Punching resistance of RC flat slabs with smear reinforcement

A theoretical model is proposed for analyzing the punching resistance of re inforced concrete (RC) flat slabs with shear reinforcement for concentric l oading. Kinnunen and Nylander's and Shehata's treatments of slabs without s hear reinforcement and Andersson's theoretical model for slabs with shear r einforcement together with the results of tests found in the literature and those made by Gomes constitute the basis of the proposed model. Two failur e criteria are proposed. The first one is for the case of a failure surface reaching to the column, which is assumed to occur when a local mechanism i s formed and the shear stress in this region reaches the sliding resistance . The second failure criterion is for the failure surface occurring outside the shear reinforcement region. This is assumed to occur when the maximum principal stress at a section 1.35d (an empirical number) outside the shear reinforcement region reaches the splitting strength of the concrete.