ML20127C222

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Discusses Availability of Info on Shear That Is Applicable to Facility Basemat.No Excuse Found for Departing Radically from Code Provisions,But Advantage Should Be Taken of Provisions in Code Allowing Increase in Shear Strength
ML20127C222
Person / Time
Site: Waterford Entergy icon.png
Issue date: 05/14/1984
From: Philleo R
AFFILIATION NOT ASSIGNED
To: Shao L
NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
Shared Package
ML17198A241 List: ... further results
References
FOIA-84-455 NUDOCS 8506220171
Download: ML20127C222 (16)
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ROBERT E. PHILLEO. P.E. i CONSULTING ENGINEER

, 7410 ANNANWOOO COURT ANNANDALE. VIRG!NIA 22003 May 14,1984 s

i Mr. Lawrence C. Shao Deputy Director Division of Engineering Technology U.S. Ituclear Regulatory Commission Washin'gton, D. C. 20555 .

Dear Larry:

I have looked at what is available on shear that is applicable to' the Waterford basemat. I also talked to Dick White. He was of the opinion that his work on in-plane membrane shear stresses was not particularly applicable to the case in hand. We also agreed that there ,

is not much work that is specifically applicable to a 12-ft thick mat on' the ground.

I'erguson's work, cited in the ACI-ASE cor. ittee 426 report ead reproduced on the attached sheet, shows that for steel percentages'of 1 and above the data for shear strength, with one exception, were in the range of 2.1 to 2.5 % . Of perhaps greater interest is the fact that' Section 11.3.2.1 of the 1983 ACI Code allows shear stress in the concrete as high as 3.5 (Fc when the ratio of bending morent to shear at the critical cross-section is low.

The two papers distributed by Ma bear some consideration. The paper by Kani is discussed in the cotnmittee r9 port. The report tends to disregard its implicat. ions and to base -its conclusions relevant to deep beams on the depth .idth ratio rather 'han on the absolute depth. Kcni did perform one test which purported to show that it was depth, per se, which nattered. Ferguson makes two points. The first has to do with the ,

reduction in shear resistance . Sear points of inflection and apparently is not relevant to the present case. The second has to do with a reduction in strength when small percentages of high-strength steel are used. It may be worth examining. ,

In summary, I can find no 4xcuse for departing radically frcct code g provisions, but every advantage should be taken of special provisions in the code which allow an increaia in shear strength under certain 7 circunstances. ,

FREEDOR dF lbFORM ATiON Sincerely, .

ACTREQUES(

Robert E, Pt.111eo, St-4rr 62 1 850222 GARDE 84-455 PDR Consulting Engineer Ch%

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Comments on Chen Report pin The facts concerning soil support,' ground water level, and construction procedures are apparently correct, although I cannot verify them in detail from my own knowledge.

The major a;onclusion that cracks in the foundation mat "have been caused or further aggravated by differential settlement" is probably correct, but it gives no indication as'to the magnitude of the effect. While there were differences in the support offered by different parts of the foundation, a 12-foot deep besa could bridge over substantial regions with no support at all with only a minor effect or stresses. The most significant effect of foundation compressibility is the overall curvature in the north-south direction which produced a concave-downward final configuration of the sat with a maximum deflection in the middle strip of 2.5 inches. This shape was the natural result of placing the middle strip first and working toward the outside. The middle strip started to compress the foundation early and had nearly stabilized when the outer blocks were placed. The latter continued to settle with respe:t to the middle strip. Such a curvature would produce an average st ain of 70 x 10-6 in.the outer fiber of a 12-foot thick section. In the concave downward position this strain would be tensile in the top surface and compressive in the bottom surface. While this strain is not sufficient to crack the concrete, it would " aggravate" cracking from other causes. It would explain why cracking occurs preferentially in the east-west direction and'it would predict more cracking on the top surface than'on the bottom. The basic cause of the cracking is not dealt with except for a single reference to " thermal or shrinkage" on page 8.

I see no justification for the recommendation that a precisa measuring program for differential settlements be undertaken. The existing program is sufficient to demonstrate that the sat is stable. The precision of the existing system is adequate to~ demonstrate that stress in the concrete is not changing appreciably.

