ML19221A938

Reg Guide 1.122,Revision 1, Development of Floor Design Response Spectra for Seismic Design of Floor-Supported Equipment or Components

ML19221A938
Person / Time
Issue date:	02/28/1978
From:	NRC OFFICE OF STANDARDS DEVELOPMENT
To:
References
REGGD-01.122, REGGD-1.122, NUDOCS 7907110133
Download: ML19221A938 (4)

Text

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Revision 1 t @./pncg}

U.S. NUCLEAR REGULATORY COMMISSION February 1978

- b) OFFICE OF STANDARDS D

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REGULATORY GUIDE 1.122 DEVELOPMENT OF FLOOR DESIGN RESPONSE SPECTRA FOR SEISMIC DESIGN OF FLOOR-SUPPORTED EQUIPMENT OR COMPONENTS A. INTRODUCTION a naly sis of the systems or equipment supported at s arious locanons of the supporting structure lhe Cnterion 2.

't esign Bases f or Protection Against M

Cormmnee on Reattor Sateguards has been Natural Phenomena, of Appendn A.

' General De-onsulted merning thn guide and has cont urred in siga Criteria f or Nui lcar Power Plant s to 10 CFR the regulatory pounon Part 50

'I icensing of Production and i tilvanon I aahnes. regmres. m part. that nu lear power plant B. DISCUSSION struc ture s. systenr, and compor.ent s important to saf ety be deugned.o w ahstand the ef fects of carth.

Nuclear lauhiy strus tures can be approumated bs quakes w it hout le.s of capabiiny to perf orm their ntuhemathat models to pe r nut analy sn ot responses safety functions. Paragraph ta n i) of Se. non VI.

to carthquake monons. Heuuse of the large number

' Apphcanon to 'ingineerine Deugn.

.a A ppe nd ot of deg*ees of treedom that wouM be netesur y and P.

' Seismic and Geologie Siting Cri'eria for NucIcar the possible ill-conJinomng of the resulong sutiness Power Plants. to 10 GR Part Iao. ' Reactor Sne matrix it the wmplete plant were treated m a unc

Critena, reg'.tres, in part.16 utety -related struc-mathemancal model, the plant n usuaHy Jnided mto

y stenw, and comrwents ren'mn functional in ses cral separate ss stems f or analy sn purposes lhus tures.

the esent,i a M ';nutdow n Eart quake < SSE) It n n usual that there are o s or more mathemancal speedies ne use d a sunable dy n.nue analy us as models of suppornng suus tures Iath suppornny one method of ensuring that the struc:ures, sy stems.

strut ture norm nh suppuns one or more u stems or and components can withstand the seismic loads.

pn es ut qmpment

.\\lso, Jitterem moJch or the same st rus tun en.n be reqmicd for ditterent pur Sinnlarly, paragraph taH 2) of Set non VI of the same appe ndiit requires. in part. that the structures, sy s.

poses lw thesc r e.no n s the manwmant al nnideh

, crate the se n o m eu nanon d.na f or sub-tems, and components necessary f or tonnnued opera.

used to tmn without undue risk to the health and safety of the sequent se parate a n.d > se s o1 supported s s sien,s or pubhc remain functional in the es ent of an Operatmp equipment may not be sonabic f or the dctadcd lo-Basn Earthquake (OBEL Acain the use of suitable uhred anah scs of the suppornng urut ture dy namic analy sn is specified as one method of ensur-ht equipment hasmg a smaH mass relan s e to ing that the structures, sy stems, anJ tomponents can C tA omm e m um M q @bk withstand the seismie loads I nt e rat t li tli cl! cuts sin il!J siipptiil strus tuf e anJ u ill This guide describes methoJs acceptable to the need to be mluded onh m tue m.ns dninbunon or the mathemancal model f or t hat gru< tun I or su< h NRC statt for deselopme two horvontal and one ser.

