NEW YORK CITY FLOOR SLAB TESTS. 



As a precedent condition to the use of any type of reinforcement in cindei concrete 

 in Greater New York, it is required that the system in question shall be submitted to a 

 load test. This load test is made on a sample floor slab constructed as nearly as possi- 

 ble under the same conditions as would be encountered in the practical application of that 

 system. The material used for applying the load is pig iron, steel billets, or any other 

 suitable material. One-tenth of the load sustained by the slab is approved for a safe live 

 load in the design of floor slabs with that reinforcement of a span not greater than that ac- 

 tually tested and otherwise constructed the same. Any variation in span, thickness of slab 

 and size of reinforcement requires a separate load test. 



In accordance with these requirements and as a precedent condition to the same being 

 used in New York City, this Company constructed and tested the systems hereafter given 

 with the results noted on each one. The materials used were Lehigh Portland Cement, 

 ordinary commercial sand, and steam hard coal cinders in the proportions of 1:2:5 respec- 

 tively. The slabs were approximately 30 days old when tested. The loads actually sus- 

 tained were in every case ten times the load for which it was approved. A distinguish- 

 ing feature of these tests consists in that the reinforcement was not a continuous sheet over 

 the whole span, but was made by lapping the ends o ( two sheets of mesh (8) inches 

 or one diamond. This lap was made at the center of the span where the greatest stress 

 would come upon it. This unusual test was made by the authorities of the Building Dept. 

 of Greater New York, in order to comply with that portion of the code which required that 

 the reinforcement- should be laid as nearly as possible to the same conditions as might be 

 encountered in practice. Inasmuch as it was desired to use this mesh in continuous work, 

 all requirements would be met in the tests as made. The result of this feature of the test 

 was a strong confirmation of the assertions of this company in this respect. In every 

 instance the slabs were tested to destruction, and in every instance the failure was in the 

 steel outside of the lap. The lap remained intact and there was not the slightest indication 

 of failure. The sheets of expanded metal were wired together at the lap every three feet 

 in accordance with standard practice. This insures the correct position of the reinforce- 

 ment during the pouring of the concrete. 



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