ML20064C501
| ML20064C501 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 10/16/1978 |
| From: | VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | |
| Shared Package | |
| ML20064C498 | List: |
| References | |
| NUDOCS 7810200058 | |
| Download: ML20064C501 (15) | |
Text
.-
. /
.,J. O. flos. 11715/12050
'4 arch 21, 1977
!JA1-t4 69 Fevision 1, fia y 15, 1977 Revision 2,.qeptember 25, l'378 i
REPORT O!J EVALUATIO!! OF POSSIBLE DEMAGE TO Ef4 BEDDED REI:1FORCItJG STEEL DURI!;3 INSTALLATION OF DRILLED-I!i At:CHORS REACTOR CONTAINME!;T NORTH A!it:A UtJITS 1 htD 2 0
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fhCEX
- 1. 7 Fase 1.10 Puricse 1
1.12 Findings 1
1.13 Scope 2
- 1. 1 'a Apprcach 3
1.15
' Gen 0ral 3
- 1. 16 columns and Beans 3
1.17 Slots ana halls 4
1.18 Analysis 5
1.19 Colurrns 5
2.20 Slats and halls 6
1.21 Besults 7
1.22 Cclurons 7
1.23 Walls 7
1.24 Slats 8
1.25 Feactcr Containcent - Unit 1 8
1.26 Eeacter Centainment - Unit 2 9
1.27 e
9
.. - 3 L
,y-11715-72c U9/2s/in uo l
j PURPOSE
- 1. 'l The pur pose of this report is to provide an < valuation 1.11 of possible damage to embedded reinforcinq uteel in Reac tra r 1.12 Con tainments Uni.t 1 and Unit 2 durinq the installation of anchors drilled. in concrete and to determine Lf there were any effcetu 1.13 significant enough to compromise the structural design of tha reinforced concrete.
fit 1 DINGS 1.16 Investigations were conducted at the jobsite to 1.18 determine the extent of cutting of embedded reinforcing steel.
1.19 Findings are summarized below:
1.21 1.
On August 19, 1975, the special Drillco., Inc., diamond 1.23 tipped drill bit, called the "Rebar Eater" (trade name),
1.24 specifically designed to bore into concrete and to cut any interfering reinforcing steel, came into use by pin?
1.25 hancer installation draws at the site.
These drills 1.26 were used to install mechanically expanded-drilled-in anchors which generally ranged in sire up to a maximum 1.27 of 1 in. in diameter.
J 1.29 2.
Prior to August of 1975, the primary tool used on the project for drilling concrete for nechanically expanded, drilled-in anchor bolts was the Hilti Fastening Systems, 1.30 Inc., electric drill and carbide ticped bit.
Hilti bits 1.31 have been demonstrated to be inef fective as a means of cutting embedded reinforcinq steel.
Extreme pressure is 1.32 required on the drill in order to make any penetration into steel and many bits are often damaged in the 1.33 process.
A site test using a 1/2 in, diameter !!ilti bit 1.34 showed that it took two hours to penetrate 7/8 in.
into a 2 1/2 in. diameter rebar.
3.
On March 29, 1976, Engineering issued documents which 1.36 restricted cutting of rein forcing steel without
- 1. 3.7 Encineering approval, and on April 9, 1976, instructions were issued and implenented by our field forces to 1.38 en sure compliance.
4.
The only methods available for cutting reinforcing steel 1.40 in holes for mechanically expanded drilled-in
- anchors, 1.41 other than with the special Drillco bit, were with air-are equipaent, utilizing a copper-coated carbon rod and 1.42 a
welder's electrode clamp which had provision for an air supply, or with ca rbon steel drill bits.
Since the 1.44 ai r-a rc equiorent is not designed for this application and may in fact be ha 7.a rdous to the worker when so 1.45
- employed, a
thorough in~vestigation has identified only six pipe hangers on which it wa s used.
