ML20128G790

Handwritten Memo Forwarding How Safe Are Our Large Reinforced Concrete Beams & Excerpt from Textbook Reinforced Concrete Fundamentals

ML20128G790
Person / Time
Issue date:	05/04/1984
From:	John Ma NRC
To:	Heller L, Jeng D, Lear G NRC
Shared Package
ML19263A633	List: IA-84-455, Forwards Evaluation of Concrete in Basemat,Waterford Unit Number 3. Despite Violations of Spec Requirements During Initial Concrete Pouring,Const Adequate to Ensure Structural Safety ML20127A144 ML20127A168 ML20127A834 ML20127A837 ML20127B613 ML20127C060 ML20128G376 ML20128G592 ML20128G691 ML20128G710 ML20128G767 ML20128G773 ML20128G790 ML20128G826 ML20128G847 ML20128G873 ML20128G899 ML20128G920
References
FOIA-84-455, FOIA-84-A-56 NUDOCS 8505300313
Download: ML20128G790 (28)

Text

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r 33 3 m a no.m.s ENCLOSURE 1 i H t

s Il How Safe Are Our Large ,

Reinforced Concrete Beams?

e

r. - thi. e.ee, foie swi of s.

beene, wide of 4.12, 24. e4 40 In. owe -

' By C N. l. KANI seemet et time of Twente and the so- r i suhs sempwed. ble influense of the ab- * *

e. lee. depeh beseme oppered h sesh se emesse ht the eeMy behr ser % Ingest beams was ja ,

em.mee.ly de pere =4 lo m ha she enerwiw eisnte smell seems. This tread ladicates that. wieb a fe ther imeenee in depeh e , " .',

ferobe dearoese is k seMy fester ese be es-puh.d.- --

Ke.ewder teria.h deep beems:beams depeh:(stresseret) die east p esamise::

seinneed esserosos seesweh eeW,r Gemeers sheer l sereaf - 8h a n ecs (lessi,the meJerity of reintereed een- ,

erete beems which have been tested to fanure ,

range la deptl. from 10 to 15 in. Essestielly, these are tk beams as which aD our design praetlees and earety facters are bened. De ernmediate aim of the tee.t program described in this paper wee to ,

answe- the. queetten: How representative se, unes the test results derived from such relatively small beams for the safety factors of large beenes.

M*

In Eq. (17 2) of the ACI Code:s - '

e. - (i m e. - ,.g.) ,,,

l ne pas oneter has been included which leben late l oceoue: the inDuence of the effective depth d of the he an. thereby suggesting that beams of dit.

I ferent depths wu! have the same estety factor if 1 the se arrete strength f/ the pereentage of mein i reinfo eement p. and the sheer trum rette, e/d ) j w M/?d. are equal Yet, as we shsII see later. this "

l partie tar annuence is even greater then the -

toren. 500 pVd/M. la Eq. (1). A seenperisse of -

th&s fa ruiule and the test results which luustrate w a. l the in*fessee of p sad s/d le shown in Fig, I sad is dierw ed more ertenelvely in Referemer 3.

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[ef 4memaa! Sallure was based essentlany se 88 ""

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y tr of equGibrhea and resulted h some e.e-. .['*"' D-Z*,** **' M

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7F predictions, la partleuler the foHowing tause,

==1 ==P==ti=: '::'t::M:: Law. -~~ :::c:;:  ;

, g =hi* *= =tarr la

3. The incomme et esmervie samese en the so-d ^ er*** h*sen aw u. e yees== n==

Q*l*Q ',** *"",,',*,*,=ayg dl

, J enlied abear strense et resemasular suisserved esmer 4e teams wtenut met seentesummient is ." ,%e,,,,,,,,,,,,,

' mestaltne and een to emitted in strense emetrutsu  !

& Prov6ded that the solmfaretag tars obtate g

efseet we eneheress, heems etthmet hand beve a AU series had the some morninal percentage of

,',8,"g y main attafereement -(p se 3.40 percent) and the

. E a seer smeters teans semel, me esteersee. osm grade of concrete U.* = Seco psi). Within m

- ter deereesse es en deye se me team enernesse. '

8" Statement 1 bas besE esbetnamesen m .,._-

1. As for statement 2, eencerning the negative in-entin mage d the nan of dissonal falle,.

La. from s/d me 1A to the transition pelat 7,'et g l i.

. De of M two '- -

- ' t test MPeru seri which full Desural st* Jure was attalmed.

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i ta) Leonhardt and 1ralthere egege: 9ey, the THEORgTICAL CON $tDERAT90N5' a basmi wie ameath hers produsse esasseerably his iud eg , sg e ess,,ee one.

g,,,ynng The espectation that beams, different only in n) tarunisse reports s ". . . tasen 1 terested) d'Pth. M how diffemnt mietin @

was derind fmn the principal formula of the Q entres i asas een tenen at temeresseds .. ? * *"

l "g,g ,,, g

De substantiation of Statsmaent 3 is the ehlef

' - purposa of this paper.

l .M. e

Many hvastigatore assume, sentrary- to the 3g,,,3g, 7 (21 predicUen et the rauenal thewy edwneed in e m

. a E*I'"'" 3* that the influona of the effdw where Af denotes ultimate moment. Ar/s is the b ese l depth d on the relauve stangth of reinfereed W .

eenent e beese esista enly for depthe ernaller than , ,

15 in.1 a the chapter en annuseee of the hearn else . . e . n . . [

et their report.e Rusch. Maugli, and Mayer state: I I l I g

-n sewes that for beams tested under unnferely - n,

[

eil g e a distributed need, a abange of depth beyond a ertti- 'a4

% i  ! g,,%e .<

q l enn value does set have any inSuomeo en the lead-earrytag especity. His eretical beams depth le [ '

e

(

l 18 to 30 con (8 to 8 la).his eeneept of a arttisol ,. g en i l

bearn depth has aloe been sentiruned by the testa "*' m3 @

of For olL' Asserding to his investlantion, the unsees esser swees.- . 56 L erldeal effective depth for boems tested under

=

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s . , t i . ding m .I, ti.e enge . t. s. ease s.

em (12 to le leL)." Nowowr, la the Univoretty ,,,,,, W

$ of Tore ate tests, ne such arttical depth eeund be ese.. ,,,

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• the re'eenal theory? It was decided to provide e.taes M g

expert iental euldense to substantiate one er the see f esos y

/ ues gg U other e i the above-mentioned essertions. To me-

)p compli h this,four eerles of test beams et different ese. ,. Mea L '

e m

depthe were designed. Each series comprised w

d 9 beams W one depth only (8.12. 24, and 48 in). ,,, asas - m ci e masa. yam E. rig k i

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g D I f-seter. A the ratio of the spacing of ersche Wege lege of concrete teeth, and:

However, the spacing of erecks Ar is almost eenstant, virtually L._,

t of the beam depth.

i ,

, ) wheroes the ereck length a is greatly inDuennd M. en f/ M. 8 by a change in depth. In all the tests. the ereck epacing was approximately 4 in and did not very .

g

=

wrhen 3/Is the modulus of rupture of the eenerete. eppreciably with the beem depth. On the other

.. By dbiding Eq. (2) by the Sesural failure W Ge lege e of the fully hloped erecks 4 Enoment: was found to be prvpl to the depth d. Thus, the first impression dertved from Eq. (3) is that Afa as Tjd as pbdf,jd the relative beam strength M./Ne should decrosse

,l rathet quickly* witti intreesing beam depth.

