Experimental studies on the punching shear strength of thick reinforced concrete slabs

This paper presents the results of experimental studies on the punching shear strength of thick reinforced concrete slabs (600 mm) without shear reinforcement. The influence of the tensile reinforcement ratio (μs = 0,56% and 1,12%) on the load-bearing capacity and failure mode was investigated. It was found that a two-fold increase in the reinforcement ratio leads to an increase in punching shear strength of only 10,8%, indicating a reduced influence of this factor for "thick" slabs compared to "thin" ones. The complex stress-strain state of concrete in the support zone and the stress distribution in the reinforcement were analyzed. A comparative analysis of the experimental data with calculations based on regulatory documents (SP 63.13330, EC2, ACI 318, MC2020) was carried out, which showed a significant overestimation of the load-bearing capacity according to the SP 63.13330 methodology, especially for slabs with a low reinforcement ratio. It is concluded that it is necessary to account for the longitudinal reinforcement in the design models.