An Experimental Study on Punching Shear Behavior of Concrete Slabs

Abstract

In determining the punching shear capacity of flat slabs, current codes of practice usually do not consider the effect of boundary restraint against rotation. The contribution of flexural steel reinforcement is ignored by some of the code provisions. Present paper is comprised of the test results of 15 model slabs in an effort to ascertain the influence of boundary restraint, the influence of flexural reinforcement and effect of thickness of the slabs on their structural behavior and punching load-carrying capacity. Cracking pattern and load-deflection behavior of the slabs tested have also been monitored closely. Significant effect of edge restraint on the punching failure load, resulting in an enhancing of the ultimate punching strength, and effect of flexural reinforcement on the punching failure load have been noticed. The code-specified strength of the specimens was calculated in accordance with the American, British, Canadian, European, and Australian codes. It has been understood that punching shear is not effectively estimated in some codes. Thus, inclusion of the findings of the study in the design codes is expected to result in a rational design of structural systems where punching phenomenon plays a vital role.