. . - u.t .e ,one.mg e- ,.r o,e rel.,1ve , ,une,e,,. .e eenere,

... beam strength:

, . w m,,9 ,_,. ebut ,ee. ., ,e,,e _

are ___ nriestiv

--y' qalte diff. rent from those of smauer beams. Og r, m - 1 sm . l (3) 2111ustrates the t@el crack configurations of 12, 34, and 40 in beems. The developer t of For r given grade of eenerete and steel and a shorter sandery eneks between funy developed

- given lereentage of main ninforeanent, the fee. prbnery eneks has hun estensively &acused  %

ter it/'epf.) se a eenstant Therefore, the nieuwe by anus.e - 6 heem etrength N./Ne depends, emeept for e/d.

only er the ereck factor Ar/s.

The initial meantsg et a.r as introduced in Ref.

erence 3 was the creek spectag and s,the effective  % k

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, .r) 7"J E la i Y E liegth of a concrete touth. But, due to the differ- th og the name densgnation f..r the test scre ences an crack patterns among beems of different in Eeference 2. the four eernes wem designated.

depths. the crack factor Ar/s mquires a snore gen-erst definition than useg for the 124n. beams. as-2 p p However the besie espectation, that beams of gne ce depth have a smaller ereck fester is f l siewetheless true. Ignoring this fact noensitates ,,,,,,,,,_,, i the seceptance of lower safety facters for large h particulars for each beam are given in beams, as became clear from the test woults. Tables I through 4.

Smee anchorage fadures were considered to be W FROC;4A44 a spelat type of failure and outsade the scope of th a program, pricoutions wem taken to ebmi.

For beams without web reinferoement, the re-note this factor by welding ancher plates to the duction in strength eeused by premature diagonal ends of bars in the same way as described in fadure. increases with y = A./hd as was discussed Refe snee 2.

In Reference 2. Therefore, for the determination Be:suse the lenger 40-in. beems with ente a of the influence of depth en sheer failure, a rela- 6.in. e 6dth, approach a laterally unstat,le case all tively high percentage of reinfereement was 44-in beams had four lateral supports in the form

• ehosen. eorresponding to a nearly balanced crees of roller bearings just below the top surface. 5 ft section.For the chosen grade of concre's.f.* m 3000 pai, this from the center lane of the hum.

. . . i appreshnetely se p as 3.00 W reinfervement consisted of ASTat AIS de-

: pervent, the value selected for all four series.

forent hors with a specifwd minimum yield

} The crees sections of the four test series designed strer gth of 50 kai. However. differences in the acrording to the above specifiestions are shown in prop rties among bars of different dsameters re-Fig. 34>e. Fig as illustrates the leading arrense- sultel la variations in the yield strength from [

ment.

48.0 a 90.4 kai (see Tables I to 5). Because of

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depth, the nefety fac'.or of large beams een be b ge

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eensiderably smaller than for small beams. Fig. pj

$ andientes that the 4f-in. beams, when compared d

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• akN

• tothe m .

• g 6.in. beams, have e reduction in te oefety forter of up to 40 percent. hrefere.

N 4 e? af me oefety facter obtained frun testing 6.in.

-i beams is designated by a then we can espect a

! veduesd factor of asfety for the 40in. beams which may be as lew as:

i .

. . - m e tes

k. ~ 4* . .se N This sneens that design bened en date derived &C

(

. from 0 in. test beams, which rendere en apparentiv

[* '

e. eenserveuve oefety facter of 3.5. would actually M result in en equivalent 40-in. beam with a danger. W

• . F40 .44.emgest de is beam (e/d as 04) '"'IF I 8*8'87 I*'' 'I I A

3. Ne similarity of behavier esists for be s of h, u

different depths, even if they are otherwise equel.

this vos lation, and for reasons emplained in hef=*

1.e, having the same f/, s/d, y, and b. & Hn. w enee 3, pp. 001, the comparouve flemural stange beams, with e/d u 80, fall in flesure. ettelning I Na band up a 90 hat, was used in 2e enelysis 100 percent of the need carrying espeelty of the a '

of e!! fa ur beem aeries.N grade of eenerete was crees neuen, wheroes en otherwise equd 4No.

mainte med et 3000 pai, with a snealmum agr'o. boom fous in obser, etteining only some 75 pet.

gate et e of % in. and me : W. , for all of h sent of the flemurallued carrying especity of the g areas escuen. The treneluen point 7, which else @

o , varies with the been depth, moved from e/d = 0 0 q 7037 RSSULTS Q

li m a-.u-d -aa= * *=' a=

et failure v. versus e/d for the four test eerles is

=

?

m shown a Fig. 4. tilustroung the feet that beams, 'I

• m-eque S all parameters essept depth, enhmit a "

y - --

decrees og sheer strength v. with incrossing depth

d. Mer.ewr, the streng verleden of e. with re. n M oe *t--

spect t i e/d esiste in large booms, as was known to U% h to be the ease for emell besses, se .'%

l l

As esteneinty aseumed se meserenom : and

3. the nrieden of the test results is much esneller

=

so

%N Q" M

If we enesee the uttamate enement M.er the non. se e uit demens emel roleuve strength, r. em M./M,i, In. W stead of e. . e in.eeio of beem si,eng

• r, knew, Se ultimate snesnent of a beem felbng wi. y% C ni e In ebear appears eleply as: mes . J,, ,

.l st .*-

M. m r.qn W , _

Sine M le not only easy to determine, but in

• p eenere le eeleuteted anywey, the snelysis of sheer se ... .

We esos e ,-L l esfet) e reduced to the detersnineuen of the fee.

i tar e ur I .e .einuve be.m et,eng. r. m .n

,e , e * **

e:-

g ester e i failure. the test results are presented in se ... .- t M Tis 8 a dertwo from Tobies I le 4. '"

l ,

rrer rig. i, eeorei een hisione ener be de. = -e ...

dured e m* 8 o e.s e* e.e e s'

l. S tre ne esmedenal eede bule evneidWs pig, bye,;,4;,, ,( ,,g,g;,, g,,, ,g,,,gg (,, ,,,,,,

the in .uence of the abeelute value of the beem d.pm) j l 4010 ONAL/M8dlINT 135 N l14

) .N p

L

. , q.,, -

, i' . , ,.

