Elimination of Flat Plate Punching Failure Mode

A design concept that eliminates the punching failure mode of flat plates is verified by testing, and design recommendations are given. Only standard reinforcement is used, which is so easy to fabricate and rapid to install that the solution should be suitable as standard practice for ordinary flat plates as well as for such extreme applications as airraid shelters. The system provides excellent safety against progressive collapse of flat plate buildings, a basic requirement that seems to be overlooked in many current concrete codes. The provisions of the ACI Code 318-95 for two-way shear capacity of slabs are found unsafe for critical sections outside shear reinforcement and presumably also around large columns.