IR 05000320/1974008
| ML19207B235 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/14/1975 |
| From: | Haynes R, Varela A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML19207B234 | List: |
| References | |
| 50-320-74-08, 50-320-74-8, NUDOCS 7908230649 | |
| Download: ML19207B235 (9) | |
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ROt!ISSION j
DIRECTORATE OF REGUL\\ TORY OPERATIONS
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REGION I
RO Inspection Repert No:
50-3.7/74-08 Docket No: sn wn
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Licensce: _yne-ren14,- t d i r e, e c r.,.,.,,,
License No: CPPR-66
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I Box 542 Priority:
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f Reading. Pennsylvanin 10603 Category:
i Location: Middletown, Dauchin Ccunty. Pa. (Three M41a Te'nd af eguards S
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Group:
Type of Licensee: Pk'R. 8 71 %'e (P t,in Type of Inspection:
Soecial. Announced Dates of Inspection: Decenber 5. 9, 19 and_30. 1974 Dates of Previous Inspection: _
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Reporting Inspector:
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Xnthony 1. Varela, Reactor Inspector Date i
Accompanying Inspectors:
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Reviewed By:
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I R. C. Haynek, Senior Reactor I,nspectoT"
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S W.ARY OF FINDINGS Enforce =ent Action
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Not applicable
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Licensee Action on Previously Identified Enforcement Ite=s Not applicable
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Design Changes The licensee is censidering changes in tendon wire and wedge design, and has conducted tests during the =onth of Dece=ber, 1974 to demonstrate their accept-
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ability in accordance with PSAR co==1t=ents and, as agreed at =eeting with the Directorate of Licensing October 21, 1974.
(Details, Paragraphs 1, 2 and 3)
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Unusual Occurrences Not applicable
Other Significoat Findin2s
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Not applicable i
Manage =ent Interview No for=al canage=ent =eeting was held by the RO inspector.
The inspector's findings presented in the details of this report are the results of his observa-tions of the testing.
The details also include preliminary results of the
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j available raw data he collected during and after so=e of the tests.
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Representatives cf the l'icensee, the AE, the constructor and the vendor of the prestressing syste= were present during tests, conducted at Wilkes-Barre, Pennsylvania, and Lehigh University at Bethlehe=, Pennsylvania on Dece=ber 5, 9, 19 and 30, 1974, to test for acceptability the revised geo=etry tendon anchor wedges and the low relaxation strands manufactured by Florida Wire and Cable Co=pany (FWC).
The R0 Inspector was infor=ed by the licensee that all test data will be analyzed by the vendor and the AE for presentation to the Directorate of Licensing in =id-January 1975.
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General Public Utilities Service Co=cany
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l Mr. J. H. Wright, Resident Civil Engineer, Site
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Mr. L. Caribian, Structural Engineer, Parsippany Office Burns and Roe
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Mr. L.14nkow, Proj ect Civil Engineer -
Mr. O. Mallon, Supervising Civil Engineer Stressteel Corporation Mr. M. G.
Suares, Vice President Mr. R. Bonomo, Manager, Field Operations Mr. F. Selenski, Plant Superintendent Lehigh University
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Dr.R. Slutter, Professor of Civil Engineering United Engineers and Constructors Mr.
D. Perry, Quality Assurance Engineer
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DETAILS
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Static Tests Conducted at Stressteel Plant, Wilkes-Barre, Pennsylvania 12-5-74
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a.
The inspector observed eleven static tests conducted at the Stressteel
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Plant, Wilkes-Barre, Pa. on 12/5/74 to study the effects of the redesigned 70 buttress wedge anchor on the percentage elongation at ultimate load.
Three - 7 wire
" dias. strands =easuring 14.849 f t. were pulled in a test block in each test by a 150 ton jack.
The wire is identified as
" low relaxation strand from Pack No. '287-23 obtained from the Florida Wire and Cable Company and is identified in certified test Report No. 5224 as follows:
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Test Report 5224 9/11/74
" Dia. Stabilized Strand (270 kip) Taken at rando:
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from a lot consisting of Coll / Reel Nu=bers 4287-23; Manufactured under
Specifications ASTM Designation A-416-68.
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Ulti= ate 3/S 42,500 lb.
Load at 1% exten.
39,950 lb.
Yield Str. 0.2% offset 41,550 lb.
Prop. Limit 0.02% offset 38,000 lb.
Elong. at 28,910 lb.
0.00685 in/in or in 10 f t.
0.8220 in Ulti= ate Elong. in 24 in 5.08 Area 0.1532 sq. in.
Mod,of Elasticity 27,548,550 Psi The procedure used in the static tests included the following significant items:
Pretension strands to 1500 psi on pretensioning gauge, a.
b.