Similarly, nince 1.46 the effort required to cut a reinforcing bar with a
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y-11715-72c 09/27/78 015 2
ca rbon steel bit in extennive and' *ime consuming, 1.47 investigationa indica te thin was in extremely r.i r.=
practice.
-5.
Electrical,
- heating, ventilation, and air conditionin1 1.49 (HVAC) and 1natrumenta tion /.isciolinen use 1 only Hilti 1.50 concrete hits when drilling holen f or anchor:2 and no evidence can be found that prior to April 9, l'176, they 1.51 used air-a rc equipmen t, carbon ntael drill bit s, or ena special Drillco hit, to cut enhedjed reinforcinq steal.
- Eurther, the majority of the types of anchors used by
,1.52 these disciplines were designed to be inntalled in 1.53 embedded concrete deaths which were less than the specified cover over reinforcing steel.
6.
Ehen in te rf erences existed between a proposed location 1.55 for a drilled-in anchor and an existing embedded 1.56 1
reinforcing bar, the alt'ernatives available to craf tsman prior to April 9, 1976, were:
a.
Reposition the drill hole 1.58
-b.
If the Hilti drill bit struck a rebar of f center, 2.1 it could sometimes be deflected off the
- bar, resulting in a hole at a slight' angle which could
- 2. 2 be utilized with a bevelled washer.
c.
Install an anchor bolt in the hole an is, with an
- 2. 4
~
embedded depth equivalent to the concrete cover 2.5 over the reinforcing bar.
d.
Cut throuch the reinforcing bar and continue the
- 2. 7 drill hole to the required depth.
2.8 Cutting of reinforcing steel was only one of the four 2.10 alternatives available when boring holes for drilled-in anchors and being the most time-consuming, was the least 2.11 3
likely to have been carried out.
scope 2.14 i
These findings indicate that our primary consideration 2.16 should be with the extent of possible damage to embedded reinforcing steel when holes were drilled in concrete for pipe 2.17 hanger and support installations during the period between 2.19 August 19, 1975, and April 9, 1976.
l
y-11715-72 c 09/27/79 01%
l I
2.22 APPROACfl Ge ne ra l 2.21 R,c in f o rced concrete structures are comprisej prima r ily
- 2. M of four kinds of structural elements:
nlaba, walls,. columns, anJ 2.27 i
heams.
plahs and walls are generally reinforce 3 witn uniformly 2.24 npaced, orthogonal patterns of reinforcina hars, in the top and 2.30 bot to:n of
- slabs, or in the near face and car f sce of walln.
Columns and beams are generally reinforcei with grouan of clom.ly 2.31
- spacei, para llel reinf orcing ha rs, in all four facas of columns, 2.1 ?
and in the top and bottom of heams.
Orthogonal reinforce.nent in 2.33 always provided in the form of ties, uniformly scaced in columna, a
and is sometimes provided in the form of
- stirrups, uniformiy 2.34 spaced in.baams, near the supports.
The frequency of possible interferences between drill 2.36 holes and embedded reinforcing steel will decrease as the center 2.37 to center spacing of rebars becomes la rge, such as in slabs and walls as compared to columns and beams., Therefore, given a known 2.39 quantity of drill holes in a slab or wall, hored with the special Drillco bit, the likelihood of interference and damage is far 2.40 less than if the same number of holes were bored into a beam or 2.41 column.
For this reason an evaluation of structural intecrity of 2.42 columns or beams requires a more precise determination of dimage 2.43 to reinforcing steel in all elenents, while it may be possible to base an evaluation of walls and slabs on a statistical analysis 2.44 of a sampling of such elenents to determine the naximum possible damage to reinforcing steel.
Columns and Beans 2.47 The Project Structural Engineer made inspection trips to 2.49 l
the jobsite on October 21, and November 10, 1976, and identified 2.50 columns and heams having any drilled-in anchors.