F Robert E. Philleo FREEDOW OF INFORMATION ACI REQUEST 9 '+- 455*

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Comments on Ma Report The reasoning in the report proceeds correctly from the assumption that there are very large discontinuities between adjacent blocks as a result of differential settlement, but this assumption requires examination. It is apparently based on the observation on Page 4, line 2 that "each newly poured block experienced an immediate settlement of about 3/4 of an inch while the existing blocks adjacent to it settled to a much lesser extent." There obviously is not a 3/4 inch discontinuty at the interface between two blocks because the top surface is continuous across the joint without offset and the steel crossing the joint would prevent any appreciable relative movement. The settlement readings I am familiar with were taken at the center of each block. The center to center distance between blocks is about 75 feet. A relative vertical displacement of 3/4 inch between the center of two adjacent 12-foot thick blocks could be accommodated in pure bending with negligible shear and an outer fiber strain of about 150 x 10 6 This calculation assumes no rotation by the existing slab, the worst condition. Any rotation or settlement by the existing block would reduce the strain below the calculated value. The value of 150 x 10 -61s approximately the value required to crack the concrete.

The above effect produces a concave downward shape. The final shape is also ~

concave downward with'a strain of about 70 x 10-6 If the above stresses did exist they were relieved as the sat achieved its final shape. In all cases the shape is such so as to produce tension in the top of the mat and compression in the bottom. Thus, it is difficult to understand the explanation of through cracks, as noted at the bottom of page 4, which postulates flexural cracks in the bottom of the mat. Flexural cracks should only exist in the top.

If cracking is to be attributed only to loads resulting from non-uniform foundation conditions, it is difficult to rationalize shear cracks in the  ;

central portion of the mat. This should be in an area of low shear stress.

I do not think non-destructive testing should be undertaken until a stronger hypothesis can be established for shear cracking.

FRE2DOnt OF fMFORMATf0N AGE MQUESl i Robert E. Philleo p gy C-flS l

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Temperature Cracking in Basemat The basemat concrete contained 517 lb of cement per cubic yard. Assuming a heat of hydration of 126 BTU per pound during the period in which temperature is rising and a specific heat for the concrete of 0.2, the maximum temperature rise is:

AT= 517 x 126 = 81*F 0.2 x 4.00 , . -

Assuming a coefficient of thermal expansion of 6 x 10 -6 for the strain to be accommodated is b = 81 x 6 x 10 6 = 486 x 10 6 Because of the low modulus of elasticity and high creep capacity during its early life the concrete may be assumed to reach its peak termperature in a nearly stress-free condition. During the period of temperature drop tensile stress will develop, but this stress will also' be minimized by fairly high creep.

A reasonable assumption is an effective modulus of elasticity of 1.5 x 10 6 psi (which takes into account the effect of creep),a tensile strength of 400 psi, and a temperature drop to final stable temperature equal to the original temperature rise.

The strain which can be accommodated by the concrete is E " 400 1.5 x 10 6 = 267 x 10-6 Since the potential strain to be accommodated is 486 x 10 -6, cracking will begin when a little more than half the cooling has occurred, and ultimately a strain Of FREEL/CM OF INFGet. .. , yN 486 x 104 - 267 x 10-6 = 221 x 10-6 ACT REQUEST Swsr c [7su

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will be accommodated by cracking. In in unreinforced mat this would produce a 0.01 inch crack every

.01 = 45 inches 221 x 10 -6 in random directions. Each 1% of reinforcing steel will reduce the crack width by about 20% and will hold the structure tightTy together.

It should be noted that these strains must be added to any others present in the basemat. Outer' fiber strains a,ttributable to non-uniform foundation compressibility may be estimated at ' values from 70 to 150 x 10-6, depending on the assumptions made. Adding these strains to thermal strains would increase cracking potential somewhat in the top of the mat and cause cracking to occur preferentially in the East-West direction. It would

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greatly reduce cracking Jn the,Kott'om of 'the mat. ~

In addition to these major cracks which occur as the mass cools slowly to its final temperature, there are cracks which occur early and result from e

non-linear temperature gradients when the concrete cools at the surface while it is still subjected to temperature rise in the interior. These are shallow and are the cracks which were discovered on vertical surfaces when forms were stripped.

