Performance of reinforced concrete slabs under punching loads

Abstract

The experimental program of this study consisted of 12 slab specimens. The parameters investigated include ratio of reinforcement in compression and tension, amount of shear reinforcement and arrangement of shear reinforcement. Flexural reinforcement ratio especially in tension had a noticeable effect on the mode of failure and ultimate punching capacity of slabs. The enhancement in the ultimate loads due to increasing tensile reinforcement ratio was ranging between 26.0 and 42.0%. Slightly enhancement (up to 12%) in ultimate loads was observed as a result of increasing compressive steel ratio. Provision of shear reinforcement was shown to be increased the perimeter of the failure. The ultimate loads were increased with the addition of single leg stirrups as shear reinforcement particularly in case of radial arrangement of shear reinforcement. The ECCS shows the most conservative prediction for punching shear capacity specially in case of using shear reinforcement and the mean predicted-to-experimental ultimate load is shown to be 0.7. The predictions following the ACI and CSA are closet to the experimental results. The mean predicted-to-experimental ultimate load is shown to be 0.8 for ACI and 0.96 for CSA. The BS provisions for punching shear analysis were shown to be overestimated in some cases, where the mean predicted-to-experimental ultimate load is shown to be 1.19.