Elements were 2.52 selected for analysis if they had any anchors at points of c ri tica l
- stress, or where several anchors were installed 2.53 regardless of location.
Date of installation of the anchors had 2.54 no bea ring on this selection, gubsequent to these inspections, 2.55 locations of reinforcing bars in these columns and beams were determined either by using the "R Meter" manufactured by James 2.56 Electronics, Inc., or by chipping away portions of the concrete 2.57 l
cover..
Ehere an apparent interference existed between a
2.58 reinforcing bar an:1 a drilled-in anchor for a
pi pe
- support, ultrasonic test methods were used to check the depth of embedment 2.59 of the anchor.
The amount of concrete
- cover over the har in 3.1 question was measured and compared to the depth of embednent of 3.2 the anchor.
gase 1 on these measurements, possible damage to the 3.3 bar was evaluated.
This check was made regardlens of how or when
- 3. 4 the pipe support anchor was installed.
F.a se d on a
conse rva tive estimate of the extent of
- 3. 6 possible damage to reinforcing steel in a given column or
- beam,
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y-111 n-I Ac uu/dttou un a
and knowinq the design f orcen and no nonts, an analy.in was then
- 1. 7 performs d to determine if the ravine'l capabili ty of the alev n
- equated or exceeded the ca pabil i ty r vio ire <1 by th7 original
- s. a design.
T_his approach constituted a
100 percen*.
visu.t 1 L to inspection of all beam and column
>1t* men s, and an a na ly'. iia l 3.11 e
review of those having any oossible significane damane to ernbedded reinforcinq f ro:n holar dri lled f or pina supports.
An a
1.12 result of our inspections, it wan Je te rm in <d t ha t there were no irop beams or concealed flocal) beams which required review.
3.11 i
Slabs and Walls 3,16 Inspections by our ticld forces indicated that the 3.18 highest concentrations of pipe support embedments installed with 3.19 drilled-in anchors occurred in the walls and in the underside of floors of the three steam genera tor cubicles in the Unit 1 3.21 containment.
2hin is consistent with the tact that the pipa 3.21/1 suoport embedment installation ef fort had barely bequn in the Unit 2 containment at that point in time.
3.21/2 Since structural designs for each of the cubicles are 3.23 similar, only one reactor coolant oump (HCP) side radial
- wall, 3.24 steam generator (SG) side radial wall, and one section of the crane wall, with the largest cuantity of drilled-in anchors for 3.25 pipe suppo rt s, was initially selected for anchor installation review.
Thus, in Reactor Containment -
Unit 1, the RCP side 3.26 radial wall studied was from Cubicle A, the SG side radial will from Cubicle C, and the crane wall from Cubicle B.
In Reactor 3.28 Containment - Unit 2, the RCP side radial walls had too few anchors to warrant study, the SG side radial wall studied was 3.29 from Cubicle A, and the crane wall was from Cubicle C.
Due to the existence of highly localized design loadings 3.31 on the cubicle floor slabs and the fact that the
~ locations of 3.32 c ritical sections for stress may
- vary, it was decided to investigate each cubicle floor slab in Units 1 and 2
individually.
Anchor installations at points of critical stress 3.32/1 were studied and a conservative estimate of possible robar damage was made.
In general, the procedure for anchor installation review 3.35/1 consisted of identifying all pipe support embedments having 3.36 d rilled-in anchors and plottinq their loca tions on each f ace of wall elements and on the underside of the floor slab (the floor 3.37 slab top surf ace aid nc* w trrant an analytical review).
Next the
- 3. 3 B date of installation of all drilled-in anchors for pipe supports was researched to determine which of those were installed within 3.39 the " period of concern" from August 19, 1975, to April 9,
1976.
If a
date of installation was uncertain or unknown, it wan.
3.40 a ssumed to have f allen within the period of concern (see Findings 3.41 Nos. 1 and 3).