Seat test wedge with wedge seating ra= (apply pressure until pretensioning gauge dial indicator = oves).
c.
Visually inspect tautness of strands for length equalization.
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Make and record initial readings.
9.1 Set elongation gauge to zero.
9.2 Measure initial wedge set (relative to wedge plate).
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9.3 Measure length out to out of bearing plates.
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9.4 Read load cell.
l e.
Start application of load.
I'j 10.1 Stopping at each load increase, read elongation and hydraulic gauge pressure at load cell readings of 100, 150, 200, 250 and 300.
10.2 Measure wedge set at load cell reading of 300 only.
10.3 Increase load continuously until failure, reading load cell and hydraulic gauge pressure at elongations of 2, 2-k, 2
, 3,
, 4, 4-, 5........
f.
Record all readings (clongation, load cell, pressure gauge, wedge set)
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at failure.
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Dis =antle test assembly for inspection.
Record details of failure mode.
h.
Determine actual failure load, co=pute net % elongation and record, b.
Ten of the eleven tests used 7 degree buttress wedges (18 serrations/ inch),
2k" long at the anchor end and 2b" long on the pull end.
The eleventh
test used 2k" long 70 buttress wedges at both ends.
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The results are sir-arized below:
i Load at Identification of i
Test No.
% Elencation Failure (Kips)*
Wire Break (s)
2.6 41.7 one strand: one wire shear at front of test wedge i
4.0 42.3 one strand: two wires cup cone at front of Jack end
4.4 42.4 one strand: five wires includ-
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ing center c.c. at front'of test wedge
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Load at Identification of Test No.
% Elongation Failure (Kips *)
Wire Break (s)
4.6 42.4+
one strand: two wire c.c.
at front test wedge & one vire c.c. 8' away from test
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wedge
one strand: one wire shear.
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I in front of jack end wedge one strand: six outside wires
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c.c. in front of jack end wedge
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3.6 42.2 one strand: seven wires, 6 outside c.c. center shear,
+ 6 ' from j ack end
4.6 42.4+
one strard: 1 wire c.c. front of test wedge & 3 wires 7 shear 2 c.c. + 16" away frem test vadge
4.0 42.3 one strand: I wire c.c. + 3'
away from test wedge
4.P 42.4+
one strand: 6 outside wires
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c.c. at front jack end wedge
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4.6 42.4+
one strand: I wire shear /c.c.
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j at front of jack end wedge
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one strand: 2 wires c.c. at front of jack end wedge i
4.6 42.4+
one strand: 4 vires c.c. )
one strand: 1 wire shear,)at front of
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2 wires c.c. 2 wires c.c. ) jack end one strand:
wedge
4.1 42.3 cra strand: 1 wire shear /c.c.)at fron l
.ne strand: 3 wires c.c.
) jack en
) wedge
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Note:
Test Nos. 4, 9, 10 & 11 id entify breaks in different strands.
- Scaled value from plot of Fb'6C Co. Test Report # 5224:
1) Ultimate B/S = 42,500 lb/ strand at Elong. in 24 in. = 5.08%
2) GUTS = 41,300 lb at 2.0% Elong.
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All of the static tests at Wilkes-Barre on 12/5/74 used a loadeell c.
that was calibr3ted by Lehigh University on 11/26/74.
However, the erratic behavior of the instru=ent =ade load readings unreliable.
The instrument is identified, " Load =eter MDX-8 Serial # 168, Transducers Inc, Santa Fe Springs, California".
Iydraulic line pressures were also recorded, using a calibrated instrument but, the inspector was infor=ed,
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the jacking ra= efficiency was unknown.
However, the inspector observed that elongation =easure=ents were accurately determined and was informed that use of the average Load Versus Elongation curve for the FWC stand was
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acceptable and accurate =eans of determining the applied load.
an 2.
Dynamic Tests Conducted at Lehigh University 12/16/74 The inspector observed the preparation, set-up, calibration and start of one of two cynamic tests started at Lehigh University Frit: Engineering Laboratory on 12/16/74.
These tests were undertaken to determine if the mini =um specified ulti= ate strength of the " dia=eter stabilized wire could be developed, under prescribed d,yna=le loading, using the 7 degree buttress wedges.
This test used strand taken from the sa=e reel identified for the static tests.
Dr. R. Slutter of Lehigh University conducted the testing to fulfill require =ents of Guide Specifications of the Prestressed Concrete Institute, Post Tensioning Manual of 1973 as identified in Section 3.'..S(2).