Robert E. Philleo FREEbuM ur IN r u n M.s iois AGI REQUEST T+-V rs' C-/ ~7 72 -

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b Caution Notice This standard is being pre.

2 pared or reviewed and has not been approved 3 by The American National Standards Institute.

4 It is subject to revision or withdrawal before 5 issue.

6 7 REQUIREMENTS FOR AUDITING

^

8 OF QUALITY ASSURANCE PROGRAMS .

9 FOR NUCLEAR POWER PLANTS 10 .

11 1. INTRODUCTION

- . , _ : ;. 2 12 1.1 Sco pe. This standard provides requirements and guidance for estab-13 11shing and implementing a system of internal and external audits of 14 quality assurance programs for nuclear power plants, including the i

15 preparation, performince, reporting, and followup of audits. of. quality.

16 assurance. programs .fo r.nuclea s. power . plants The activities.covesed.

17 by this standard include deelgaing, pn.rchas.Ing,. fabricating handling,

.-.. ..' , 18 shipplag .stosing, cleaatag,-exacting,. Lnstalling,. Inspecting., . tasting.,

(# 19 maintaining, .respaising, and.modliying of.Nucleas Power. 21 ants.

20 21 This star.dard amplifies the audit requirements of American -

22 , National Standard N45. 2 and shall be used in conjunction with that stand-23 ard. -

24 -

25 1. 2 Applicability. The requirements of this standard apply to both internal 26 and external audits performed by or for the plant owner, contractors, and 27 other organizations participating in activities affecting the quality of i 28 structures, systems, and components of nuclear power plants which are 29 s ec ecordance with requirments of ANSI N45,213ht rffer -c -

30 sta dard is not applicable to survelliance or inspections for the purpose e

, , 31 of process control or product acceptance.

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Draft 3. Rev. 4

((j 1- Februa ry 22, 1974

, FREEDOM OF INFORMATION

, ACT REQUEST ,

. ..C j!783

1 Intarnal Audits Audits of thcoa.portiens' of an organt' zation's Qua1Lty 2 Assurance quality assurance program retained under its direct control .,

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3 and within its organizational structure.

4 5 External Audits . Audits of those portions of an organization's Qua1Lty 6 Assurance quality assurance program not retained under its direct control 7 and not within its organizational structure.

8 9 Other terms and their definitions are contained in ANSI N45.2.10 10 NOTE: N45.2.12 Work Group has petitioned N45. 2.10 Work Group to 11 change the definitions as indicated above.

12 -

13 1.5 Referenced Documents. Documents that are required to be included as a 14 part of this' standard are identified at the point of reference and described 15 in Section 6 of this standard. The issue or edition of the referenced docu.

16 ment that is require ( will be specified either at the point of reference or in 17 Section 6 of this standard unless otherwise specified in the contract document.

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\"J 19 2. PERSONNEL

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21 2.1 General. The responsible auditing organization shall select and assign 22 qualified auditors who are independent of 'any direct responsibility for per.

23 formance of the activities which they will audit.

24 In the case of internal audits, the persons having direct responsibility for 25 performance of the activities being audited shall not be involved in the 26 selection of the audit team. j 27 I 28 2. 2 Personne1 Qualification. The responsible auditing organization shall establish 29 the audit personnel qualifications and the requirements for the use of technt.

30 cal specialists to accompitsh the auditing of the Quality Assu.rance quality 31 sssurance programs. Personnel shall be selected for Quality. A -----

32 quality assurance auditing assignments based on experience or training which 33 establish that their qualifications are commensurate with the complexity or s

.P 11 raft 3. Rev, 4 FREEDOM OF If60RMATION ACT REQUEST S Y -4sf c./7:3 . . .. . . . .

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I 2.4.2 Review and study of codes, standards, procedures. Instructions, 2 and other documents related to Quall.ty Assu.rance quality assurance

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.3 programs and program auditing.

4 5 , 2.4.3 Participation in training or orientation programs as described in Section 2. 3.