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'y-11715-72c 09/27/78 015 s,
At this point a sta tistical analysi's was pe r formed to 1.41 determine the maximum panai nle interferences between known anchor 3.u4 locations for pipe sup orts installed during tha reurio 1 of
- concern, and a known orthogonal reinforcinq steel pattern.
311 3.45 holes for anchors installed in this period were acaumed to have been dr,illed with the' special Drillco bi t and
- were, therefore, 3.46 potentially damaging to embeddei reinforcing uteel.
In sections having two or more layers of reinforcinq 3.4F-steel in the same diraction, if the type ot irillei-in anchor 1.49-used was commercially ava ilable in a length suf ficient to reach
~
the dee per ha r, then the statistical analysis included the deeper 1.50 har as potentially damaged.
Ihis was conservative.. However, in 3.52 highly stressed areas having multiole layers of rebar, ultrasonic test methods we re sometimes utilized to determine the embedded 3.53 length of the anchor, and thus, the number of layers of rebar potentially damaged.
Assumine the maximum possible damage to reinforcing 3.55 steel in a given slab or wall, and knowing the actual yield 3.56 strength of the reinforcing steel from mill test reports, a comparison was made to determine if the loss of reinforcing bar 3.57 area was suf ficiently compensated for by bar strength properties in excess of those assumed in the cricinal desion.
In those '3.59 cases where the excess yield strength was not sufficient, the design forces and momants were reviewed for compa rison with the 4.1 section capacity as reduced by bar damage.
Ihis approach constituted a
100 percent visual 4.3 inspection of all slab and wall elements and an analytical review 4.4 of all those elements which could have been critical.
ANALYSIS 4.7 Columns 4.9
.tructural analysis v2
- columns, to determine their 4.11 S
revised capability af ter bar
- damage, was performed using the 4.12 methods of ACI 318-71 and the governing load equations of NRC 4.14 Standard Review Plan, Section 3.8.3, Paragraph II.3.
- dhere the 4.15 ultrasonic test showed pene t ra tion of a reinforcing bar by a drilled-in anchor, the anchor was assumsd to have hit daad center 4.16 and to have pe rf ora ted the bar.
In most cases the anchor 4.17 diamete r was smaller than the reinforcing har
- and, therefore, even a
dead center hit could. not completely sever the bar.
In 4.19 those instances, the damaged bar was treated analytically as one having an area equivalent to the reduced cross sectional area of 4.20 the perforated bar.
In colunns, where the location of damage to one bar was 4.22 separated f rom the location of damage to another har by a
4.23 distance equal to or greater than the development length (per ACI 31S-71) of that bar, the damage was treated analytically as 4.24
,e Mb
l y-11/15-/2c 09/ /. s / i n usa 6
only one reducti.on in croas noctiona l area ot a bar.
This in 4.25 ju 2ti fied by the fict that the two damqoi ba rn in "ffect
- 1. i p each other, and can arill trann f or loadn ca rrie<1 it t hei r rerheu l 4.29 sections by bond l<tvn lo o. ent.
The saction of "ach column thon 4.27 m
having the g rea test reduction in ha r a rea wn i f.in tif i m1, Veritication analysis was then nerformed on this critical section
- 4. 2 *l by camputer using a
S6W nrogram entitled, $11Pinne Strength 4.29 Analysis of Concrete Colu: ens."
It in based on accentei ultimate 4.10 strength theories for reintorcet concrete
- dasign, and whara a pplica ble, assumptiona and limitations conforming t) ACI 3,19-71.
4.31 slabs and Walls 4.14 statistical analysis of slab and wall eleinents to 4.36 determine.an assumed maximum nossible bar damace was nerformed 4.37 g ra ph ically.
Locations of all drilled-in anchors installel 4.39 during the period of, concern were plotted to a large scale.
Then 4.40 a
transpa rency was prepared
- showing, to the same scale, tha orthogonal rehar pattern indicated on the desian drawin7 in the 4.41 element.
