNE ENGINEERING SERVICE S (SU3MITTED ;j TO ASME FOR PUBLIC ATION) b i

• i

l4 e

9 I }

n e - .

o g

I-l9

..