6 7 -

8 3. AUDIT SYSTEM 9 3.1 General. This section establishes requirements for a comprehensive audit

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10 system which shall be planned, documented,' and implemented to verify _ k 11 compliance with the elements of a quality assurance program. The audit 12 system shall be described in approved, written policies, plans, procedures, 13 instructions, or such other documents as appropriate.

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14 The. objectives of the audit system pe, storming. audits.et the. quality assusance.psogr.am are:

15 16 3.1.1' To determine that a quality assurance program has been developed 17 and documented in accordance with specified requirements; y,18 \ 3.1.2 To verify by examination and evaluation of objective evidence that

19 the' documented program has been implemented:

20 3.1. 3 To assess the effectiveness of the quality assurance program:_

21 3.1. 4 To identify program nonconformances; and 22 3.1. 5 To verify correction of identified nonconformances.

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'24 3.2 Essential Elements of the Audit System. An effective audit system shall be 25 established and maintained and shall include the following essential elements:

26 3. 2.1 ~ A management policy statement or procedure which establishes 27 organizational Independence and authority and commits the organt.

28 sation to an audit system meeting the requirements of this standard.

. 29 3.2.2 Manpower, funding, and facilities to implement the audit system 30 os audits ,

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(:/ .5- . r-kruary 22, 1974 i

FREEDOM OF INFORM T10N "

ACT REQUEST

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1 3.4.2 Audits shall be regularly scheduled on the basis of the l 2 status and importance of the activities to assure the ade-  !

"' ? quacy of, and conformance with, the program. Applicable

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4 elements of the QualLty Assurar.ca. quality assurance prograrn 5 shall be audited at least annually or at least once within the 6 life of the activity, whichever is shorter.

7 3.4.3 Regularly scheduled audits should e supplemented by audits 8

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t conducted of one or more of t e following conditions:  ;

9 3.4. 3.1 When it is neces sary to determine the capability 10 of a contractor's Quality Assuzance quality assur.

11 ance program prior to awarding of a contract or 12 purchase order.

13 3. 4. 3. 2 When, after award of a contract, sufficient time has 14 elapsed for implementing the Quall.ty Assurar.ca 15 quality assurance program and It is appropriate to 16 determine that the organization is adequately per.

17 forming the functions as defined in the Qua1Lty Assur.

y ,. . . 3 W 18 ' ance quality assurance program description, codes, 19 standards, and other contract documents.

20 3.4. 3.3 When significant changes are made in functional 21 areas of the Quality.# --"- u+ quality assurance 22 prograrn such as significant reorganization or pro-23 cedure revisions.

24 3.4. 3. 4 When it is sus pected that the quality of the item is 25 in jeopardy due to nonconformances In the Quality 26 Assurance quality assurance program.

l 27 3.4. 3.5 When a systematic, independent assessment of 28 -

program effectiveness is considered necessary.

29 3. 4. 3. 6 When it is necessary to verify implementation of

30 required corrective actions.

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1-4.2.4 Audit Notification. Involvad organizations shall be notified of a ,

2

. t scheduled audit a reasonable time before the audit is to be performed. i

)D This notification should be in writing and include g-~1 such infor.

4 mation on as the scope and schedule 'of the audit vwie of. meetings 5

and. method.of audit. and the name of the audit team leader. Un.

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announced audits may be performed with prior agreement of the 7 parties involved.

8 9 4. 3 Performanca..

10 4.3.1 Pre audit Conference. A brief pre-audit conference shall be con.

11 ducted at the audit site with cognizant organization management. The 1

12 purpose of the conference shall be to confirm the audit scope, present I

13 the audit plan, introduce auditors, meet counterparts, discuss audit i

14 sequence and plans for the post-audit conference, and establish I

.15 channels of communication. .

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17 4.3.2 Audit Process.

,.,., 18 4.3.2.1 Checklist procedures shall be used to ensure depth and

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&. continuity of audits. The audit checklist is intended for use 7 '20 as a guide and should not restrict the audit investigation 21 when findings raise further questions that are not specifi-22 cally in'cluded in the checklist.

