ML20094J322

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Testimony of H Singh Re Origin Remedial Measures Proposed by Applicant for Auxiliary Bldg & Corps of Engineers Evaluation of Remedial Measures
ML20094J322
Person / Time
Site: Midland
Issue date: 11/12/1981
From: Singh H
NRC
To:
Shared Package
ML19258A087 List: ... further results
References
CON-BX16-038B, CON-BX16-38B, FOIA-84-96 NUDOCS 8408140286
Download: ML20094J322 (5)
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{{#Wiki_filter:g m,w2asn a mbe m l e, Tdbmcq ch NM Redd 4t\\b1 C W -c o p.r, y 41.18 tat remedial measures did the applicant propose for the Auxiliary Building? I The oria61 remedial asesures proposed by the applicant 7 l A. (a) orted la Istaris Report 6, June 11,1979, itAR 24,10CFR 50.55(e). It consisted; (1) Pressure groutlag to fill the void (see item 3) under the andant of the Centrol 1 faser: (2) removing mesmitable beckfill esterials from bee **th the Electrical Penetration Arees (EFA) and the Feeduster Isolation Valve Fits (PUIVP), and j replacing them with lean comerate with compressive strength of 2000 1he per h square lach. 1 j (b) On 18 July, 1979, la a meeting with IRC officials la Betheade,18, the applicant presamted a ese plan for tlur remedial measures for the Electrical Pene-tration Arees. The new plan eslied for providias emissoes se the autremeties of hoth the Electrical Femetration Areas. with the celesees' empports at the ende, j the EPA's would met as propod sent11evere se either side of the Control Tower, relieving the fill meteriale under the spa's from the pressure created by the structure leads, and tremonittles them to the competent natural soils through the ceasemen and to the foundettee of the Centrol Tower. The remedial measures for the Fheemster Isolatten valve pits r==mtama aams as original. (c) en 5 Ney 1981, le its meeting with NRC the appliomet presented meether remedial settom plan for the Electrieel Penetration Areas. This plan comeisted cf providing solid concrete empport feetoed of the caissoas se mentioned is para-sreph (b) at the estroomties of both the EPA's, and also to estead the solid com-erste support under the meerby Tearhine Smilding te spread the structure loads on i larger femadaties acues se keep the famedettom pressure under permissible limits. (d) on 1 October, 1981, in its meeting with the NRC and the Corps of Engineers offleisle, the applieset pressated a plan for the remedial measures for the Auxiliary - Sailding (EPA's med Fv1Vp's) which use different free the ones mentioned is para-sreph (a). (b) and (e). This plan, the meet resset one, calle for providies (1) eentieseems maderpinelag well restieg om undietrashed esteral meterial, isoder the esternal wolls of the Electrical penetration Areas, the Control Tower, and the poedwater Isolation Valve pates (2) three imelated sospports to the Control Tower-along a emet-west line through the senter of structure and parallel to its mouth enternal crees enllas and (3) underpinning well supports to the enternal eroes wella of the Centrol Tower, and mise see intermediate eroes well support to each j epa. Atteelement shows rJee detalle of this remedial measures. Q.2. Did Corpe of Engineers evolusta verleue remedial measures n g :::f by the appitcast, if yes, thee uhat were the results of its reviewet i A. 1he Corps of Engineers entered me 1staragency agreement with NRC im September i 1979, to moetet the Mac im evalesettes the goetechnical aspects of the Midland } Wuelear Feuer Fleet. The remedial action for the Aue111ery Buildies under com-ciderettee of that time sea to provide caiseen supports at the extremittee of the Electrical penetraties Areas (see peregraph b, questice No. ). Therefore. Corps did seet evelante the original remedial messenree proposed by the applicant om 11 June 1979. The renaisies three proposals have been evaluated by the Corps of i !i Em5 meers, sed the followies are the review comments: i 8408140286 840718 PDR F01A RICE 84-96 PDR MM(ty7 A"#' 7 "WT ~ /. racsoneta maases sneat W Wo2(.. 1 %, M * * / s,_ _ r._ -. ._ qKR IM-c.. $ r _,__,, _ _ kAO y 2-y?M l .. m jl A- -#,. L. "* MF " y,- - - -. - - - -. _., -. m .. ~.. -.. - - - -. ,, u.s.a e + -w ^- ~

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. g,.p7 '; f l %.1, a n,>. v.=e' ... q ;. _ s n Q r 6 i _ t; i V 0 2 (a) namedial action with catason supports (proposed on 18 July 1979): (1) This proposal had effects of transforetag the continuously soil j mupported spa structures into propped esatilever structures, fixed with the Contro1 j .j Tower at one end and supported on caiaeons on the other end. Consequently, approx-instoly half of the gPA's loads (approximately 9000 kips) was going to be transferred M on the Control Tower increasing the foundation pressure on the compacted fill sup-poreing ahe otruesure resulting la additsamat setelements. M (ii) The design inforestion about caissome: The capacity of each j ocicson to earry vertical and lateral toede, the capacity of caissons me a group q j (croup offects), settlements of caissons' group, negative skin friction on the O coissons due to future settlements of the fill meterials in which caissons were to be installed, the hearing capacity and the factor of safety meninst ahear il folitre of the meals supporting the caissons were not furnished. The Corps of ll gnaineers, la paragraph d(e) of Page 6 of its letter report of 7 July,1980

i requested the applicant to furaleh this information.

The applicant response ,j ' provided through Admondment SS was not satisfactory. The Corps' report of 4 J! U 10 May 1988 (See Q. 42, Page 7) provides the reasons. 'l (iii) The soil parameters (shear strength parameters of fill materials and clacial till) controlling the design of caissons were not furnished. The Carpe i of gngianere esquested the applicant through Nec to perform soll exploration testing os representative soil samples to obtain sheer strength parameters. (b) Ramedial measures with solid concrete support at the extreattles of the

gFA'o (proposed om 5 May 1981)

c The applicant has not furnished any design information regarding this [ j ccheme after its brief verbal presentation of the scheme on 5 May 1981, in a meeting with NAC. In Bethesda, MD. Therefore, there were no information available to eval-