~

me f

48 6 s. beam produced a relauve beam attength r TABLE 6.-06 CREASE IN RELAT!YE SEAM $TROFeTH wk.sh was 40.T percent lower than the evrnspond. ,g,-

DUE TO INCREA$ LNG 06pfM e

es ing value of the 6.ia. beast.

e w s. . # e , as l m 3. A critical beam depth as nported by RGsch,

, one e . . ees # es= _t e.w Haugli, and Mayes' eeuld not be obsetved in the a

g l' ".' ** tests Taking the lowest test values for the beams '

witti e/d a 3.0, the vehses for the relative beam strength are given in Table 4. ~

for the Na. beams to e/d as 90 for the 48-in, Net only is there an absence of a criucal beam -

beams. The ma'.a reason for the loss of sisillartty j depth, but the pomntage loss la strength to.

La behavler can be found in the otwieue diffences creases each une the depth is doubled. At that N &

l la the ereck pattern (Fig. 2), which d6etates the rate, sore strength is reached in appresimately _

g i

I shape of eencrete teeth. 33 e uch steps. Derefore, it appears that a beam he largest 48.hL beaan that the laboretary space with s/d = 10 and a depth of 30 ft would fail um. . ~

allowed (see FIs. 4) had s/d = Et and a lengtg der its own weight. For hisher e/d ration, this .

s 6-et et ft. The relauve beam strength at failure criti:al maximum depth is much lower. Fig. T (a) wee 913 poreset, thus not quite reaching the dont metrates the plationship of the relauve beam ,

transitten paint T. However, the curve is Fig. 5 stn A vmus beens depth, using a logarithmie produces by estrapolation a treasition point et seele along the depth amis for convenience. Each l I abouts/d a S.S. une in the eagram was obtained by joining me g 1 Beyond the transition points,i.e, whm full test values for beams of different depths, but q Desural strength of the trees section is attained, havtag the same e/d reties. [

ne significant reducties was observed la the rela- Is Fig f(b) the test values of the 6-in, beams.

tive beam strersth due to increased beam depth. (*3*"

whbh had d a 535 in are taken as a standard.

= Thus, only within the valley of diagonal faHure N resulte of all other beams indicate the pre.

must a reduction of strength due to greater beam port en of the relative strength which they have Bd*een

]

' l depth be canalded. w mpoet to a W beam of mmponeng s/d.

h.-

4. There is no indicauen that the reduction De smteet Im el 41 pemnt was obtained for .,

I in the safety factor approaches a limiting value "I ' r with inenese in beam depth. Within the teet I* '

range d = 833 to 418 in. an almost constant 1.fl6 ease of boom widst ,? I Far the previously described four aertes of

> emount of reduction was observed whenever the beesis of varytag depths (71g. 3). the width b of beam depth was doubled. N amount of redue. the 5eams was maintained at 6 in. Thus, the ratio -

tien le dependent on the e/d raus, with the of a/d wee different for each ser(es.h questaan greatest strength loss occurring at s/d = 3.0. The c) P P -k, k, k, k, h a l

m . . . . t I b) h ng m.,

l , 3 y , , ,

g ha

% e ,

e s e e e e e e MM g A 1.. i ..i b.i be 1 67 9 *

• 8t81 i

[3 g4 m.

e s t

I g

i iGR ........ (

_w

• D ..ibs ~l N-Q6 . lc N

, men h f

r,. ._ a_.e .8 b . 4d.b

?.m

• m meuramum I

-.s 3

[Qq%pg7y3, f _7M%iT-TU.'E'fyQp- - s t:trt, W myp wmm

$$y . &%jik. ea. W Q Qr& Q g

' ,$@dM5@MSMdhi

' $$DMSM45Mgut E

e

- , - - _ . - , . , , _ _ - - . - . - - . - - . - -- -m_- ,_ - - - - . . - - _ _ _ _ _ . - . - _ - - , - , ,_, - - - - - , - - - - - _ _ - - - - - - - - - - - - - -

.s s

l i

~ . . . .

l i

I ik Ch-[ E ' -

k _M N

.u m- x

-~; -_ %_[ ,_ ,,g.,

,.,,,._y g .y_nr.y x.,aq_r M F v.2 7 - ~~-

"A n w .e awera a w w must ee.e ,es

., .&.e -

N k me assume that we have leur aquel b r#.

w .

ef 8 en wWth and we beve decedamk test .eame (t+' Q ,.9

, ,3..'

- *

• m"j

. b togetherth(see Fig. Se end tb). Shee en leur m

• underge fr-e-some - p* #5 *"*. N' O ' -

4 h

.e swulung ,% se.deforma.tions.

e mre,eee. little interference he erformenee of the boome eheuld zp%.c.;i,$I$QY.$tg*p , f= B F b emme se if each beam wee tested Amevidual. g!

I . !! the four boeme were glued er east together L*?

(Fig. ge) there,would be htue ressen toEW,w.y3 es, set AA stu 5 Qfd.t - $

%, of four s.m

• Wsw narro t. .e.e.e .,,ereno, -

3.E. M 3 7_ m _q- '.i

. .e . ,,

-1. ,w or .

,e .id.--t wer neems (rig a

. r.b).,eine. .res. -

eM ec-l t'a

.- t.eierre e. w e.te mente. one .ouw other head. e four einsle homme. te ...m

. wa. - * - - ->ai--a- ..

w ei - ".e naa *

• m inw g w . seme e ,er t u=,e u .r) ,or u te.t. 5 e wng wein eene .en the one.,eere W us . u. . , ee,i .

erodi'she a emen eff-nw h M

-a' the resulte ere , resented la Fig. Ied. wh6th. for 3 r <

somparison, else elsew

,,;,, ,e,Y,e~,,c,ve,,,,,,v, ,,, --

~.f m u.u.. .the .releu.ve .. m beam o. , strengthw

.,w.see.tendt.et- u ,> ~ . - - - a = re m i.

.e e.r.t e e en-oene.e...mee e i.- *. ,adee,les(.e,les w w .sen (6 u.u..

k

, wi. e.e differenee, that of b as 24 in. (Fig. test Imateed m

suit.w were e e n i > asa ,rwuew re.

of the .u. . E g values for the four times ee i.ei .e ,e.ux. g of 8 in thus being four tknes es wide es h g,r etensord beem erese escusa (Fig. tab). marrower beams (b == 0i ever. mever escoeded ,ereent.e z!.n.). The difference, how.

ocetter which b'-

s un i d) w'-

. L'1

.i w 800%

b

/zf N

so (!

• M 5t1 1

A, so kI [ s . s*

4 t a ld"

. _.h A "

g f. . M

-- m e sd.o-l g o

,,o I

V q

m cl P P

• 4, I  ! o 2 5 p* "

q ,,

i e noo .i n p,

s'

=. sa i

-  ! :' ,;. .h.s..os s.d 3  :

E " l l d a lo.F in. ,

5_ . 4 ..

II i I

N u

.,_o,~ o e a 3 4 s s 7 s m ,,. n, - a g

- @ w c

-Y, UJ

a--

..4...........-... . - . - - - . . - . . . . ~ - - --- - " ~ =

~

~

. - > * .. ./ .