23 4.3.2.2 Objective evidence shall be examined for compliance with 24 quality assurance program requirements.

25 4.3.2.3 Selected elements of the quality assurance program shall' 26 be audited to the depth necessary to determine whether or 27 not they are being implemented effectively.

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28 4.3.2.4 When a nonconformance is Mentified as a result of an audit.

29 further investigation shall be condpcted by the audited 30 organization in an effort to identify the cause and effect of 31 the nonconformance and to determine the extent of the 32 corrective action required.

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, . . . . 'a I thirty days after the audit.

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3 4. 5 Followup.

4 4.5.1 By Audited Organization. Management of the audited organization 5 or activity shall review and investigate the. any adverse audit 6

findings to determine and schedule appropriate corrective action 7

including action to prevent recurrence and shall respond to the 8

. report in writing within thirty days after receipt, giving results '

9 of the review and investigation. The response shall clearly state 10 the corrective action taken to prevent recurrence. In the event that 11 corrective action cannot be completed within thirty days, the audited 12 organization reply shall include a scheduled date for the corrective 4

13 action. The audited organization shall provide a followup report 14 stating the corrective action taken and the date corrective action 15 was completed. They shall also take appropriate action to assure 16 that corrective action is accomplished as scheduled-

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,.p 4.5.2 By Auditing Organization. Followup action shall be performed by the QB audit team leader or management of the auditing organization to:

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19 4.5.2.1 Asswe tha.t. Obtain the written reply to the audit report.  :

20 la.. received

21 4.5.2.2 Evaluate the adequacy of the response.

22 4.5.2.3 Assure that corrective action is identified and scheduled 23 for each nonconformance. '

24 4.5.2.4 Confirm that corrective action is accomplished.as 25 '

s cheduled.

26 Followup action may be accomplished through written communicangn,_

, 27 reaudit, or other appropriate means.

g -A 29 5. RECORDS 3 30 5.1 General. Records shall be retained by the auditing organizations responsible 31 for activities associated with Impicmentation of this standard. The,se records 32 shall be collected, stored, and maintained in accordance with American

]3 National Standard N45. 2. 9.

PhEEDOM OF INFORMAtlON r .

ACi REQUEST W -tLf!"

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pate: Oc t obe r 30, 1980 Address Writer care of:

United Engineers & Constivet ors lec.

To: William C. Black 30 South 17th Street Chairman - Working Croup philadelphia, Tenna. 19101 -

Phone No. (215) 422-3934

      • #*#* AII*"

Committee: 359 Technical Committee on Concrete Pressure Components for Nuclear Service ^* * **""#

Working Croup on Reinforcing and Prestressing Systems

Subject:

Testing Frequency of Rebar Splices The 1980 edition of the code, Article CC-4000, sub-subparagraph CC-4333.5.2 and CC-4333.5.3 define the splice samples and the frequency of samples to be taken for tensile testing. If more than one splicing crew is,sorking on the job, it is possib.le, that always the same splicing crew's work will be sampled and the other crew's work'is not sam' pled, because of lack of instruction in the code.

I propose to submit a code change by the working group to assure the even sampling of each splicing crew by code requirement. .

The sub-subparagraph CC-4333.5.2 should read:

a CC-4333.5.2 Splice Samples. Samples shall be taken randomly representing all

. 5plicing crew's work. Splice samples may be production splices (cut directly from in-pl.=ce reinforcement) or sister splices (removable splices made in place next to production sp.lices and under the same conditions), in accordance with the schedule established in CC-4333.5.3.

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. FREEDOM OF INFORMAll0N ACI REQUEST 34-VTf c.,hst

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ACI-ASME WORKING GROUP ON REINFORCING AND.PRESTRESSING SYSTEMS Meeting in New York City. ' June 17. 1981 ,

Meeting was called to order at 8':30 AM. Attached is the record of attendance. The agenda sent to members under letter of June 3rd was used and the following actions taken: ,

JC 9-40 (MCE 79-7) -

CC 3000/4000 Rebar Tolerances.

This item had previously been approved by the Working Group with changes as covered in letter of December 2,1980. Black to Allen. No further action required by Working Group.

