Closure to “Determination of Composite Slab Strength Using a New Elemental Test Method” by Redzuan Abdullah and W. Samuel Easterling

The objective of the study was to develop a method to test composite slabs using small-scale specimens instead of the usual full-scale specimens that are recommended in most codes of practice. Test 13 in Series 1 was the first trial in which the straps were placed at 150 mm on center. As large vertical separation between the concrete and the steel was observed during this test, it was assumed that this strap spacing might not be effective in preventing the steel web from curling. For the next tests in the same series, straps were placed at 100 mm. Upon comparing the results with the full-scale data, it was found that the capacity matched that found in the full-scale tests. At this point, because the objective of the test had been met, we concluded that there was no need for carrying out additional tests with strap spacing more or less than 100 mm. The restraining effect reached a plateau, as measured by the comparison with full-scale tests, and hence the shear bond strength will not be increased more than the maximum shear bond capacity with fully restrained webs for a particular configuration. Therefore straps at 100 mm are deemed sufficient and are suggested as a general rule, at least as applicable to the type of deck, dimension of the specimen, steel sheet thickness, and strap stiffness that are within the scope of this study.