• . ~

r'ss,. ;

j l

. to be espected even in laboratory controlled The .everage or effettare crack kngth a san L,.

spetmens. Thus. 6s espected, no algnifacent in- espres ed as:

fluence e.f the tram width b on the relative beam strength r. rould be detected. In spite of the s a gi s . <

increwed width. It appears, therefore, that the  ;

emission ut the width b from any fonnulas es.

presemg the relattw beam strength of rectangular where s . denotes the theoretical length of the longest cracks in the reg 6on of maximum moments.

f reinforced eencrete beams is justified. equalir3 the distance from the reinforcement to the neutral esis:

p s , se d - ki a d(1 - k) 1

' N testa eenfirmed the espectation thaf the _

influence of th.c absolute depth of beams is sig- If the everage compressive strees in the com.

s,1ficant. By int easing the beam depth from a preeshe sene et failure is empressed by af/. (at ,

to es in e decrease in relative beam strength r. failure e is about 0.75) and the equilsbrium j

in h order of up to 40 percent has been observed eendithe 7 en C is used, we obtain:

(ese Fig. 'th). This is inere than the n azimurn influence.ever the entire range of all practieelly Pf, as of/h (5) important beams. of both, y and af/Vd a e/d of ,

I

? the ACI Code Eq. 07-3) [en Eq. 6)]. On then becomes i

[ Without the opplication of any enpropriate eermetion for the ebeelute depth of the beam, r. se f. A, , k

y the safety factors derived from testa en small 6 e ff

• p dk(1 - k) * 'd j beams padum dangerously low valuw.

• t If e.wr-reinforced trees sections are escluded.

[ Fig. 4 and 8 indicate that ne simple "siae feeter" then I is always less th n one-half. Nmfere p een be added to Eq 0) to eensider this influence.

e 40 - 4) een be replaced with good appresima-

'$ A sine facter would not only depend en the deptla i

d. but slee en the region to which the beam be* tien br %Y'k/2 se een be eern from Fig. II. For longs. If we eensider the limited raise of beams k am 9 ed k sg 4 voth functions provide the esme a represented by Fig 5. the larget beams being valui. Between these limits. the differences are 4 fi deep. et seest four regions of unntated si" neglig ble. If the modulus of rupture Fis replaced facters opPear: by ist f/ fpsy, we =heas * ~

3. The scene to she left et the mainuna poet

'** yIS *pg*g Ar e j . g(psi)

( 64. hetween e'd = to and about 31 pf, - U1 1 The seaan between e/d a 23 and appremi.

g mately es. ns, se the treassues point er the small b'*"* Sinee the term ff has dropped out,inis theoret. =.

7 leal e sproach produces the earne result as our

3. The resosa between esereaisaniety e/d e ee I **8 'A ***n see of = oredesu rdas- testa.* 1.e, that r. does not depend on the concrete t

,,,,, g ,,d e s. e ne m etreng th ff. N quantities n p. and Ar. have clearla defined physacal meanings. Designatang meeI F eurrerunn see the e-re huoms le neesmenry their wmbination, as appearing in Eq. O) by: lfie%

h N limit e/d a 9.8 is, of eeurne, only valid for F -

the 4 ft deep beams. For any other saae of beam a different number would apply, adding to the esm. Aen p,,.4 ,,* (s) g_ = piezaty of such a sies feeter. However, it. Insteed of r., we cheese as indseater of failure the rete. , en ,

• n e - e ens - ear

• q' ' i _ ,,,, n e .,

tive beem strength F., a rather simple espression E N E.a ".." E

-- for the sin f. rise een be developed. This, then, e 'i'.i'. 7 ,""'*; .9.e 'ca.;ag' c"'s'"1. I". *g ,*%

=;,';;;n;r,y, L. -_ is valid for all regions to the right of the minimum 18.4/, n' P, ,",,,".'h ."* g" pain of r. (see Fig. 8).

l e* *M W g y,,u=,g, g,f,*,,,,.=,e, ,,,**

, y, A

' ' As prevteusly suggested's and esproceed by .

Eg (48. the failure moment af een be esenputed e . no.y. ,;4 If*E

• • de em esseme me nome ess ep.

af. se r.4f" (s) d

) e est W e lesesse esess, t t where the reduction feeler e.as defined by Eq. (3). T

, 8  ?

ACI NOINR/IIAACH 1987 t& J m

57 N A f[ M k h A NEU M M M A Tedd M 2 6if Fir 1AE J* Jei_vW W GE"W W 4 --wh

--mmmw mwe mr.wwwir.M b I 6

,Y

~

w~,,

~

~

__ ,, .,. ___r --ur- -rr - r - '-

gesige

,;G.%_&.wv_m.m x ww = w"M=ML.km&ggeBS. .

8 Y'Y$$ h and by embeututing thas reelstenee lector R in Eq. (') we obtala: TAGLE 3 COblPAR50N OF M AND gXPERiblENTAL YALUE5 00fAINEO Foil THE l' R e TRA

' . " y,y

• T 04 p- sw.N$l? w sym.me

_ ION see.MINT u4 4 5 Swouse the ereck pattern of Ierse beans is *~~ ** '" ' " '

not giesretrually similar to that of small boems. " * " " "

we eminst espect ll to be independent of d. but Q,[ *a t* u '~ se t

H etherwise, secording to Eg. (0). A must be a '_ se

~ sa ~~

eenst est einee neither a not Ar depend en d. p er f.'. . - To develop a mere general formula for any "l Tm any treneitten point, r, m 100 pereent en 1.s depth d, two simple means are possible: to odd to Eq. (10) en additive term er snelude a factor

. F. . and we obtain from Eq. (falt .

l which will secount for the influence of depth.

From Fig. 5. It appare that all four lines ha v R= N about the some slope of apprealmetely 1:0. This

, , , (8/ dire tround sugeset a formula of the first tyf*. la.t Since (a/d),e is emperimentally easy se deter.

mine. this is the simplest way to determine R. For .

the IIin, beam series 30 2.00 IIP, we bew: e,sy(d)+g N .*, (Ice) d = 0.7 in,y a 2JO percent and (a/d),e es 4.5 (see Fig. 6). Thus, for J, a f #= 00.000 pel, when, for the elesw 1:0. tlw eenstant e is 9025.

R = V 332(ped.The formula for eD booms with The dinedrentage of this solutten is that for re.

