Nonlinear 3D Finite Element Analysis of RC Flat Slabs with High-Strength Steel Subjected to Punching Shear

Structural engineers are hesitant to take advantage of using higher strength reinforcing steel in design of flat concrete slabs permitted in the ACI 318 building code (2019) due to lack of adequate understanding of the punching shear behavior of such slabs. This study aims to construct an experimentally validated 3D nonlinear finite element (FE) model of concrete flat slab panels supported by an interior column to evaluate the effect of the changing yield strength of reinforcing steel (345–709 MPa) and the column cross-sections aspect ratio (1:1 to 1:4) on the punching shear failure of the slab. Good agreement between the FE model and tested specimen for load–deformation curves was obtained. The parametric study results indicate: (1) the slab designed with higher steel yield strength (and less reinforcement) has lower punching shear strength, and (2) the slab with the increasing column aspect ratio has higher punching shear capacity, as predicted by ACI 318 code.