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i unto the adequacy of the scheme. 4 i y j (c) Remedial measures with underpinning walls (proposed on 1 october 1981): t This in the currently propos,sd remedial momeures. A detailed evaluation j cf this sehene has been made in queaeion - 3. a v Q.3. Did you evaluate the currently proposed remedial moseures for the Auxiliary Building, if yes, then what are the reagita of your evaluation't ! A. The remedial measures currently under consideration to stabilise the portions 3 ef the Auxiliary Buildtas (EPA's, FW1VP's and Control Tower) has been described 1 in P.:ragraph (d) of answer to question No. 1. The Corps of gngineers has reviewed j the cpp11 cent's technical report and associated appendices (Attachment No.....) ]whichincindethedesigndetails. The results of the review are as follows: c. Bearing sepscity of underpinning wa11a I{ (1) The bearing espacity analysis using an average of undrained shear , percngth of 6.6 kaf is not appropriate. While it provides a conservative design l [er the underpinnias wells which are adjacent to Boring No COE-18, (samples from 3 fog-Isshowsahearstrengthmorethan6.6kaf),itoverestimatesthebearing i l

apacity of the foundation soils supporting the underpinning walls adjacent to kl 2-

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^ __=_n . - s.:.. - - -sm 1 L sortog Me. CUS-17, elece the mail emeples freen these berings, taken from the L potential some of lefluence under the footings of underpiseleg wells, have indi-eased sheer stremsth auch less then 4.6 hof (ehear strength of S.t$ kaf and less). Therefore, it to advisable to proporttee the foundatiase width of the underpinning wella adjaeont to C05-17 ose the beets of sheer strength obtained from teste on samples free C03-17. (11) The eetual factor of safety aSaiset the shear failure of foundation seile under the dysente lead for various underplening walls have not been furnished. i (iii) The bearing capecity analysis med the reeutting factor of safety ( weder dralmed esedirlos have not boom formiehed. The consolidated andraised tests have steoem that true eehmeten of the foundation soils are much less them the { apparent eeheeles shown by undrateed tests. Therefore. it is advisable to verify the citimate bearing empeeity em the beste of drained test results. a ( x b. Settlenester (1) The settlements for the proposed underpinning walla provided on pose 9 of ther techsteal report have not been demonstrated to be justified by the appifeset. The total settieneet of foundation solle casestitute three parts: (1) imandlate settlemoet et eoestant volume, (2) consolidation settlement due to cheaew 1e oo11 volume emissed by espeloton of emcess pore water, med (3) ser t y settle-esma. For hiehty souvesseo11 dated sell where settlement le primarily the results -a l cf reeempressima, the me&& tieeld behave elastically and it seuld be reasonable to Compute settleemets mains the Young's sedulum of the soil. However, such settle-seat computetten does set faciude the seemedary settlement. therefore, secondary i settlements should be computed separately esing coeffieleet of mesondary consoli-i l dettoe and be added to ahe inumadiate settlamest. The cpptiemet's computatioses for settleomente appear to be based on the assumptions

hat seil is highly everconsolidated, and slee settlements will he the results of recompressies of foundatise sella.

10ewever, the applicent has not computed and presented the preseemetidettee preceares for the foundation soil to documestrate that the foundettee seils are overcosse11 dated. Therefore, whether the elastle appreesh used by the app 11cass to campete settleesets le applicable or not is noe kneese. ~ (11) Nothods of computing secondary settleneste are not presented in the report. It is our understandles the the opplicant has used coefficients of secondary , consolidation. . determissed by the consolidation tests to determine the secondary settleanset. Bowever, as mentioned earlier le aneuer to Qesestion.... elece 4 results of consolidation tests are aquestionable. the determined free consolidation testo are set appropriate for eseputies secondary censolidatiese. (111) Settlement eenitoring dutieg sometructions t The applicast's program to teamte stahality of the esisties structures, (EPA's and contes 1 Tower) deertog the perled when eene of the sette underlying their foundatione

call be removed to eaka rose for construction of underpinning mello, commists of moottcries the settlemente of the structures at critical points.

The applicast's i monitoring program presented in its techalsal report has been reviewed by the Corps cf angleeers sed the NRC med their review commerete were transmitted to the applienat on 30 October, 1981 threech a telepheme conferasee (Attachneet.... ). i l ~CK - = . - - _ _xa;.a:...}i:w,, =a M'*V.WQ'TT..:f;,.x.: wa.J ~ x y = =.-.

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  • l Q.4 Did you review the lepodward-Clyde consultants' report which included the results of soil emploration and testings of samples taken from the area of the Auxiliary Building?

If yes, then what information was included in the report, and what are the review casaments? U Ana. m. The volume 1 of the Woodward-Clyde report concerning the Auxiliary I Building was received in last week of September 1981. The report contalma the fellowing Laformations (1) noting los information for Boring No. Cos-17 and Cos-18. (2) Results of gradation tests of soils froin these borings. t y } G (3) Results of unecesolidated undratmed (UU) tests. (4) amoults of conso11 dated undrained (clu) tests. l (5) Results of consolidation tests. (6) Esekup meterials for UU tests. (7) Backup meterials for CIU tests. (8) Backup meterials for consolidattom tests. b. The results of the UU tests os repreyntative mail samplSe taken from the potential some of influence (between 35-550 and 570) of the usaderpientes wall foundations, indiente that soils of Bories No. Cos-17 have lower shear strength them those of Boring No. C0s-18. Therefore. it will be appropriate to proportion the foundation for the underplanlag min 11s for Unit - 1 sFA and FWIVP, which are c1:eer to Cos-17, unies they ower shear valve from Cos-17. However, the lowest che:r strength valve of 2.M kaf obtained from semple no. hah $ is not correet; l the Corps of Engineers cosecurs with the Woodward-Clyde remark that the low shear cerengt.h is the result of semple disturbance. This valve should be disregarded. c. The drained ahear strength parameters (true cohesion C and 3) obtained from the Clu tests indicate that shear strensth of soils, at normal strees at potent,lat failure plane, is lower than their undrained shear strength (su = 5 18 k:f and more), therefore, in our opinion the bearing capacity of foundation soils chould be checked using drained shear strength. d. Preconsolidation preneures and the over consolidation ratio for the solls in the mone of influence of the underpinning walls have not been determined. There-fero, use of the elastic approach to soupute the settlemente, which is appitcamle la the cases where soil is highly over consolidated and the settlement would be the result.m of recompression, has not been resolved. No volume p ree during UU tc to and development of sero W to slight negative value for,,) ort pressure parameter, A, at failure loads, indleates fadirectly that the soil le moderately over eemoolidated, however, their def faite valtwo are not known. -l e. The e-los y eurves for the coneotidaties tests indieste that the amen-1 dations of consolidation samples were done at 21 taf strges. This appears to have conalderably influenca consolidation tests +.pIccording to the Corps of EngineerAlgg,9W of e-log y curves and duch the re manual DI 1110-2-1906, i PCse VIII-8, the specimen should be inundated immediately af ter applying first l load inernment of.25 tef. If swelling securs apply additional Inad h---- O /ko. N O 77~ l until swelling saanes. 4 0 g/ 7 t/42 Y%2Gs / ? ,~,,. 'u "c"**N,M" **"' DC L&exs 2 W2-Y9}Y ~,.. m.. m