, d = 0.7 in. Is therefore: Ikble determinethai of the trenettien point T rather seeurate values of the function ;(d) must be known. Sinee et present only four e, lines are e, es i MP'9 . *g 00) known. and these only for p = 100 and only for Pl.

rectangular == neuens. more emperimemal The vehdity of Eq. (IC) aan be checked egoinst **'" * * " * ' I"**"*"

• tlw rueulta of ee elewn !!In. km swin de. )

scribi d in Referene,3. By determining the trenei. The other p tien points for varying amounts of main rein. ,,,,, , ,3,,,assibihty

,, ,,,,,,,3,,, of including

,,,,,,,gy,gg a facter pre.

force sent, with r, a 10 for the tieneition point eenient hes6e depth. e g. d. as 10 in is introduced, (a/d)re. Eq. (le) is used to obtain the values Froni Fig. 8. where the trenettles points een be

. show e in Table 1. The agreement between tist seen for four different depths, we obtain for and esleulated enlues is men then eeusteetwy. d en 30 in., by interpoleuen: (e/d)re m St For d er le in the some calculauen as previously used withJ, m 00 hai produces the empression f(k)

}F .

I 808 . .* flebt 0.2 f ,, e, i 100p d

/*. . -

• * / Fig. f indicates that the less of relative strength

g. / depends not only en d but. se en entent of $7.8

/ percent, else en e/d. Einee this amount hardly jusufwe a snore semplicated formula. the fellow.

0.85- '"8 'Sprooska is, therefore. eteemmended for

[ f(h)ef the determinauen of the reducuan facter. ohnrh eensiders the amount of reinfortement p. the ab.

0.8 C ,, solute depth d.and the sheer erm retw e/d -

/

0.0!. '." e.2:s e f(k).k(l.k) , 'd W k

\ 300p j 73, 3 C

3 OJ CL2 Q3 CA QS o(,,,,,,,,,,,e,,,,,,,,,,dp,p,,,,,,,..,,.

[ this wedd aridecate a fi.surd future ratw tu F;, a when of tense;ew1[I-8) and %V8# e dwa,I fo. lure. It e usur srm e tt..a Ia .

1 ACI J. JenAt /IIARCil IN7 US  :

O

. g. . - .

-. .=

M M '% Pup)J e

M. i concrete above the supporta is not overstrissad '

g,,

TABLE 8-COMPAtt$0N OF THEC'LETICAL Af4 Such ,eene belongs to bearms design and there.

a EXPERIMENTAL VALUES OSTAINED FOR THE fore is not a shear failure.

'e TRAN5 MON POINTS FOR DEAMS 05 All bearns of the four series were tested under VAtl0US OtpfMS I

[ I' point leadings, i.e. the investigation of the be.

- , se e , s. , sie em sn ~ .

sa hav6er under uniformly distributed Ioeding has I

l{ f -

s..u, u u es met be en included in this program. The behavior I. ( * ),, . I*** " i " " " of neangular reinferad conente bums under 1 [l8 .

uniformly distributed load, es compared to point h.

I !I!

were obtained, unity has to be used insteed. In leading, has been dmuesed in Reference 2 Nj j Jl Table 8, the calculated transition points. (e/d),e, 1 )

I' [F4. (11)) are compared with the values of the CONCLU$40N

-I

. Ii four test earles shown in Fig. 5: On the basis of the retienet theory developed ,

1

- la Fig.12,the calculated lines of relatin beam in Leference 3,inervesing the been depth must ,

l L I etrength, as obtained by F4. (!!),have been added h,-9

) I to the lines of Fig. 5 representing the test values. result in eensiderable nduction of the relative i g been strength. The testa desertbed in two paper ,

g The space betwun two -.-.. "a lines has have. safirmed this conclusion.

been hatched to indicate the differenews. With the By choosing the releuve etnagth r. rather than excepuen of one point, where the test value wee l 3 pe eent below the calculated value, the for-the shear stress e. as the indicator of failure we ,f,4 4

obtain the analytical F4. (11),which produces re.

! h mula gives conservettve values for the teletive suits witMn alt percent of the test values.

m, g, strengths. In all esses, the theoreccal values are F4. (!!) includes the thne major variables en t

b'.I, eere to le percent lower than the test values. For beam strength: p, s/d, and the absolute beam U beams with sinall s/d reties, Le, which in Fig.12 depth d. Wsth the reduct; n factor r. known. the u; fall to the left of their respective sainimum value

.-_ for r., the line r. = d/s, se suggested in previous esitinuse hending moment M. een be calculated "

papers, seems to be entisfactory as long as the from l:q. (C. 4 g

M

>: ,e,,

a h

j sg d4

• m ,

fc s P a p f

y 'a 40

\\

g \p v r

d e us-deIO7? [

f 90 y d e ttA* h d s 42.s'. ,

y .40 P, e , ,,

=a , ,.py 6, v *a"' $g

~d ,3 t

(;e 3.co .I

<. ,, EI'8 9. p e 2.80% lhi g, ," ,

p,e d

[ i l 100p b a 4.0 da. f

[* l i i d I

s' 4 8 8 7 8 9 i

m @e, O I 2 3 l e b ,.

l r N 4 88-C=,wh= et use.teied e.d esse s.e el ehe ,es.n.e bee p

l mtrh.1 n: ACI MutslAL/llAttil 1987 lime 84 W i

mm_ my.m m.-g%

Swe .m y.

p-w c "mmonw id. tweiMw$,a M b aE25$If

.m-- J M_ n f 6 $ a$ .&

- , . - - - - - . . - - - - - , . _ . - . - _ . _ - . _ , . - _ _ . . - -._- _ __- ~ -.-. _ _...__,,...-. _.._ _.,. .. -_--.,__.m -

- ae e, r

~

oIP**

SimE ft Smee F. gives the percentage reduction ist beam Isase h a rease of depth of eemprwm see, to efferem -

• strength due tu o prematurely developed diagonal 8're d d **#'*"'"'"""***

j erack it is en estremelv useful indicetar of failure. ' " C '/*Jhe "*"

fu a Fwid etMagth of mets mmfmanent

! e/d a sheer enn retas

• • • • ""'"d *'"*"h" 8*8 f@$

ACaMowt.tocutwn N. m ettunate e"nement is m" depen""emas certion et ""*!

The seem deerrund in this paper == eerrwd mit am feature me intereternes et the Department of Caet1 Ensussutng ate a eskulated fleeurel enament espeesty of adspen i at me Unleersity of Terente end eposessed by the ' " * " ' " " ' '

" * "" "8 i Notasaal Seseerth Council of Caneds The auther would 88 hhe to thank m. Wataopp ser us inenauew easist , enn "erm same ensemasw'd using A he.= %"N*

In both terrytag out the tests and propanag the menu. I II sertet, and nies a F. Case who, as a muur of W re a n'isuse eseus streada r.m aforate #

erware emnddate, fabriseted and tuoted me mausuelty e. e sheer stress at Sauere on a F./h3 s ree es sa d=p heems.

ene ems- == sesa.d by e humw a., & essa #

REFERENCES ses

8. ACI Caenmittee 314. "SuDesas Code Requireements for Reinterned Cenerete iACI818 883." Amarteam Can.

erete Insutate Detroit test,144 pp.

h -

"demMesemneselesseng -

3, EenL O. N.J *Reste Poets Cemeerming Sheer fab.  ;