The test machine used, identified Alfred J. A=sler of Schaffheuun, Switzerland, was set to cycle at about 250 to 260 cycles per minute for the first of two tests.
The guide specifications state:
"A dyna =ic test shall be j
performed on a representative specimen and the tenden shall withstand without failure, 500,000 cycles frc= 60 percent to 66" of its =ini=um speci-fled ulti= ate strength, and also 50 cycles fro = 40% to 80% of its =ini=u=
specified ultimate strength --
The cecpletion of these test on
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12/17/74 was not observed by the inspector.
The licensee informed the inspector that the same three strands were used on both dyna =ic tests and they withstood the tests without evidence of wire failure.
The results of these tests will be presented to D.L.
in mid-January, 1975.
The inspector calipered a specimen of the strand used before testing and observed that the individual and aggregate diameters of the 7 wires conformed to the requirements of ASTM A 416-68, Grade 270, for no inal
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dia=eter and nominal steel area of the strand. The center wire =easured 0.170" and the outside wires 0.165" in diameter.
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3.
Full Scale Teddon Tests at Lehigh University 12 /19 and 12/30/74 a.
Test No. 1.12/19/74 A full scale test with a 21' long tendon was conducted at Lehigh University, Firt: Laboratory, Bethlehe=, Pennsylvania on 12/19/74, 1300S8
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J using strand from the sa=e reel identified in previous tests.
A 5,000,000 lb. Baldwin universal test machine was used.
The load scale instru=entation is identified as a Tate-E=ery Test Machine and bore calibration sta=ps dated 10/31/74 Dr. R. Slutter of Lehigh University conducted the testing.
The inspector was in-foc=ed that the anchor block used in this test duplicated field conditions while that at the pull end uns modified to present a
" softer" splay condition. Load cell readings at intervals of
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250,000 lbs with corresponding elongation measurement readings were observed for loads up to 1,500,000 lbs. and thereaf ter, load s
I cell readings for each " elongation were recorded.
The inspector f
observed the maximum load reading to be about 2,150,000 lb.,
however, it appeared to the inspector the first wire break occurred
I at about 2,115,000 lb.
The final results of this test were not
available at the co=pletion of this test.
The inspector was in-for=ed after this test that, pending dismantling of the test
equip =ent and the inspection of wire breaks as to condition and location, the final analysis of test results would be made at a later date.
However, it appeared frc= preltninary results that the AF's specification require =ent, that the guaranteed mini = =L yield stress be 0.90 f's, was obtained.
It appeared to the inspector that
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no wire break occurred at 85% of GUTS and the ultimate idad ex-i l
ceeded 95% of GUTS at about 3% elongation.
On 12/26/74 the licensee infor ed the inspector that a second full scale test would be conducted at Lehigh University on 12/30/74.
Inspection of Test No. 1 wire breaks had disclosed nine wires broke at the reducing collar.
The licensee added that exa=ination of the anchor end
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where the. ires broke, disclosed that the tru= pet splay angle did not ipresent the intended field condition.
On 12/30/74 the
inspector examined the wire breaks and observed that all breaks occurred at the reducing collar and they appeared to be ductile failures.
The inspector exa=1ned the reducing collar and verified by measure =ents that the 3 degree entrance angle (PSAR Appendix 3c,
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Figure 3c-6) had not been provided.
b.
Test No. 2 Dece=ber 30, 1974 i
A second full scale test was conducted at Lehigh University on 12/30/74 e= ploying a 21 f t.
tendon =ade fro = strand taken frc= the
sa=e reel identified in previous tests.
The significant difference between test No. 1 and No. 2 was the addition of the 3 degree entrance
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angle at the reducing. collar.
In addition the inspector was informed
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before Test No. 2 tha t loading beyond the yield point would be f aster
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to avoid relaxation of the wire between load incre=ents.
The inspector
recorded time intervals between load incre=ents during test No. 2 and j
co= pared them with those he had taken during test No.1.
It appears
to the inspector that test No. 1 took about ten =tnutes between the yield point and the ultimate of 2,150 Kips whereas test No. 2 took about five minutes between yield and ultimate of 2,195 Kips.
The
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percent. elongation at the latter appears to be over 4%.
No visual
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J observation of broken wires was possible during the te.st, but the sound of wires snapping was noted by the inspector to nu=ber about five between about 2,000 Kips and up to the ulti= ate.
The inspector was informed by the Stressteel Conpany after all testing was completed, that pending inspectica of the wire breaks.
expected after 1/1/75, an analysis of all test data would be made.
The licensee and AE representatives added that all
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information recorded on the various tests and Stressteel's analysis would be presented to the AE for review.
The final report was s
expected to be submitted to DL in mid-January 1975.
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