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-Sw J On 4 November, 1931, la a meeting with NRC and Corps officiale, the applicant clarified some of the diseropensies, heuever, probably due to lack of time, the applicant wee not ready to respond some of the questions which are critical to the eefety of the structure durlag the construstles of the underplanlag wolle. Thercfore, the staff could not reach en egreement with the applicant on the ~. '; " y of its settlement moottering program. The me plicant roepease to question No, 9, 15, 18, 20, 23, 24, 25, 27, 23, 29 and 30 of Attachment No. $.... and Choir evolustien by the Carpe are necessery before providtag its concurrence to the propeeed settlement monitoring program. i (iv) Emme-term difforesttal seatieneste f Nest of the eenpeted settlement under the underplungin wolle would occur prior to the permanently transfer of the structure leads on the underpinning well. Neverthe - ICO2, because of secondary settlement and part of primary settleeset the structures (epa's and Coetrol Tower) would undergo sees differential settlemente creetlag some additional stresses in the structure. The applicaat meet evaluate these difforential settlemente and effects eush settlement se the structure. In Qneestion 14 of Attach = meet - 1 Corps of Engineers has requested the applicant to establish the soil sprime eenstant which would help evaluate the stresses due to dif forential settle-most7 Comblastonea a. The overall concept of the corrently pr;;;d remedial measures appears to be estisfactory. The reendial measures if built gettefactorily, uom1d trame-Cit the structure loods estasseseaweep to the campetent soil layers, relieving the fill meterials from any esternal lead. It will also eliminate the problem of everctreceing the foundation seile of the Control Tower, whleh wee taevitable with the previously proposed estemosesupport. Neuuver, a proper foundettom design bemed on accust soll parameters, se mentioned in portices of peregraph a(1), le essential and the Corpe of magineers weeld like to review the final design before givins ite' _ ~ concurrence. b. Evatustice of long-ters dif ferentisi settlements beoed om eiestic theory using Young's modulus of the sette le applicable to highly over consolidated soils. The appiteent has not yet demometrated that seile under the underpinains welle are preconsolidated suf ficient enough that settlemente produced by the lead imposed on ' the underpioning walle will be the results of rescupression only, and therefore. the use of elsetic theory to justified. F%srther, the Young's sedulus of solle to be used in settlement analyste eheutd be determined freus a stress-strain curved ohtcined irom drained toeg e. Although, the magnitudes and the methods of computing secondary settlements wars dieeussed in 4 November,1931, meeting in Bethesda, they have not been doeu-mented in the techeleel report. It le advisable to docuanent the analysee faciuding values of " 4", stresses and thiekness of compressible meterial considered in the cnalysis. d. Monitoring of settlements of the structures to be underpinned, sad deter-mination of acceptance eriterie for settlemente, during the construction are of paranomat importance for preserving the structural integrity of the gPA's and Control Tower. Therefore, resolution of questione raised by the Corpo and NRC ctcf f res.rding.o.itori.g,rogr. i. esse.ti.1. 6 ,7.ggmypy gy _:.n . -.. cam a.c;_ u;_ . m. %mga a

f ). & k umTEo STATES y (( NUCLEAR REGULATORY COMMISSION j j wasmaeron.o. c.2ases e W(N 2 31981 2 Docket Nos. 50-329 OM, OL and 50-330 OM, OL APPLICANT: Consumers Power Company FACILITY: Midland Plant, Units 1 & 2 ~

SUBJECT:

SUSARY OF NOVEM ER 12, 1981 MEETING ON CONSTRUCTION SCHEDULES FOR FOUNDATION MODIFICATIONS TO AUXILIARY BUILDING On Noverrber 12, 1981, the NRC staff met in Bethesda, 2, with Consumers Power Company (CPCo) to discuss construction schedules needed for the planned H remedial actions to the Auxiliary Building at the Midland plant. The remedial action, underpinning, results from the settlement potential of the backfill soils beneath the control tower and electrical penetrations area of that structure. Similar action is planned for the adjacent Feedwater Isolation l! Valve Pits and was included in the meeting discussions. Meeting attendees l are listed in Enclosure 1. i Vice President J. Cook of CPCo reviewed the development history for the proposed l remedial action whit.h had initially been based upon use of jacking caissons, but which by September 1981, had been changed to a structural wall extending i to the glacial till.. Mr. Cook emphasized. that the construction schedule for I the Auxiliary Building underpinning was critical to the July 1983 fuel load /, i date for Unit 2. For this reason, Consumers had earlier asked the Licensing I Board to rearrange the hearing sessions to consider the Auxiliary Building before the Olesel Generator Building session. To prepare for implementing the under-pinning, a vertical access shaft on the east and west ends of the auxiliary building and adjacent to each feedwater isolation valve pit and the turbine building needs to be started by mid-December 1981, and a freezewall by-December 29, 1981. Staff approval of these two matters were requested by Mr. Cook's letter of October 28, 1981. The schedule for start of drifting beneath the structures is February 15, 1982. Mr. Cook further emphasized that L continuing staff review throughout the underpinning process was needed, rather s than a traditional two-step staff approval process. He felt that more staff 4 ,I review and observation in tne field should be considered to expedite the review l. process. Review procedures such as that which had been followed during the staff's structural design audit at Anne, Arbor, Michigan, in May 20 - 24, 1981, were also recomended. neede. h'eco ruc 10 sche u e h suggested specific approval. Points by the staff or other conditions be defined based upon the planned construction activiti d b c mprising the underpinning scheme. He noted that establishment of a ditions could assist in the authorization to proceed. It was agreed that orfin eeting the following week would be scheduled to this end. To the extent possible, such conditions would be reflected in hearing testimony. '05 I vg.