O' ere.* ACI Jesmaan. Pressednee v. es, sea & June less,

• 39.of8-8ek 49 6 esyneided Pueneesee Neessvee Viges Greeles

3. KenL Q. N. 2,"The Riddle et Shear Fnoure and O' E*"888' g .

. Its Solution." ACI Jovenas Preseedings V, et, Ma e, pere roepeder e este pregunte se amenyeren en le Apr.leetpoL443 487.

c' ,

Universided de Terente eustro certes de vises een t !aenhardt F, and Wahber. R. "Centruauuen to .s"*3885 8' 8' t% 84 F 40 pul adest y se sempereren -

me fruimeu et shur Prowsms am maicened Co ha essutiede Se neie uma innwneia seasiderehae des erote* (Seitrese our Behandlung due SshubpreWoune parette ofertiet a tal estremo que el fetter de segurteed

i. S=wheie.hos seis .ad smunew.he. Inoi s~e la == e6e sraad. fue v .= a Q-V. M, Na at Dee lost, and V. St Ms 3, Fok 3.mi, 03; per eienne mener gee et de les stres signs eunalems s Na 3, Mar. lost; Me6 4, June test; No. T. July test; and E888 I ^ ladie6 que sea un aumente Na 4, Aug. It!2 (4m German). See slee Twees4seien Me, " 0898'0'e'l adicismalen permite se puede superar uma dumtmuen ,.

all. Canneet and Cenerose Amnestataeg Imeden, Eaglemt sermpendesate aheast en et fortee de engarteet k immaison. M " Theory for ne Combined Aeuse 9 of Seedag kenneet and Sheer em Retafereed and Pro. .

stressed Comeme Beneen* Act Jouemat Pressed.n.e e eSe ese is e6emeied edens due poseems e.

V. et. 3tt 4, Apr. Sen, pp. 400 49L bdeen arme de goondes diamonelemet

& 8 teach, Ita HoustL F. SL; and Meyer, It. " Shear Peur rependre & eette quesuen, quatre serees de 3 feets en Berlangular Retnfereed Cenerete Seems Under poutres d'esenL opent pour heuteurs e, 33. M et es en g Uniserestr Dwnrthuted land" (im Orrmaal. Sutlette 4th 30. se et its em) est ese esser 4ee 4 rUniverehe

$44, Deutscher A* for Siehlheten, Berlin, lost, de Terente et aus semahnte eat ete semiperes. D e ese .o 73 N' *

1. ForemeR, C. "Fests of Sheet Strense and Shea, issued que la seleur de la heuteur ahealue seest we stende tanusese, le emetenesses de oesurtle t$el de le g

Seenforeement of Camervie Seems," Trumaneciens, Swed. pouwe le plus grence tunt #% plus Inible que celut 4 Ink Cement and Cenerete Reeserth lastatute at the du peutres plus peutes 4destatues per eiUeurs. Cats w Royal laattute of Techselegy, Steekheim, Ma fe, test. MC laine & pommer qu'une plus grande sugementataan de ,

8. Srema, 3. 3, " Stress Destreuues in Re6afereed Is heutur peerreLL 6tre esseepuWe de esaduire 4 une

• Cenerete asombers wem Tessesa Creeks." ACI Jessmas, d 8h88uhat emetse plus forte de esethelemt de e4rurtse res=dmes v. n n. e, Sept. tese. use.nm.

- h.

wie eiener on d weses. m seeunesee6emie., W58

- Um da= rrese se nee.i , .e,dem e. de, APPENDIX """'"* T" * '*' v = =her=hea Sah8he=aha"me=esm"e't d=. mehe e, hais, 3. esa ggggg A& hetrut Dw E

--to-.rgebause d eese gets,surhump

. e .d. e ore ~ m _e,hh.he.r.en .

,h - sh L - .nhake e e.er f d.p. m.,-te. emen en r~ .or u . e.ar

.,efshler ,em

• d . .e a depth s---a of reses emetnse to arves og se,ge ,,,,, ese grensten Snaker. een eenWwred te Present EE 3,, ==dn.e a me d. es.si .ie,rhe,U,s. hieme,e. re 6em' gmeiremen es d'#rmined en 8 a tt-an. 8884 " **'. Dew tendens se a'-a v-eree-~n. d- m.m.si, dans het een 8 8 I aree el meat retaferseeneet nha eauch temre

• Westeren Abtstt des Berherbeetssekterse see reennen set.

l acmunimacs a M m

Ws3 nm_emwg _ _ w.m w

% mm -gg_ ,

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.._..~ .. ... ... . . . _ _ _ . _ .

enclosure: 2 5.23 BEHAVIOR PATTERNS NOT YET INCORPORATED IN CODE

~

(c).Vd/Af Term for Shear in Continuous Beams * '

The allowebh ehear strees equation of the 1971 code, e, -

1.9VM+ 2600 F.dM., was Aret proposed' in 1982 es an evaluation of the ahear armeking strees, with F dM. representing the laSuense of the sheer

• eyes. T".ao 1977 Code uses this fans as the basis for its allowable F, ICede j

. Eg.11.6, shown here la See. 5.8). It was primarily based en simple span tests. ,

g In a esatianous apaa YdM and da are guite diferent and saly de  ;

leads itself to a plausible physical laterpretaties. For the misspie span with

< esmeentrated needs one sea visualise a reduelag sheer span as making feasible sa i=*li=J etrut to carry m'uch of the shear; the smaller afd 0erger d/s) means a steeper strut and one leaving less of the ahear to eense dissonal tension problems. However, apphed to a seatinuous beam, the equatica esens to imply that the pelat of iniestion aste as a reactica for the peeltive acessent length and en a lead pe64 for the negative moment length; but the P.I. furalobes neither the reestica below nor the lead above to produce the esseprenoies forees that make the simple.apan eeneopt valid. Instead, es in Fig. 5.3c, the failure line goes from real lead to real reesties and the P.L esses to have shown ne lassenes. ~.

To thlak in terms of the slope of the end stret for a seatinuous beam,

" the equaties sauet be in ternes of de and met YdM. If there le a F.L midway between lead and reesties, the strut een be ne steeper than if it were a simple spea, as ladi+=*ad la Fig. 5.23; but the use of FdM weald mesa the latusnee of this term was doubled by the shange frees simple apaa to esatinuous. 'I1 mis appears en the sneefe side, even for the diesenal ereckine lead.