'True tra nspa rency was overlaid on the anchor location 4.42 plot to determine the position of the reba r pa ttern, relative to 4.43 the
- anchors, resulting in the greatest number of bar/ holt interferences.
This was done, for each of the two directions, by 4.44 shifting the transparency, a pproxii.:a tely one inch at a time, checking interferences and computing har area reduc
- ions, until 4.45~
all possible position s of the robar pat' irn had been checked.
4.46 The reduced cross sectional area at a bar/r it interference was 4.47 computed assuming complete perforation o'.
the bar and based on a 4.48 dead center hit or quarter point hit, wh'.chever appeared closer on the craphical presentation.
4.49 In slabs and walls which were designed as singly 4.51 reinforced, drilled-in anchors in zones of compression were not 4.52 considered a
possible problem provided they were beyond tna
, cutof f point required f or anchorane of fle xural tension steel.
- Also, where the location of damage to one har was separated f rom 4.53 l
the location of damace to another bar by a distance e'Iual to or 4.54 greater than the development length (per ACI 318-71) of tha t bar, i
the damage was treated analytically as only one reduction in 4.55 cross sectional a rea of a bar, similar to the column analysis 4.56 methoi.
In portions of the cubicle floors, it was necessary to 4.58 conpa re the results of the statistical analysis with design bar 4.59 stresses.
Par stresses were computed using the load equations of 5.1
~
FSAP Section 2. 8. 2. 2.
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y-11715-72c 0'l/ 27/ 78t 035 e
7 3 ESULTS
'. 's 4
Columnn
- 5. fr Table I n ut:ma rizen the results of columna inv*atiqatml 5.8 and analyzed.
Octagonal coluonn under the 7 team qenerator 5.9 cubicle floors a re given the preface "SG" followed by the letter 5.11 designa ting the cubicle they s u pno rr.
Hecta nqula r c ra ne wall
- 5. 12 columts
'a r e de sig na te.1 by the numbars correngon lin t to e 'u.-
annulus area steal column lines which pasc radially
- through, or 3 13 on either side of, the concrete colum:i.
Where drilled-in anchors were shown to interfera with 5.15 column tie barn, the elevation was noted and renair of the aie 5.16 scheduled if required.
column capacities were therefore baseu on 5.17 an evaluation of damage to axial rebars only and no further reductions are required for tie damage.
5.18 Eany of the columns designated as having drilled-in 5.20 anchors were shown by further field investigation to be free o -F 5.21 any anchor bolt /reha r interferences.
These columns have been 5.22 tabulated
- anyway, since they were investigated, but arc identified as having no har dana ce.
These columns did not 5.23 require analysis.
Walls 5.26 Table II summarizes the results of walls investigated 5.23 and analyzed.
For each element listed, the following information 5.29 is tabulated:
1.
The percentage by which the actual minimum yield 5.32 strength f or the reinf orcinq steel for that type of 5.33 element exceeds the design yield strength.
Thus, the 5.' 3 -4 mill test reports for the ECP side radial wall of all three cubicles were reviewed to determine which cubicle 5.35 had the mininum yield value for that type -of
- element, etc.
2.
The theoretical percent of reduction in reinforcing bar 5.37 area under the following conditions:
5.18 a.
Only drilled-in anchors for pipe supports installed 5.40 during the cariod of concern could have cut 5.41 reinforcing steel regardless of the method of installation.
5.42 b.
All drilled-in anchors for cine supports could have 5.44 cut reinforcinq steel rega rd less of the date or 5.45 method of installation.
The percent reduction in reinforcing bar area was 5.47 computed by dividing the total area of reinforcing steel cut, as 5.48 O'
J 09/27/7H O l's
,y-1 1 /1'3- /2 c 55 determined by the nta tistica l
- analysis, b'y the total area or steel in that face, in that *iirection.
We beli:ve the individual cubicle elements solocted t >r 8,.50 anlaysis are representa tive of thai r res pecti ve elements in the S.51 other two cubic le s in terms of the luantity and location of
" critical period" nip 7 s mport anchors.