--e g-g i %s 1 tr .- H Moeting Sunuary. Midland, Units 1 & 2 Mr. M. Miller. Esq., noted that conditions could not be established within the j existing schedule for filing testimony (due November 17, 1981) and that 1 Consumers would like to ask the Board to accept a delay of a few days in the filing date. Mr. W. 01sstead. Esq.. replied that the staff would not object to such a request. j Messrs. G. Keeley and D. Budzik of CPCo described the preliminary analysis of the Auxiliary Building to be provided for staff review on November 20. 1981. The i preliminary analysis will consider selected critical structural members and selected loading con 61 nations. An analysis of the construction sequence for the underpinning scheme will be completed January 1,1982. The final analysis will be .,j provided for staff ruview February 15,1982. It was noted that the latter date l corresponds to the start of drifting beneath the structure. The final analysis is primarily for the electrical penetration area and control tower portions of the s tructure. The analyses for the overall structure will be completed April 15 1982. June 1.1982 is the earlist date that the FSAR can be updated to reflect .y;l the results of the completed analy:es. ~ 'i I At the conclusion of the meeting, and in preparation of the working session planned for Novenbar 17, 1981 Mr. BuHzik provided the following schedule j drawings to the staff's project manager: i [ (1) Drawing 7220-PPS-020. Revision 0, dated 11/06/81 " Project Production Schedule: Auxiliary Building Underpinning Schedule", sheets 1 and 2. l (2) Drawing 7220-PPS-021. Revision 0, dated 11/06/81. " Service Water Pump Structure Remedial Action - (Underpinning Wall)". 4 'l .I Darl Hood. Project Manager i _ Licensing Branch #4 ~ Division of 1.icensing ^

Enclosure:

As stated cc: See next page b a / .. -.,.a.am.m..1aug.....ca.: sua==e >.Sicod:.1h -... DEkinSusa.....EA e yam....... om>....l.lli?l.al...........).11.p/la1.....l.1.l.g.. /.8,1,,,,,, aac roau sie gio.aomeu aaw OFFIClAL RECORD COPY g ~.. - usa m ini am.

1 . u.- v r.. ENCLOSURE , - ""I 1 . -s LIST OF ATTENDEES MIDLAND MEETING 11/12/81 j NRC -~ I D. Eisenhut J. Kane R. Vollmer F. Rinaldi J. P. Knight A. Cappucci E. Adensam G. Lear l W. Olmstead F. Schauer J. Rutburg R. Landsman W. Paton D. Hood i I consumers J. Cook . D. Keeley D. Budzik M. Miller (IL&B) 1 t ) i t '4 E v ' e F 5 t ww - s e.ow w~- o.--,, n,n_,_._ _,,,., +,,,,. _. --.

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  • ese

/ ,e J.1 MIDLAND PROJEC2 - \\ ~' DOCE2r NCS 50-329, 50-330 s AUIILIARY BUIL' DING SEISMIC ANALYSIS a -{ FILE: 0.h.9.h8 UFI ' T3*10*01, 70*0l* n*03, h5*05'20 SERIAL: 12008 'f

Reference:

CPCo letters to J G Keppler, Same

Subject:

f

1) ' Serial No 11200, dated February 20, 1981
2) Serial No 11972, datei April 16, 1981

.I This letter, as were the referenced letters, is an interim 50.55(e) report concerning the anv414=7 buf1d47 seismic analysis. Attachment 1 provides !j a status of the planned l corrective actions. 'I } i Another report, either interim or final, vill be sent on or before ,8 July 31, 1981. }, / j WRB/1r Attse'2mant 1: MCAR-47, Interim Report No 3, dated May 15, 1981 "Anv41f= 7 Building Seismic Analysis" .i CC: Director--of Offir e of Inspection & Enforcement Att.Mr Victor Stello USIRC (15) Director, Office of Management Infomation & Program Coctrol, US3RC (1) RJCook, USNRC Resident Inspector Midland Nuclear Plant (1) i. Golf l I _s2!_;5,o.s e b kl 1 gpp. o. .. --=-L-

sx ;,..; ;..~ __ _ _- - = -_ 1 as. t', 2 Serial 12008 81-02 #3 CC: C3echhoefer, ASLB Par.el RSDecker, ASLB Panel FPCowan, ASLB Panel AS&L Appeal Panel 14 Cherry, Esq MSinclair CRStephens, USERC

  • "DPaton, Esq US3RC

= FJKelly, Est, Attorney General SHFreeman, Esq, Asat Attorney General GTTaylor, Esq, Asst Attorney General l WHMarshall e GJNorritt, Esq, T3KkT 1 1

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_=~~ - =~ ~ - y,w t.._ :. .s - _-...: J. s 1 3 Serial 12008 81-02 #3 CC: C3echhoefer ASL3 Panel asm.nir.r. ASL3 Panel PPCowan, ASL3 Panel l ASE Appeal Panel 4-.,'- 180 Cherry, Esq ugu, w 1 1 CBStephens, USERC 3 ~ WDPaton, Esq. US3RC nEeur. E.q, Attorner Ge.amt SEFreeman, Esq Asst Attorney General MTaylor, Esq. Asst Attorney General WIMarshall GJNerritt, Esq, T3E3J l Ei s. 6 4 i ~ e e4 - +- 6 6 J ..j:.. h t s 4 r k 0 1 4 +m-e

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e seria 12o08 Bechtel Associates Professional Corporation 81-02 #3

SUBJECT:

MCAR 47 (Issued 1/29/81) Auxiliary Building Seismic Analysis INTERIM REPotr 3 DATE: May 15, 1981 PEOJECT: Consumers Power Company a Midland Plant Units 1 and 2 Bechtel Job 7220 j Description During a seismic reanalysis associated with the 10 CFR 50.54(f) plant fill issue, it was noted that the 1977 auxiliary building seismic model considered the control tower and the main portion of the suziliary building as an integral unit between el 614' and 659'. This assumption may not be appropriate for the north-south direction because of the connection between the control tower and the main structure, which con- - - A.i sists primarily of reinforced concrete slabs. The auxiliary building and the control tower were structurally designed to a 1974 seismic model which included flexibility at the connection between the control tower and usin structure. Equipment and systems have been seismically qual-ified using output from both the 1974 and 1977 seismic models. i I Potential Safety Implications ,) 4 This ites does not have a safety impact on the stability of the auxi-liary building, equipment, structural steel superstructure, or the ,y structure of the main part of the auxiliary building. Potential safety I implications have not yet been determined for the control tower, its ~ ld connections to the aufa muwilf ary building, the electrical penetration

s.,,

.i areas, or the pipit.g systems. . +., 'l _m.,-. Investination . The_ investigation a*====d i = W ***

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~ H-- -- - determinerthe safei ". _ _.. i. <. m " Li... - T _ _ _ _ _ iL... 1,. .r-7 and the main autiliary building (el 614' to 659') were modeled as two -(. " - OM ' i separate structuree connected by a flexible link, this investigation considers possible changes in the building forces and floor response ' spectra curves. The structural behavior in the eastmsest and vertics1 --directions would not be affected by this change in the model. 'I The investigation presented herein does not include the model modifi-cation in process to resolve analysis necessary for the 10 FCE 50.54(f) plant fill issue.- T l l' t l l 1. www w.vgue- -- .m.e we ^ T-..