? - --41y, for osadamese 6eems the auther now resemmende:

L Further study and tests to leak again at the Joint Comenittee repet equaties. "

2. That,la the interim, da be used la the equation instead of YdM.

3. That, for uniform lead, de be used as 0.35 or the overall 2VM be used, the particular de being a judgment desielen.

I s

~ Sines the t'a=-an *: Gret ereck strength equaties wee empidesty ebaalaed, one enest acknowledy that it aget met truly redest all eendeuses of toeding and ham.ng. Hence the author enus esteenes to Sec. 6.13, where the strength equation proposed and used la the Code involves saly esamte strength, percentage of seest, and Vd/M (which usueuy is een-side:ed a more sophistiested way of writing 4/s.* The a#m han "

• that this seustion is not edeausse under certain seccial cases he has jgggggggd ", ' -?y lower sheer strengths (25% low) have been fount, when amen pereentages (p - 0.cos) of high strengin sesel how been und la test ar-i- = This desseam has escurred whether smau et large bars were used, but widely speesd lary bars resuhed la saiu lower sheer strengths. Possibly this fbraher lary her adhet may result hem the ses-eentration of sheer stress hem a wide width into a relatively marrow moes la order to treeshe it by bend late the stesL Possibly such a sheer een-sentration aggravates the diagonal eension weeksees; at any rate eMinore ahears less than two.t tirds of the formule values for erscams shears have

been reeerted for susi essen.

9

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s,k , . *7" t% ",b= uc &# 4 m act u 4 a w. SAFETY EVALUATION OF THE STRUCTURAL ADEQUACY cew /=,

1. . km - , OF WATERFORD 3, BASE MAT ,.Am. ,

m .n

1. INTRODUCTION The adequacy of the Waterford Unit 3 foundation base mat in' light of the discovery of concrete cracking and water seepage in the mat Sh T lst was assessed and documented in any affidavit.I The adequacy of the same mat is reassessed in light of new infonnation. The new infonnation was obtained as a result of a one day site visit.

supplied by a geotechnical engineering' staff report performed by Dr. J. Chen.2 contained in a report performed by Mr. R. Philleo3 ,

and furnished by Ebasco Services, Inc. (Enclosure 1).

The observation of cracks on concrete surface, review of records, and interview of various individuals during the site visit are

described first. The diagonal tension cracking inside the mat is then hypothesized. The adequacy of the analysis and design methods used for the mat is reexamined in light of the new information. ~

i Conclusions and reconenendations are finally, stated.

@ 2.- Crack Observation, Record Review,',and. Interviews . 3 g _, ...__....-. .

I' visited the Waterford 3 site on March 27,1984, and observed C&f LW cracks on the ring wall and wet cooling tower walls. These cracks -

b had not been mapped or brought to sqy attention until the March 27, p, .,

M8 1984 visit. Some of the cracks were inclined to the vertical axis g.' V '

g, (perpendicular to the mat) and were joined by a crack on the mat.

M' This type of cracks seem to be more complicated and severe than the -

9.y) s puA- n-4sr E/s. 37

a. .

.,  : i ,

.e flexural cracks alone on top of the mat as previously reported.

Therefore, it deverses an in-depth evaluation. At the site. I also

{

reviewed construction records and interviewed various individuals who participated in the construction of the foundation base mat.

l Based on the review of construction records and interviews, I found that Louisiana Power and Light (LP&L) quality assurance group did

. try to make its program a success. Nevertheless, the first three blocks of concrete placement, where major cracks occurred, did have quality control problems. These problems included dropping i.- concrete beyond 5' height at times, using a concrete vibrator l improperly and providing insufficient vibration as well as sledge hammering reinforcing bars to create openings thus transmittir.g shock waves to the concrete below through vertical reinforcing bars. Deficiency notes were written for the cracking and honeycombing, and the records showed that they were repaired. A i stop work order was issued by LP&L after the concrete placement of the first three blocks. When the construction was resumed, quality i

control was improved.

3. The Hypothesis of Diagonal Tension Cracking The most dominant cracking pattern observed on top face of the mat

~

1s the numerous parallel cracks generally running in the East-West ,

direction and the lengths of cracking almost extended to the entire -

l w - --- _- _ . _ _ , - _ . _ _ . . - - -- . ---------_.----,,.-,---,,,,--,.w-.----,-----py.g_-_.,,--- - w e-em,c yy_w,,2-.-.. , , . , --yyv-

. I c .

-width of'the mat. Thistypeofcrabkingpatternsuggeststhatthe one-way slab (beam) action in the longitudinal (North-South)

-direction is predominant. Diagonal tension cracking associate ~d with this type of beam action is possible and is believed to have the most potential to cause trouble to the mat. The mechanism of ,

forming diagonal tension cracking is introduced first and the possible causes are then described.

An element at the neutral plane (axis) of the mat in the longitudinal direction would be subject to a shear stress but no

! flexural stress. Along the 45* line (diagonal) with the neutral plane, tensile stress with a magnitude equal to the shear stress will develop. When the tensile stress exceeds the tensile strength of concrete, a crack of 45' slope opens. This crack is named diagonal tension crack.. When the crack propagates away from the neutral plane, the slope of the crack changes gradually due to the j influence of flexural stress. .

The concrete placement of the mat was done in one block at a time.

The newly poured block experienced an immediate settlement about 3/4 of an inch and the existing one adjacent to it settled much

[

1ess. The restrain provided at the interface between the old and l new blocks created shear and, in turn, diagonal tension. Concrete 1

on top of foundation strip number 2 would settle more than concrete mat on top of strip number 1, because the latter is stiffer than l

[

l 1

the foriner. The uneven settlement generated diagonal tension. The differential movements within the mat due to the non-uniform nature of the foundation soil as a result of significant hydrostatic pressure change during concrete placement of the mat produced diagonal tension. Whether each individual contribution or a combination of them have created diagonal tension cracking within the mat is unknown, because the crack is not visible on the

. surface, except as a flexural crack. None of these contributions was included in the analyses performed for the mat. Thus,the effect of these contributions on the diagonal tension cracking is also unknown.

If-a diagonal crack does exist in the mat, it is possible and likely to join the flexural cracks near the top surface of the mat and those at the bottom surface of the mat. This type of through crack would permit the ground water, under hydrostatic pressure, to seep through. The effect of this type of cracks will be discussed in the next section.

4. Reassessment of the Adequacy of Analysis and Design

~ '

In my previous affidavit, I had determined that the analysis and '

design of the mat was adequate. I further stated that any

~

conclusion was not altered by the concrete cracking that had been

, discovered. This was because that the cracks were reported (as -

l 1

e e

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.r.--.,-,,__.----~--,.,.-,_-,....m,w. , _ . . - - - - - - -

" hairline" in size and believed to be the flexural cracks. This type of flexural crack was considered in the (ultimate) strength design method, which was used by Ebasco Services. Inc. in designing the mat. However the quality control problems during concrete placement and the new information on differential settlements of foundation soils and the new disenvery of some floor cracks, which had extended into the wet cooling tower wall and ring wall do point to the need of a re-examination of the adequacy of the analysis and design of the mat. - ' '

Concrete quality control problems were evaluat'ad by R. Philleo, a staff consultant on mat concrete construction adequacy evaluation task. His report concluded that the assumed concrete ~cepressive strength of 4000 psi in design was attained and the assumption was valid, that the assumed transfer of force from one reinforcing to the adjacent one through caldwelding is not altered due to l difficulties experienced during the construction, and that the bond between the concrete and reinforcing steel fs not in question.- In -

1 short, the quality control prob 1' ems were not significant enough to invalidate the original analysis 'and design.

