ML19309C371

Addendum 1 to Rept on Testing of Composite Masonry Walls

ML19309C371
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	04/01/1980
From:	PORTLAND GENERAL ELECTRIC CO.
To:
Shared Package
ML19309C369	List: ML19309C368 ML19309C371
References
TAC-12369, NUDOCS 8004080509
Download: ML19309C371 (5)

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TROJAN NUCLEAR PLANT ADDENDUM 1, MARCH 1980 TO REPORT ON TESTING OF COMPOSITE MASONRY WALLS In accordance with the request of the NRC staff, twelve additional tests of the tension espacity at the interf ace between masonry block and concrete core of composite walls were performed during the period between January 31 and February 5, 1980. These tests were conducted to supplement the data obtained in the thirteen initial tests, reported in November 1979, and further quantify P

the ultimate tensile bond stress between the concrete masonry units and the concrete core in representative composite walls at the Trojan Plant.

Locations

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for the supplemental tests were preselected from architectural drawings to represent a random sample of wall thicknesses, wall locations, and building These locations were then field verified for such considerations elevations.

as accessibility, shielding requirements, structural conditions, and interferences.

The design properties for the supplemental test composite walls were the same I

as those for the initial test composite walls.

4 As described below, the tests were performed in accordance with the initial test procedure with only minor variations therefrom. Two tests were performed at each of six locations. The first test at each location was performed with the load applied to the block side of the interface, after which a second 3

test was performed by pulling the concrete core from the block at the back side of the composite wall. To prepare the test sample, a 1-in. diameter wedge anchor was pre-set at the centerline of the test sample, then a-12-in.

diameter (11-1/2 in.1D) core was drilled 'to approximately 1 in. 'beyond the interf ace between' the masonry and core concrete. The test setup utilized a-jacking frame which was bolted to the wall and a hand pressurized hydraulic 8064080 h Ci A-1

1 ram to provide the specified loads to a 1-in. diameter rod connected to the 1-in. diameter wedge anchor. The preselected test loads were cycled five times each at intervals ranging between 2500 lbs and 5000 lbs up through 15,000 lbs, at which point if no failure had occurred, the hydraulic ram pressure was increased up to a value initiating a failure in the specimen.

e Some variations to the written test procedure were approved by the Engineer-In-Charge. These variations included reduction of the load cycle time from 60 seconds to 15 seconds, deletion of deflection measurements after the first phase of tests, and the use of a single pressure gauge for some portions of the tests.

1 Only four of the 12 test specimens failed at the interface between the core concrete and mesonry block. Seven of the 12 test specimens experienced failure primarily in the block and at the cell fill to block interface. One test specimen failed due to splitting at the anchor bolt. Of the four specimens that failed at the block-core interface, a visual inspection of the-failure surfaces indicated that, in general, no obvious areas of separation at the block-core interface were evident, except at mortar joints where the block-core interface was interrupted. All failures were sudden, clear-break type failures. No measurable deflection prior to the break was detected for the five tests performed with dial gauge instrumentation.

The ultimate load 4

and general failure mode of each of the tests are summarized in Table 1.

Due to difficulties involved in orienting the hand-held impact drill-used for the anchor bolts, there was some eccentricity between the center of applied load and the center of resistance. This was evident in the majority of the tests.

This eccentricity was measured where possible and included on the data sheets.

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Calculated tension stresses at failure for each of the tests are presented.in Table 2.

The average load at failure for the four samples that' failed at the block-core interface was 11,800 lbs and the average failure load for all tests was 11,600 lbs. The corresponding nominal tensile stresses on the interface at failure are approximately 114 psi and 112 psi, respectively.

However, if the eccentricity is included in terms of bending stress, these average maximum stresses become approximately 139 psi for the block-core failures and 137 psi for all sample failures.

The lowest block-core failure occurred at 7400 lbs (Test S-7A), and the highest failed at 19,800 lbs (Test S-1B).

This lower test may have actually been cycled ten times at 5000 lbs and may possibly have reached 10,000 lbs during an initial test which was considered invalid due to equipment malfunc-tion.

An additional contributing factor to this lower failure load was the eccentricity of the anchor bolt with respect to the jacking rod.

When the data from the five initial and four supplemental tests, which were considered to be representative of block-core tensile bond capacity, are lumped together, the average nominal tensile bond capacity, excluding bending effects, becomes 158 psi. This average val'se from the tests is a factor of 3.95 times the value of 40 psi selected as a design limit. Therefore, based on our evaluation of these supplemental test data together with the initial test data, the value of 40 psi is still considered to be an appropriate t

principal tensile stress value at the block-core interface for use in analysis of composite walls for factored load conditions.

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TABLE 1 SUPPLEMENTAL COMPOSITE WALL BOND TESTS

SUMMARY

Test Thickness Location Ultimate Load Failure Mode S-1A 24 Fuel Building 10,000 lbs Block-Core El 45 Ft S-1B 24 Fuel Building 19,800 lbs Block-Cote El 45 Ft S-2A 27 Auxiliary Building 4,950 lbs cell-Block El 77 FT S-2B 27 Auxiliary Building 10,000 lbs Block-Core El 77 Ft S-3A 27 Fuel Building 11,700 lb, Cell-Block El 77 Ft S-3B 27 Fuel Building 15,000 lbs Cell-Block El 77 Ft S-4A 34 Control / Auxiliary 7,500 lbs Cell-Block Building El 93 Ft S-4B 34 Control / Auxiliary 10,000 lbs Cell-Block Building El 93 Ft S-5A 24 Control Building 10,000 lbs Cell-Block El 93 Ft S-5B 24 Control Building 18,000 lbs cell-Block El 93 Ft S-6A NOT APPLICABLE S-7A 21 Control Building 7,400 lbs Block-Core El 45 Ft S-75 21 Control Building 14,600 lbs Anchor Bolt El 45 Ft A-4

TABLE 2 SUPPLEMENTAL COMPOSITE WALL BOND TESTS

SUMMARY

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Test p, Ult e, Eccentricity No.

Load, Ibs In.

Nominal I/

Bending 2/ Total S-1A*

10,000 1/8 96.3 8.4 104.6 S-1B*

19,800 1/4 190.6 33.2 223.8 S-2A 4,950 3/8 47.7 12.4 60.1 S-2B*

10,000 1/2 96.3 33.5 129.8 S-3A 11,700 1/4 112.6 19.6 132.2 S-3B 15,000 1/2 144.4 50.2 194.6 S-4A 7,500 1/2 72.2 25.1 97.3 S-4B 10,000 3/P 96.3 25.1 121.4 S-SA 10,000 1/16 96.3 4.2 100.5 S-5B 18,000 1/16 173.3 7.5 180.8 S-7A*

7,400 1/2 71.2 24.8 96.0 S-7B 14,600 5/8 140.6 61.6 202.2

• Block-core failure 1/ Nominal tensile stress = failure load f gross area 2,/ Bending tensile stress = f ailure load x eccentricity' + gross section modulus i

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