w.x z wx _.ax mc =- ~ I ..~ ~. Bechtel Associates Professional Corporation NCAR 47 I=teria nepore 3 030698 May 15, 1981 Page 2 The investigation with this model considers: I 1) A response spectrum analysis to develop building responses 2) A time-history analysis to develop instructure floor response spectra at selected locationa 3) Comparison of building responses to values calculated in 1974 and 1977, and to allouable forces if necessary 4) Comparison of instructure floor response spectra to those gene-rated in 1977, at selected locations, and comparison of loads in selected piping systems and equipment systems to allowable loads if i necessary. d The current status of this investigation follows. 1) The response spectrum analysis has been completed. 2) The time-history analysis and selected instructure floor response spectra have been generated. 3) A comparison of the building forces at the base has been mode. The total building base moment and shear have increased by 2% and 1%, respectively, values that are not significant with respect to overall building stability. The greatest change in building forces was confined to the structural steel superstructure, the control tower, and the electrical penetration area at el 674'-6" and above.

  • 1 The moment sad shear in the control tower, the electrical penetra-

~' tion area, and the slabs connecting the control tower to the main auxiliary building are under investigation. By inspection, the forces in the other portions of the building are acceptable.

4) - A-compariace-of-the-instzusture eoopease-eyeesee-oneves '---- M r ^

- - ~ ~ ~ ~ ~ ande and*tadttstes%t u -a difi ^ I - ^^r-~= ~ have little or no change. The greatest changes were confined to the structural steel superstructuce, control tower, and electrical penetration areas at el 674'-6* and above. The frequencies most 1 affected by this change were between 4 and 10 cpe. The anzimum increase in acceleration occurred at approximately 6 eps and was 1.6 times the previous spectrum value. In other areas in the building, the new instructure response spectra did not differ significantly from the existing spectra. By inspection, these ~ areas are acceptable. With one exception, piping systems in the area affected were found to be acceptable. The piping systems that were selected for avslua-tion were located in the area where the greatest change in seismie loads occurred and where the pipe or hanger stresses were close to s'" 4* l J !.(n ~ ~^ ~ m _=,

u __ ~ m.m. m _ _m. ._1 A Bechtel Associates Professional Corporation s y f MCAR 47 i.i s 0 u s-e.o Interia Report 3 ~ May 15, 1981 Page 3 the =arimum allouable before checking the new seismic stresses. 'i The auxiliary steam and turbine tahaust vent stack to the atmos-i. phere is the only system found that will experience substantial increases in loadings. The three supports for the vent stack will need to be checked for an increase in seismic loads. The potential safety impact of the increased load on the hangers has not been ^ ' ' determined. Equipment systems in the area affected were found to be acceptable. Equipment was selected to be checked based on its potential for change. The revised spectra were campared to the spectra used to seismically qualify the equipment, and the equipment still met acceptance criteria. Corrective Actions Completed 1) During the week ending January 23, 1981, the ar suption that the control tower and the main portion of the aux 111ary building is a nonintegral unit between el 614' and 659' was incorporated in a '9 modified model of the auxiliary building. Accordingly, this action is complete. 2) The structural response analysis has been completed. 3) The time-history analysis and corresponding in-structure floor response spectra have been generated. 4) A sample of the existing equipment seitnic qualification records [. have been reviewed and found to be adequate for the revised spec-trua. 5) The stability of the structure is not significantly affected; therefore.--it has-been found-to be-satisfactney. :- :---- - - - - - - '67 The 4trucifural 1stwar..pr= L-. hirbews'dtecked sed fbund-ttr **-" - ' ' " ' ' ~ be adequate. Corrective Actions to be Completed 1) Complete the investigation of the structural design in affected areas of the structure 2 2) A sample of the existing piping systems has been reviewed and potential safety impact en three hangers is being investigated 3) Establish whether this is " reportable" based on results of the !i investigation described above l 1 l I ~.. a n

mg m _. m z _ m _. _= l u Bechtel Associates Professional Corporation McAR 47 p Interim Report 3 030o90 May 13, 1931 Fage 4 Ecot Cause This omission, the segnitude and implications of which are still to be determined, uns not caused by a failure to follow a procMure. All procedures pertaining to the ocidination, checking, review, and approval of calculations had been follound. r' g-r y This omission involves a subjective technical determination of the most effective way to mathematically model a physical feature of the structure. The methods and values used were judged to be appropriate for the east-west direction, but detailed design review revealed that the methods and values used did not adequately represent the structure in the north-south directica. Because thise paramet'ers are specifically and uniquely determined for s 1: each portion of the structure, this omission is believed to be a random occurrence with no generic implications. Therefore, there is no generic or process corrective action p1=nnad. To support this point, models j used in the analysis of safety-related structures were visually inspec-ted, and no geometric situation was identified which would lead to a similar model omission in development of beam properties. Due to the soils problem and foundation modifications, the other models are being reviewed and will be modified if necessary. Other Activities Not Within the Scope of this MCAR .y : The scope of this MCAR, which was discussed in the preceding sections, M was to define the root cause and conduct an investigation to determine l the reportsbility of this situation. The following items are general ~ ~ 1 descriptions of activities.thar have.haan.preziously. identified..in.the.....- -p _.a Responses to NRC Requests Regarding Plant Fill. These items involve an /.., ~., i extensive rannafysis which includes changes which will correct the ^ ~ = -_ - - - - 4 --- omissiott-identifind:-in:N 1--- tracked W::that r 1 . "M _. .m w fe -thr$N!m:-_..;-_.. = 1) Continue seismic reanalysis of the auxiliary _ building considering..... _. wl4 the current building configuration (e.g., tornado shield), present ' i, ) soil conditions,-and proposed plant fill remedial action (e.g., caissons under electrical penetration areas)..This analysis will -( incorporate the modified model described in Corrective Action 3 above. 2) From Itse 1 above, develop revised seismic forces,. moments, and response spectra. i ( ?