tical floor deugn response westra at s arious floors or evapmem, a separate cabsn uiH be pert a mt d other equipment-support locanons of interest f rom uung the floor design < spon se spet tra r ome lo anons the time-hntory motions resulting trom the dy namic hntory c u nanons at the eqmpment-suppo '

analysn of the suppornng struaure l hese floor de-sign response spectra are necJed for the dy nanne Ims mbic when w a.c

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• derncd f rom the an dysis of the suppornng structure of the structural trequencies be broadened One ac-This guide addresses the ac cept.ibihty anJ des elop teptable method for deternumng the amount of peak ment of tbor deq n response spettra only Time-broadem og assos uted w ith cas h of the strut tural t re -

hhtory motions that w dl gne resuhs wmparable to quencies n desribed below the floor design response spettra are also Aceptable l et 1, be IL Jth mode strusiural trequenc y that n

'lhere are. howes er. other numt eqmpment s>'

deternuned f rom the mathenuncal modeh T he sana tems su< h as the rca tor t oolant sy sicm w hose sof f-tum in cash of the strut tural f requent ia is deter ness, mass. and icsulung tiequenm y range should be nuned by es aluanny the urunon due to ca h sienili considend hir in,lusion in the model of the support-cant pa ra met e r sus h as the v ol modulut maicnal mg strus ture to au ount f or pomble dy namic interas denuty, etc lhe tot.d f r eque nt y s ar ution.

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tion ettetit Suc h equipn'ent tan be analy /ed b) t see Fig l) n then deterne 'ed by takmg the square tombmmg the amplete equipment omdel with the root et the sum of squart s iSRSS) of a numnn.m ur nmdel of the supporting strutture arnt applying the iation of 0 051, and the indniJual f requent y s aru proper cuitation to the base of the supporting strut -

tions. Sti as dev A d m reculatory position I ture U ith this met hiid, i, i w parate equipnteni-surport e u.:at mn s need be pe: erateu bec ause un 11gure i show s a sample of a smoothed floor re equipment w dl x excited doutly throuch the struc sponse spech um cm s e Note that the bnudened peak l to ture li shi el. h-oted that a wmbmed mo&l of the n bounded im c Ah udc by Imes tbt are p.naNe bmidmg e ' eyaipment must bt tbrmulated to per the lines t'ornung the origmal spes tru m peak f orm sut h an analy s"

3. Floor Design Response Spettra

1. Floor Response Spectra Nucle ir power plant t ac d ine s are designed f or The two i. '/ontal and the s ertical response three-component earthpakes. as indicated m Regula-spectra can be wm;% ' trom the tune hntory mo.

tory Guide I m.

De sie n Re sponse Spe;:ra tor nons of the s uppo r t o' structure at the s anous floors Seisnuc Dcugn of Noticar Power Plant s

% hen a or other equipment-support locanons of mterest It is structural seisnus anak sn n perf ormed separately f or eA h direction itw o horizontal and one serticali. and imr Nnt that the spectrum ordmates be t on.puted at the natural f requencies ot the suppoinng structure m the case of unsy mmetn< structmt s the stromiural

.i.cls e n li C atitm w ill and itt tiequencies sutticiently (hise tai pnduse accu-nhttilm in a gis en directitill at i

rate response spectra isee I able 1 f or guidant e >

t ontain contnbunons trom tN sertn al anJ the two hon /omal cuitatmns in '< < h t nes, the wntnbunon Specuum peaks normally would be espected to occur at the nntural f requencies of the suppornng structure trom each rdnidual an tiy s.

will, encrate a re sponse spectrum al pis en h Ca!iiin in c A h til the TAlllF 1 three directoms it :s importam that th; ordmates at Sl'GGES~I ED FREQl'ENCY IN Il R V Al.S FOR these three response specha f or a pn en diret non be cal.Cl l.ATION OF RFSPONSE SPECT R A wmbmed AccrJmg to the SRS$ truenon and that the rcsulung response spectrum then be smoothed and the peaks broaJened to prcJict the floor design re Freqcency sponse spectrum at the hs anon of nuerest and for the Range Ir.crement t herth t he rt/

gn en direstion In iht t se of u nunctnc stru. tures.