Thic L+ lief is baned on
's. 5 1 the fact that pipe sunnort i nsta lla ti on work proceauei concurrently in each cubicle.
In the remote event that any cubicla vall elam-ne not 5.55 analyzed could have slightly more " critical period" pine support
's.56 anchors than the respective eleinent analyzed, we have included an analysis assuming all pipe support anchors could have cut 5.57 reinforcing
- steel, regardless of the date or method of 5.59 installation, to provide an upper bound on the problem.
He 5.59 believe this assumption is unreasonable and entirely unrealistic and, therefore, we have shown only the averaca reduction -in 6.1 reinforcing har area for this condition rather than the maximum, our assessment of the reduced capacity of the wall element uses 6.2 the larger reduction in rebar area of either the " Pipe Support
- 6. 3 Anchors August 1975-April 1976 Max" or "All Pipe Support Anchors 6.4 Avg."
In order to determine whether the percentage by which 5.6
'f.he actu'al yield st'rength of the " reinforcing exceeded the design 6.7 yield was sufficient, the following relationship was developed:
F = required yield strength Ar = reduced rebar area 6.11 Fd = design yield strength Ad = design rebar area 6.12 F = Ad x Fd/Ar 6.14 Review of the results contained in Table II chow that-6.18 f or Reactor Containment - Unit 1 the reductions in rebar area are not fully co:npensated for by the actual yield strength of rebar 6.19 in the reactor coolant pump side radial wall of Cubicle A and in 6.20 the crane wall of Cubicle B.
In those instances, the design 6.21 stresses due to co.7hined thermal, differential pressure, and pipe 6.22 l
break loadinas were recompute 3 using these reductions. 'This 6.23 analysis assumed the maximum reduction in rebar arca for a given layer of rebar in one face of the wall occurred in both faces.
6.24 This is conservative.
This analysis has shown that these wall 6.25 i
elements s till meet the design criteria contained in FSAR Section 3.8.2.2.
i slabs 6.29 Reactor Containment - Unit 1 6.31 The highest design stresses in the floor slabs of the 6.33 steam genera tor - cubicles result from concentrated loads 6.34 a ssocia ted with prima ry coolant loop pipe break bumpers.
These 6.36
y-11715-72c C'l/ 27/ 7 8 035 9
stressen are hiqhly localize 1 relative to the entire floor s 1.i b
- and, therefore, an assenn.nent of potential h.tr damage, in tern:
6.37 of a percent reduction in rebar crons section21 a re.t,
wi.
directed at a
mininum 10 ft x 19 f t area of each ficor alab in j
- 6. N cach of the three steam generator cubicles.
This area includ+1 6.40 those portions of the floor slah having the hiqh?st design stresses and was also vicuilly representative of the most densel v 6.41 drilled portion of the entira floor stab.
The actual yield 6.42 strength of reinforcing steel usad tor analysin was 40 kai fo-slabs in Cubicles A and B, and 42.3 ksi for cuticle C.
6.41 Estimates of the ma ximum reduction in rebar
- araa, 6.45 assumino all pipe supoort anchors installed during the
" critical 6.46 period" could have cut rehar, were made for local portions of the 6.47 sample area in each of the three cubicles.
The design stress es 6.48 due to combined seismic, thernal, dif ferential pressure, and pine 6.49 break bumper loadings were recomonted using these reductions.
This analysis has shown that the floor slab still meets the 6.50 design criteria contained in FSAR Section 3.8.2.2.
Reac*or Containment - Unit 2 6.53 4
In Unit 2, a
more singlified approach was used to 6.54/1 minimice the need for time consuming field studies of anchor installations on the underside of the cubicle" floor slabs.
Tha 6.54/4 actual yield strength of slab bottom rebar used for analysis was 40 ksi for Cubicle A, 63.5 for Cubicle B, and 56.4 for cubicle C.