a = ~. w: . w.:. . l ~ Bechtel Associates Professional Corporation t E MCAR 47 .1 1 l May 15, 1981 ~ 2; Inc.ri. ne, ort 3 030690 3 fi { Fase 5 a t S 3) Review existing structural designs, piping systems, anchantcal systems, control systems, and equipment qualifications for adequacy-to revised items listed in Ite. 2 above. If this action discloses discrepancies, corrective action asasures will be implemented. Y: -: 4) The affected FSAR Figure 3.10-7 has been identified as subject to channe at a later date in the Responses to NRC Requests. Eagarding f ',(.if. b Plant Fill. A.j! Reportability .-.p .] 9J@ 2..{ j This subject uns reported by Consmers Power Company to the NRC as a po-centially reportable 10 CFR 50.55(e) item on January 21, 1981. To date, Ji it has not been established whether. this item is " reportable" under the 9;6l 4 criteria of 10 CFR 50.55(e). Reportability will be addressed in subse- . ;g quant reports based on ther results contained in the section entitled utlOM " Investigation", above. 2,,~ ~ Pr6 pared by: D/ b D.T. Scribner c )^f ~ YN ? Approved by: Y i ".2 N. Sunnberg 52 ? M .,..g 4 : Concurrence by: ._ E n j. f*7 Q a 4.. kid m ,. [.f ~ .. _ _.., - ~.. -.. -~e ~_m .,I I ' $ '.66 /I.- ., y. 1. > ri ' ' rf, { i c :._ _, - t D e > 9 i 4 c, 4 O 4 _~ -_, _ _ _ h--- m-- .-C- -~- L

=- = + i . r m)DL.ASD - SE,nimC. DESnCph) unouam boa.aw&

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<i JJ f I CDilSum8IS 3 power mm Comp 311y vu, m.*., - mi,,,. e s and comer < tion } .] o.a-.s om. is4s w.= earn.n n. J =ma. m 4emot. < sin 7se oess 81-02 ~ July 31, 1981 / 1< 4, ,f-4 o e s, l' -a %, p'us 10 ggt e 1. 1 rm Mr J G Keppler, Regional Director .genAiaus v.5-ap=*# 5 '; Office of Inspection and Enforcement %'c4s \\ [ US Nuclear Regulatory Commission Region III \\ f '.t'7 ~[ [{ T99 Roosevelt Road i .) Glen Ellyn, IL 60137 ' - ~ ~ MIDLAND PROJECT - DOCKET NOS 50-329, 50-330 i' AUXILIARY BUILDING SEISMIC ANALYSIS i FILE: 0.k.9.h8 SERIAL: 12067

Reference:

CPCo letters to J G Keppler, Same

Subject:

i 8

1) Serial No 11200, dated February 20, 1981 5
2) Serial No 11972, dated April 16, 1981
3) Serial No 12008, dated May 29, 1981 The referenced letters were interim 50 55(e) reports concerning the auxiliary J

building seismic analysis. This letter is the final report. Attachment 1 provides s. numry of the actions which have been taken to resolve this ?lnal resolution will be demonstrated by the seismic analysis being concern. performed in conjunction with the 50 5h(f) concerning soils. ( ,,~ 'dRS/lr : MCAR hT, Final Report, dated July 17, 1981 " Auxiliary Building Seismic Analysis" CC: Director of Office of Inspection & Enforcement Att Mr Victor Stello, USNRC (15) S Director, Office of Management ] j Information & Program Control, USNRC (1) C d 5 RJCook, USNRC Resident Inspector f Midland Nuclear Plant (1) [g l _..- % mt0731 " @ 60CR O$000 80 s 5 W f. ' " * * * " " * * * ~ ~ * ~

f-. - L '? ~ . _ p3. 2 Serial 12067 81-02 #4 ( ' CC: CBechhoefer, ASLB Panel ESDecker, ASLB Panel FPCowan, ASLB Panel AS&L Appeal Panel MMCherry, Esq MSinclair BStam1ris CRStephens, USNRC WDPaton, Esq, USNRC FJKelly, Esq. Attorney General SHFreeman, Esq. Asst Attorney General 'whshall GJMerritt, Esq, TNKlJ s, + k i 8 I '1 O l i .m

o a ____n ^ 03f334 Bechtel Aosociates Professional t,arporation81-02 a 8*"*'l 777 East Eiesnnower Parkway Ann Arbor, Meche0sn assummonar P.O. Bos 1000. Ann Artor. Echigan 44106 SUEJicT: NCAR 47 (Issued 1/29/81) Anaxiliary Building Seismic Analysis FINAL REPORT DATE: July 17, 1981 FROJECT: Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220 Description During a seismic reenalysis associated with the 10 CFE 50.54(f) plant fill issue, it was noted that the 1977==nef tf ary bui ding seismic undel .q considered the control tower and the usin portion af the muziliary building as an integral snait between el 614' and 6'3*. This asseptfon la not appropriate for the north-south direction because of the connec-tion between the control tower and the asia structure, which consists primarily of reinforced concrate slabs. The auxiliary building and the control tower were structurally designed using input from a 1974 seismic model that_ included flexibility at the connection between the control tower and main structure. Equipment and systems have been seismically qualified using output from the 1974 or 1977 seismic undels, depending on the purchase date. Safety Implications ~ There is actually no potential safety impact on the auxiliary building and its contents because it will be modified under the 10 CF150.54(f) remedial soils action and the final design will unet acceptance criteria c prior to plant operation. The investigation described in this report was initiated solely to determine the potential safety impact on the " pre" 10 CFR 50.54(f) auxiliary building structure and did not include the structural modifications in progress to resolve the 10 CFR 50.54(f) remedial soils action. Potential safety implications on the " pre" 10 CFR 50.54(f) remedial soils action structure were determined for equipment and piping as described g in this report but were not determined for the control tower, its connee-1 tions to the main auxiliary building, or the electrical penetration areas. 2 Investination The investigation presented was limited to the north-south,1977 seismic model (FSAR Figure 3.7-10) because the structural behavior due to seismic } actions in the east-west and vertical directions is judged not to be in-fluenced by this change. The control tower and the main auxiliary I