there w di be onl, om upmru ant noor resp, s

. pes trum in ex h tit' the three diret tiims l he snnunhed

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s cruons of thes thior response spet tra w dl be the 3 n-3 6 n.15 T6 5.0 n 20 floor deugn response spemtra in those cases m w hn h 5 o. (o n 25 the mathemanc.d model is suba cicd sunultancoasly to the at tion o' three utnns ally mJependem spanal xo [5 o o su othquake. the three computed 15 0-Ivo In wmponente et an and smootheJ th er ro p.mse s;)ectra at a gn en losa-18.o. ;; o

o 22 o y o

o non will be the !!oor daign responst spes t r a.

C. REGULATORY POSITION

2. Smoothing Flocr Response Spectra and T he f ollow ing prm edures r t ombining and llroadening Peat s s

smoothinp the f lt u tt response spet t r J ( w llh peak s To account for unartainnes in the suus tural trc~

broadened) to obt.un the o mothed floor desien re quenties owing to unteitamties m tht m.aenal pr"P-sponse spet tra are acs ept.nle m the NRC stati erties of the structure and soil and to approumanons in the modelmg techmques used in sentmc analysn.

it is important that the computed floor response sce smu g n a., y nm g.u ac,w aa j l@

spet tro be smoothed and peaks amiciated with each spana (bar-em m s nm k m..~ wa s n e

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Figure 1 Response Spectrum Peak Broadening and Smoothing

1. When the senmic analysis is performed t epa-wbere Af;n denotes the sariation in the JtS mode tre.

rately for each of the three directions, and in the case quency, f;, due to s ariation in parameter number n, of unsymmetric structures, the ordinates of the floor and P n the number of significant parame;ers tonsid-design response spectrum at the location of ir. teres cred A salue of 0 If, should be used it the actual and for a pnen direction should be obteined ay com-computed value of 31, is less than 0.11; ll the abose bining the ordinates of the three floor response procedure is not used, Afi should be taken as n 15f i spectra lor that direction according to the SRSS

3. When the mathematical model ot' the upporting critenon. 'Ihe resulting response spettrum should be structure a subjected simultaneously to ihe acoon of smoothed w uh peaks broadened in the case of sy m-three spatial components of an tanhquake, the com-metric structures, the th>or design response spectrur..

puted response spectrum in a gnen direc mn wnh for a gnen direction will be the smoothed floor re-peaks broadened and smoothed will he the floor de-I sponse spectrum f or that threction sign response spectrum in that Jirection i

1 l o account f or i.nc ert.u ntic s m the structural D. IMPLEMENTATION trequencies ow mg to uncertainne, in such parameters material properties of the strusture and soll,

.me purpose of dus secnon a to pros iponn&

as damping s alues, soilmtructure mteracnon techniques.

non to apphtants reparthng the NR(, staf f s p ans for and the..pproximations in the modeling ;c hruque s using this regulatory guide.

used in seismic analysis, the compute,i thmr response This guide reflects < urrent NRC stati pc ictice s ettra f rom the floor time history monons should he Therefore, except in those cases in which the apph-si.os.iNd, and peaks associated w ah each of the cant proposes an acceptable alternanse method for structural f requencies should be broaJened hee the comply mg w ith specified portions of the Co nnus-sample in Figure 1) by a f requency, t af,, where sion's regulanons, the method described herein is I

being and wi!i continue to be uscJ in the es allanon of [ubmittals f or construction permit apphcanons At, -

to.n5t f + 1

( Si ny,

< 0 It' unni th's guide is resised as a result of sugges' ions n-I trom the pubhc or addinonal statt resiew 9

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