EVALUATION OF PUNCHING SHEAR IN FLAT SLABS

Abstract

Flat-slab construction has been widely used in construction today because of many advantages that it offers. The basic philosophy in the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments at the slab column junction which is critical. An attempt has been made to generate generalized design sheets which accounts both punching shear due to gravity loads and unbalanced moments for cases (a) interior column; (b) edge column (bending perpendicular to shorter edge); (c) edge column (bending parallel to shorter edge); (d) corner column. These design sheets are prepared as per codal provisions of IS 456-2000. These design sheets will be helpful in calculating the shear reinforcement to be provided at the critical section which is ignored in many design offices. Apart from its usefulness in evaluating punching shear and the necessary shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial phase of the design.