w- ,.n,n ( Bechtel Ad$ociates Professional C~rporation ,6334 Ga MCAR 47 Final Report Page 2 building (el 614' to 659') were modeled as tuo separate structures con-nected by flexible links, this investigation considered rpsulting changes in the building forces and floor response spectra curves. h investigation consisted of: i 2 ) 1) A response spectrum analysis to develop building forces. i 4 - 1 2) A time-history analysis to develop in-structure floor 2 d response spectra at selected locations h-3) Comparison of building responses to values calculated in 1974 and 1977. 4) Comparison of instructure floor response spectra to those gene-a rated in 1977, at selected locations, and cooperison of loads in ,,j selected piping systems and equipment systems to allowahle loads if j necessary. I 'q h ' current status of this investigation follows. 1) The responsa spectrim. analysis has been completed. 2) h time-hi tory analysis and selected in-structure floor response spectra have.been generated. 3) A comparison of tue building forces has been ande. h greatest f cht ge in building forces uns confined to the structural steel superstructure, the control tower, and the electrical penetration acess at el 674'-6* and above. By inspection, the forces in the other portions of the building aset the acceptance criteria. Based on a preliminary stress analysis of the " pre" 10 CFR 50.54(f) remedial soils action structure, several areas in the control tower 1 .ahs connection to the auxiliary bEIlding were caliifat'ed'ta'lisi' ~ ~ overstrDised'in Ioad con 6fiEtiotus with seismic' forcis~. This pre- ~ N Iiminary analysisTstributearthe safsmic'fsfees to various struc- ~ tural elements using conventional long hand asthods. Because this was not a definitive analysis,.a conclusion regardingytential y safety implication cannot be drawn. The analysis being performsd ~ for the building as modified by the 10 CFR 50.54(f) remedial soils action will demonstrate the adequacy of the final design of this structure. 4) A comparison of the in-structure response spectra curves has been ande. The greatest changes were confined to the structural steel superstructure, control tower, and electrics 1 penetration areas at el 674'-6* and above. The frequencies most affected by this change were between 4 and 10 cys. The anzimum increase in acceleration I l m

~ + e ,.- w w = , ~ + j -.036334 Bechtel Awociates Professional C~rporation k NCAR 47 1 Final Esport { Fage.3 y 4 occurred at approximately 6 cps and was 1.6 times the previous spectra values. In other areas in the building, the nas id-struc-ture response spectra did not differ significantly from the existing spectra and, therefore, by inspection, the components in t%ese areas 7 satisfy the acceptance criteria. 1 A selected semple of piping systems in the affected area were checked 'a ~ and found to meet acceptance criteria except as notad hatar. h piping systems that were selected for evaluation were located in the area ubers the greatest change in seismic loads occurred and where the pipe or hanger stresses were close to the anximum allow-li able before checking the new seismic stresses. The murt11mry stems q~ mat turbine exhaust mat, stack to the atmosphere is the only sys_ tan , found tHat could_not meet tSE airewm u gsfik. The analysis of the une stack system zor the increase in seismie loads identified one of the supports that did not satisfyl he acceptance criteria. ~ g.b 3 Decause taas support has_ a suostantial factor _againMstimate_ fail-i a ure, this does not appear to_ have_ ===e=** Japact. The analysis py g L L g (,lO 9 [ being perrormed for the 10 CFR 50 54(f) soils issue will demonstrate l 1 the adequacy of the final des?ga of this piping system. l1 ' .I t. 1 (.I / A selected semple of equipment in the aren affected were found to .l satisfy acceptance criteria. Equipment was selected to be checked 1 ' based on its ptential for change. The revised spectra were com- { pared to the spectre used to seismically qualify the equipment, 7 .i and the equipment still. satisfied acceptance criteria. o Corrective Actions Completed + 1) During the week ending January 23, 1981, the assumption that the control tower and the usin portion of the auxiliary building is a

f..

nonintegral unit between el 614' and 659' was incorporated in a t modified nodel of the==wiliary building. Accordingly, this action is complete. O 2) h structural response spectra analysis has been completed. 3 g 3) h time-history analysis ami corresponding in-structure floor p response spectra have been ponerated. 1 4) Selected equipment systems, selected piping systems, the structural steel superstructure, and the stability of the main auxiliary building have been checked. y Corrective Actions to be Completed q <j J 1) Demonstrate that the final design asets acceptance criteria. This L will be done through the 50.54(f) remedial soils action. h 1 schedule will be established in 10 CFR 50.54(f) responses. j l I l - - ~ ^ + m

T = s 1

  • 1 Bechtel Associates Professional Corporation Yb port l

L:. Page*4 E ~ 2) PSAR Section 3.7 and Specification 7220-G-7 will be changed upon completion of the 10 CFR 50.54(f) remedial soils action.

C

',2 Boot Cause f[ This asseption uns not caused by a failure to follow a procedure. All f -- procedures pertaining to the origination, checking, review, and approval of calculations were follound. This asseption involves a subjective emehnical determination of the most effective usy to anthematically model a physical feature of the structure. The methods and values used vers appropriate for the east-west direction, but detailed design reeise revealed that the methods and values used did not adequately represent the structure in the north-south direction. Because these parameters arm specifically and unigosly determined for each portion of the structure, this assumption is believed to be a random occurrence with no generic implications. Therefore, there is no generic or process corrective action planned. To support this, all undels used in the analysis of Seismic Category I were visually inspected, and no geometric situation uns identified which would lead to a mi=ilar model asseption in development of modal properties. Reportability ~' This was reported by Conomers Power Company to the ERC as a potentially reportable 10 CFR 50.55(e) item on January 21, 1981. To date, it has not 'l been established whether this ites is " reportable" under the criteria of n '. 10 CFR 50.55(e). The final design oder the 10 CFR 50.54(f) soils is. sue h]. will aliminate the safety 4=a14eistions (reportability), if any, addressed by this EAR. ]

{

.,re,aredbyf

s. S.w 7

y S.L. Sobkowski d' l Approved by: N Y N. Sean Z f 3 (f Concurrence by: IJ. Beyey r. [ l? 1

J g

i. L-W- w=.

_ _ n a... - o Nedd dnld3 7 e n ) ^ p // W GEOTECHNICAL ENGINEERS INC. u aw 1017 MAIN STREET.WINCHESTER. Mp SSACHUSETTS 01890 (617) 729-1625 n::, m gj,ggg September 23, 1983 Project 81907 ooma cm File 2.0 Ref: 81907-29 .c Mr. Joseph Khne NRP. Project Officer U. S. Nuclear Regulatory Commission Division of Engineering, M/S P-214 Washington, D.C. 20555

Subject:

Comments on Applicant's Proposed Findings of I Fact and Conclusions of Law on Remedial Soils Issues, dated August 5, 1983 Before the-ASLB Midland Underpinning t]

Dear Mr. Kane:

Following your request we have reviewed the above-referenced document and provide our comments below on those items relating to the Auxiliary Building and the Service Water Pump Structure. The page and paragraph number referred to precedes each comment. AUXILIARY BUILDING ] } occurre. p 163 1216 - The differential settlements that have i d to date may have developed stresses in the range of kg 10,000 to 25,000 psi in the reinforcing bars at critical loca-1 .I tions in the structure. These stresses are reasonably com-I patible with observed cracks, with computations by the applicant and with the measured differential settlements. 3 The amount of differential settlement causing the above stresses probably-is in the range of 0.1 to 0.15 in., or more, between the north and south side of the Control Structure. Thus small differential' settlements of this stiff structure cause relatively high stresses. One cannot interpret the fact that these settlements are small and not unusual as an indica-tion of satisfactory performance without separate justifica-tion of that conclusion based on the stresses for which the structure is to be designed. (,huf dtOV SIad3 man ImOihed as b N M h%ee NEPA.04xvt,$ l ~ Q,,i+ k vsd m MRC. blig? l