JC 9-75 (MCE 78-48) -

CB/CC 2442.3.2 Corrosion Preventive Coatings.

This item previously approved by Working Group. Had been rejected by ACI Standards Board and returned to ACI-TAC. Will be acted on by TAC shortly. No further action required by Working Group.

JC 0-20 (MCE 80-16) - CB/CC 4432.5 Twisting and Coiling Tendons.

-This item previously passed by Working Group. No further action required by Working Group.

JC 0-64 (MCE 80-41) -

CB/CC 4323 and CB/CC 5340 Rebar Bending and Examina-tion of Bends.

This item had previously passed Working Group.

Discussion at this meeting resulted in recomendation for editorial " improvement." vis; CB-5340 proposed revision, last line, change "of" to "for".

MCE 80-25 -

General Requirements for Materials.

No action required by Working Group.

MCE 80-53 -

CC-4333.5.2 Splice Sample Frequency. ,

The Working Group reviewed this internal proposal and detemined that currently the Code requires 100%

visual inspection, all splicers prequalified.

< specified number of splices tested. The NRC Regulatory

< Guide specifies splicing crew as a variable. After much discussion a motion was made by Moore, seconded by Barry that proposal to revise Code be rejected.

The vote was 6 yes. O no. 10 members. It was subse-quently commented that requirements for crew identifica-

- ' tion can be handled on a job basis.

FREEDOW OF INFORMATlON -

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COMMITTEE CORRESPONDENCE SOCIETY / COMMITTEE: ADDRESS CORRESPONDENCE TO:

ASME/ACI-359 R. E. Lipinski Structural Engineering Branch P-1022

SUBJECT:

U.S. NUCLEAR REGULATORY COMMISSION Reinforcing Steel Splice Sampling WASHINGTON, D.C. 20555 ,

MCE 80-53 A EN ^

NO. DA'TE: 00T19iM TO: James Allen, Chairman Joint Committee ASME/ACI-359

Dear Mr. Allen:

I am sending this letter to you in view of Bill Black's resignation from his Chainnanship of the WG on Reinforcing and Prestressing Systems. I wish to comment on the decision of the Working Group regarding Item MCE 80-53, CC-4333.5.2, Splice Sample Frecuency, which was voted upon during the meeting in New York City on June 17, 1981. The issue was brought up by A. Valentenyi through his letter to W. Black dated October 30, 1980 in which he proposed a code change to assure the even sampling of each splicing crew.

The minutes to the meeting indicate that the proposal to revise the code was rejected.

It is my opinion that the recomendation of Mr. Valentenyi would contribute to improvement of quality control in concrete construction of safety related structures without undue hardship to meet the requirements of the code. The reasons for this are as follows:

1. A " splicing crew" is usually comprised of a certified operator (cadwelder) and one or two iron worker helpers to assist in preparation for splicing (i .e. , cleaning, lifting, etc.). The individual operator provides direct supervision of each step in the splicing process and is assigned a unique identification symbol which is applied to the completed splice for traceability during inspection and testing. The entire splicing crew need not be identified, only the qualified splice operator.
2. I recommend that the intended sample frequency include the operator variable since reinforcing steel splicing (cadwelding) is highly operator dependent and should include test samples for each operator in order to identify substandard operator performance.

FREEDOW OF MRMATON ACT REQUEST S4-Mr me ,o /

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James Allen, Chairman 3. Although I can appreciate the WG's concern with regard to accounting problems, it is my understanding that in the past compliance with the sampling requirements of Regulatory Guide 1.10 and ANSI N45.2.5 (1974) which required separate test cycles for mechanical splices based on position, bar size for each splicing crew did not present undue difficulties.

I hope that the above will be taken into consideration by the WG at the next meeting and that the vote will be reversed.

Sincerely, L a s.tAf +'

Romuald E. Lipinski, Member Working Group on Reinforcing and Prestressing Systems cc: R. Vollmer W. Morrison J. Knight

. F. Schauer

  • G. Arndt R. Shewmaker R. Rohrbacker F. Rinaldi FREEDOM OF INFORMAIl0N -

ACT REQUESI 84 -WC c/786 L

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