The proposition of a method to verify the punching resistance for very large supports based on the EN 1992-1-1 standard is described in this paper. The present standard guidelines for the calculation of the punching resistance for large supports are also summarised. The proposed direct method is compared with other standard methods using an example taken from design practice. This method consists of a direct check of the shear forces at specific locations of the control perimeter with the permissible shear force calculated from the EC2 standard. The method showed very good agreement with the experiment while remaining practical for applications. The method presented takes into account the actual distribution of shear forces in the vicinity of the support, taking into account the influence of non-uniform loads, irregular floor geometry, the concentration of internal forces at the corners of the support and the influence of the stiffness of the head used. The paper provides scientists, engineers, and designers new method (called the direct method) for estimation of the punching load-bearing capacity outside the shear cap.

In the paper the problem of strengthening of flat slabs against punching shear was discussed. Selected methods verified on the basis of experimental tests such as increasing size of the support, applying post-installed shear reinforcement or increasing the main reinforcement by installing additional steel flat bars, were presented. The previous studies demonstrated, that the last method allows for an increase in punching shear resistance of up to 90%, depending on the longitudinal reinforcement ratio. The example of the application of such strengthening technique in the real structure was described. The use of steel flat bars located in the vicinity of the columns and additionally anchored to the slab made possible to compensate for the load capacity deficiencies that occurred due to execution errors (lowering of the main reinforcement within the support zones).