6.54/5 Therefore, only the underside of the Cuh'. ele A floor slab was 6.54/0 studied for
" critical period" anchors.
Based on e.xcerience 6.54/7 gained in Unit 1, a
15 percent reduction in radial and circumf eren tial rebar area w'as conservatively assumed for slab 6.54/E bottom rebar, in Cubicles B and C, to account for possible anchor installation damage.
Tt is noteworthy that the investigation for 6.54/5 Cubicle A showed that no pipe suoports were installed on the underside of the floor slab prior to April 9, 1976.
This fact 6.54/1 was consistent with general observations about the limited extent of Unit 2 pipe support installa tion s up to that time, and 6.54/1 highlights the conservatism of the 15 percent reduction assumed in Cubicles B and C.
The design stresses due to combined seismic, thermal, 6.-54/1 dif f erential pressure, and pioe break were recomputed using the 6.54/1 actual yield strength s of
- rebar, and conservative bar area reductions.
This analysis showed that the floor slab still meets 6.54/1 the design criteria contained in FSAR Section 3. 8.2. 2.
e T'
. _ =
,y-11715-72c 09/27/1H 015 10 TABLE I 6.59 COLUrCIS
- 7. 2 Factored Loads 7.5
'40 ment, r1 (X-Ft) 7.6 Axial I.oadn, P (Fins) 7.7 Axial 7.4 Column Base Rebarc Design i
Mo.
Elev.
Damagsd T.o a d i n 1
~
capacity with
- 7. 10 M bar D3maqo 7.11 Reactor Contain:nent - Unit 1 7.13 SG-A 14'-5" None 7.15 7.17 SG-B 214'-5" None f
7.26 SG-C 214'-5" None i
l 3
214'-5" None 7.28 7-8 214'=5" 1 bar P=6077 P=6423*
7.30 Mx=5273 Mx=5545*
7.31 My=2486 My=2616*
7.32
, 13 214'-5" None 7.34 r
18-1 2148-5" 2 bars P=5341 P=5341 7.36 M>:= 6107 Mx=8371 7.37 My=1400 My=1916 7.39 l
l 6
I Capacity figures are based conservatively on f 1:0TE:
4,000 psi while actual core samples show the ir
_ ace compressive strength is 5,307 psi. mininum.
- -= -
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e
,y-11715-72c 09/77/711 0 $5
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=
TAlt f.C I,fo *:T ' f)),
COLIIMMS Factor ed I.0 s'Is Monent, M (M-Ft)
Axial Loeids, P ( P i n:i)
Axial Column Bane Rebars Design Canacity ~Jith
- ! o.
Elev.
Damaried Loa lin T Fob,a r
%, i<ir-Reactor Con ainmant - tin i t 2 7.41 r
S G-B 214'-5" None 7.43 3-4 214'-5" 2 bars P=5667 P=5722**
7.44 Mx=1000 Mx=1121**
7.44/1 i
My=9495 My=9540**
7.44/2 4.
214'-5" 1 bar P=6269 P=6370a*
7.45 Mx=1547 Mx=1536**
7.45/1 My=7357 My=7548**
7.45/2' 10 214'-5" None 7.46 11 214'-5" None 7.47 14-15 214'-5" 1 bar P=5370 P=5727**
7.41 Mx=1886 Mx=2043**
7.49/1-My=6310 My=6833**
7.49/2 C_olumn 13-14 also had damage to one bar.
It has not been shown 7.50/4 in the table, howe ve r, because it was modeled.and ana lyze.1 compositely with column 12 and the results do not lend themselves 7.50/5 to this tabula r f orma t.
Results demonstrated that the bar damage 7. 5 0 /a:
is acceptable.
NOTF.:
- Capacity figures are based conservatively on f'c=
3, fiSO psi while actual core samples show the in-place compressive strength is 4,572 psi minimum.
e..