L x. 2 .x , ss nu ~ o Mr. Joseph Kane - Sep.tember 23, 198'3' gO

p. 164 1219 - The foundation soil of the Main Auxiliary

? -Building and of the proposed underpinning is not a glacial (J till. The. data available indicate that the foundation soils are clays that were deposited in a lake and subsequently loaded by the weight of a glacier. Apparently they were not sheared or otherwise disturbed by the glacial action. The vertical load of the glacier made these clays hard. 4. The term glacial till refers to " glacial drift deposited 4g-directly by ice, without transportation or sorting by water, E consisting generally of an unstratified, unsorted... mixture of ^ clay, sand, gravel and boulders" (Stokes and Varnes, 1955). , o.. This definition does not apply to the hard clay under the EPA's. [ s. .i 7 V

p. 165 1219 - Our understanding is that the 4-ft gap i.

d under the EPA will be filled with concrete, not compacted 7 sand, although either would be satisfactory. MO /p. 165 1220 - The foundation soil of the underpinning T wall for the Control Tower also is hard clay, rather than gla ' WP cial till, as described above. pO

p. 169 1227 - The Main Auxiliary Building is founded on

^ hard clay, not glacial till. g [oad test is to be performed in situ on the bearing stratum.

p. 170 1228 - During construction of an early pier, a l

\\% The active jacking procedure will be maintained until the a 9 time settlement curve indicates that the stage of secondary 1 consolidation has been reached. In addition, certain assump-y tions have been made about the anticipated long-term differen-tial settlements. Those assumptions should be fulfilled since -). they are the basis for design. By extrapolation of the ^~ measured secondary settlements and.the measured differential settleme,nts while the iacks are still active'. one can estimate 1 the future differential settlements for this purpose. [ derstood by the writer to mean differential settlement bet-

p. 170 1229 - The differential settlement of 0.25 in. was j

un f ween the north and south sides of the Control Tower, a [ distance of 47 ft. c .[During'the recent audit of September 14 and 15, 1983, data were' furnished by the applicant which indicated that their previous computations of stresses in the structure were ,V based on the assumption that the 0.25 in, differential settle-ment would occur between Column Line C of the Auxiliary Building and the south side of the Control Tower, a distance of 150 ft. This assumption is much less critical than that of the writer. The writer's. assumption was inferred from the testimony by Burke, Corley, Gould, Johnson, and Sozen. ~ ceorecumcAr.zwomezas mc. .-.,.<.y-~;~.. ._-----_~y .-,-,y t-,.a.,n e i.n nee, ee., e e m 'r- = ~ ~- rw' = - *

  • _w 7,

77 g g. l Mr.'Joctph Kona Szptenber 23, 1983 o The implication of the above differei. e is that the stresses in the structure provided by the applicant for those . ~, ]; cases that include differential settlement effects, are ^- 't smaller than would be obtained if a 0.25 in. differential ~1 { ~ settlement is imposed across the Control Tower. During the recent audit', however, the stresses due to this latter assumption were-provided by the applicant. The stresses were within code limits for the loading conditions-O, considered. However, they provided no allowance for stre'sses

4 that may exist after lockoff.

In addition, in the loading conditions covered, the effects of the 0.25 in. long-term dif-forential settlement were not taken into account for accident o n cr c conditions, which may or may not be significant.] b/ p.1701230 _ The applicant has taken into account only the differential settlement expected after lockoff, as described above. The stresses due to differential settlements to date'have been considered to be zero after lockoff, which p is not likely to be the casg u ess the building is lifted during underpinning. $ p ed c heermq ytrag g3 g/

p. 172'1233 - The fill under"the FIVP3s is not expected

~ to be compacted to 95% relative density. The criterion is: dblkh compact to 95% of the maximum density determined in accordance i with ASTM D-2049 (vibration) or D-1557 (impact), whichever is' larger. h The underpinning is founded on hard clay, not on glacial e till. Q .:v., The main portion of the Main Auxiliary Building is -, ~ ~ founded on hard clay, not on glacial-till. AgL WI

p. 174 1237 - Not all of the instruments are installed.

~ F)W away from the immediate area of construction activity since A movements in the immediate area are required to be monitored. Care is needed during construction to avoid damage to some of the instruments. u W

p. 175 1237 - Th'ere is one gap in the settlement d'ata for 3

F this structure. There are no data available, to the writer's o: i' k nowledge, for settlements that occurred during the first year or so af ter construction of the Main Auxiliary Building. n

p. 176 1238 - The writer does not consider the analysis 3({j made to be "very ' conservative. "

[The readings that' have been i

  • made to date during underpinning indicate that the computed i

stresses due to a given movement agree very closely with the-measurements.] Some of the loading combinations considered may be considered conservative by some. l, - I ~ -

. x__ _ .=.nn c. ,..a Mr. Jonsph Kcna September 23, 1983 L, i

p. 176 1240 - It was the intent, during the audits, that if the alert level is reached, every effort should be made by the applicant to-prevent the action level from being reached.

If the action levels were reached nevertheless, then emergency p action would be taken to prevent further displacements.

p. 178 1243 - The comments given above detract somewhat i

f rom the generality of this statement. In particular, if the existing stresses in the structure due to previous settlements are not removed during underpinning, then the computed stresses in the structure due to the design load combinations will be higher than those computed by the applicant in some critical locations. The underpinning system itself is F: designed conservatively. SERVICE WATER PUMP STRUCTURE _l

p. 181 1248 - There are zones in the SWPS where the j

g cracking is consistent with the stresses that would be expected due to the partial weight of the overhang. The ' north-south differential settlement of 0.25 in, is small. ., J 4 However, this structure is very st.iff. Therefore, the magni-j tude of 0.25 in. is not necessarily small for this structure. [

p. 184 1254 - The dewatering will be sufficient to pre-N vent blowup into the excavations for the underpinning piers.

i ? The 2-ft drawdown below the excavation is the minimum drawdown.

p. 185 1258 - A load test will be carried out in the bot-

$ N tom of one of the early piers to check that the compressibi-lity and bearing capacity of the foundation soil is as -<A expected during design. s Sincerely yours, GEOTECHNICAL ENGINEERS INC. ~ ~ C Steve J. Poulos Principal SJP:ms --}}

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