~ ^

However, the new information on uneven s.ettlements of foundation soil and differential ground movements deserve some thiking. When one portion of the mat is pushed upward or settled down relative to l others, it creates both flexural and shear stresses. These I

S

• r stresses had not been included in the analysis, and thus not specifically designed for.

In view of the amount of surplus flexural capacity designed into tfut mat, due to other reasons, it is judged that these additional .

flexural stresses can be accommodated with no problems. However, it is less clear as to'whether.the diagonal tension capacity of the

. mat can accommodate the additional shear, resulting from uneven

~

settlement of foundation soil and differential ground movements.

The enclosure provides diagonal tension capacity and stresses in the mat in two regions where I believe that diagonal tens'on crocks were most likely to occur. The calculation was made assuaing n) uneven settlement of foundation so11 and no differential grouni ,

movements. In Enclosure 1. it is shown that the diagonal tenslon capacity is substantially greater than the diagonal tensile stresses under operating condition. Under the Design Basis Earthquake condition, there are still some mhrgins left. The lack i of physical information on the potential existence of diagonal tension cracks in the mat combined with a yet uncalculated diagonal tension stress introduced by uneven settlements of foundation soil and differential ground movements makes it difficult ~ to draw conclusions on the adequacy of the above noted margins. Therefore, additional analysis, which accounts for the actua1 soil condition ,

during concrete-placement should be performed and non-destructive

. _ _ _ _ _ . _ _ . . . . , _ . ~ , , _ _ . , - - . . . . - - _ _ . , _ . , _ , , . , _ _ - _ , _ _ _ _ _

. .: l 4

s testing should also be used to detect and locate any major diagonal tension cracks. The information, thus obtained, should further

. enhance the confidence level of the adequacy of the cracked ma't.

At present, the adequacy of the mat in terms of diagonal tension can be judged based on the information contained in Enclosure 1 and the pattern and size of surface cracks. The mat is safe under operating conditions. However, there are not enough data or.

infonnation to preclude a diagonal tension ~ failure under Design Basis Earthquake with a great confidence. When the diagonal tension capacity is exceeded within a partial mat width or over an i

entire mat width, one portion of the mat may slide downward relative.to the other along the face of the crack. This failure mode, if it were to occur, even though unlikely will be gradual and not catastrophic, because the foundation soil underneath it has adequate bearing capacity. Such a hypothesized failure mode should 1 -

have little significance on~ mat-1htegrity under the1BE ajDplant I

safety. Based on the safety margins cited above and Mr. R.

Philleo's conclusions regarding th'e mat construction adequacy, it is l ,

concluded that the mat will perform its safety functiong

~~

Opafntain Mr~hturaUn'tig'rity~0ndeFM~e~DBE}ondition3 u However, the

~

repair needed may be difficult and costly once the zigzagged type '

of a crack surface is destroyed by the hypothesized sliding action.-

Therefore, implementation of a non-destructive testing and f e

, + , - -

_. ..- ,._ ,-., ,.-,-..,,- _ ,.._- ,s

.. wurV additional analysis are recommended in 4 section of this

. evaluation.-

5. Conclusion and Recomendation The adequacy of the Waterford Unit 3 foundation base mat was reassessed in light'of new infonnation presented. It is concluded

- that the as-built mat is adequate to resist its intended design loads. This conclusion provides a basis fdr W6tedord 3 to receive its OL license insofar as the mat integrity is concerned.

/

l It is recommended that the Division of Licensing forward and direct the Louisiana Power & Light Co. to implement the following confinnatory t items.

These confirmatory items should be initiated by LP&L as soon as practical, however, they need not be completed prior to issuance of the OL license.

1. The applicant should update his crack mapping records, including observable vertical or inclined crakes in Category I structures supported by the mat, within next 30 days.

9 0

F. .j, -

2. The applicant shall propose an expanded differential settlements 7

, and crack monitoring program and associated plant technical

\. specifications within next 30 days for staff review and acceptance.

3. The applicant shall propose a surveillance program to monitor

potential rebar corrosion due to the ground water and associated plant technical specifications within next 30 days for staff review and acceptance.

4. The applicant shall propose a program, within next 30 days for staff acceptance, to selectively perform nondestructive testing of

-key mat cracks. The program should also include the procedures and schedule.for evaluation of the effect of cracks upon the concrete mat integrity. .

5. The applicant is required, within next 30 days, to either justify that its original analyses are still adequate in light of the NRC i geotechnical engineering staff evaluation or~ perform additional analyses to account for the actua'l foundation soil conditions.

l f

I 4

.i . r References

- 1. Affidavit of John S. Ma, Before the Atomic Safety and Licensing Appeal Board in the matter of Louisiana Power and Light Company (Waterford Steam Electric Station Unit 3). NRC Docket No. 50-382.

2. "Geotechnical Engineering Staff Report on Waterford Unit 3" by J.

Chen.

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REQUEST FOR ADDITIONAL 2NFOnMATIOM WATERFORS MPP ==

STRUCTURE ENC 2MEERING J. Ma's Cuestion on 4/4/84 -

Provfde ahear espacity and dessign ahear stress in the anat. in two ,

.regionsa

..A.

Bounded by column line 12M and 7FM in M-S direction and *

. ..l;. ~

T2 and R in E-w direction. This shear stress and ahead.

. **~. ompecity is misasured along she 45* line froen R columes line t.oward column 12M.

3. Bounded by solumn line 12M and 7FH in M-5 direction and colissan line R and P. This shear espacity and stress shonald be E-w direction'. . . . ,

N 3te sconse .

. m ms e. - .. . . . .

A. The ._...n,.desi T . .

yr. shea.rm.. -..a..i under stormaZ,operatiord conditi.on . ._

(LomS*' Factor == 1.0 5~

3 .

e2.ong t.he g5- une as defined is 5(K/ft.

- . , . , , , , , [The ultimate. shear sapacity of the mat. i s ,1 7 4 R/ftj wtsich~"in-

... *7:

'g ..,7 . g. .

• . ... *'. . .cludes each way) ' 98 e and M/ft.174 fress shear reinforcement K/ft..frors monormte. The 9 3'=0 center (ellallowable con.- -

. ' ',' c r e t ai unit ahear strt>4mm is es2 cvaated based on 25 M* . where S e. 0.85 and fo* are 4,000 psi. " *

. . . . ..  : ~, t . . .

, ,.j ), ., , . , , The ele'paslin shear stream ,usader DBE leadi.9tfgcom nass.on is ,., ,

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le s. m /_i

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.The d, e., q sign inhame stres.s u..n.e.er d o u.peration m v. un.or.ma..l._,e o Juonditlen As

3. -

d the ultimate shear capaatty ,same as 52 "A*,

s.--< M. ./. f t ,

• 274

.,.*.*.',..:.R / f t .4' .

_ ...'.*P***. . . .. , . . n m .o. .

The design ahear stress under Dag loading cornhinatiosa is .

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