Punching resistance of slab-column connections with openings

The paper deals with the punching resistance of flat slabs with openings adjacent to a column. The results of an experimental campaign carried out at a laboratory of the Slovak University of Technology in Bratislava (STU) are presented in the paper. A total of eight slabs with a thickness of 250mm and without transverse reinforcement were tested under axis-symmetric conditions. The six slabs had two symmetrically placed openings with different distances measured from the column's periphery and two reference slabs did that not have any openings. The results obtained were compared with punching resistances assessed using the design equations introduced in Eurocode 2, Model Code 2010, ACI 318-14, and the CSCT model expressed in a closed form. Significant differences in the values of the V-test/V-R,V-c ratio were observed for the different positions of the openings for each design model. In order to increase the accuracy of the models, some changes in estimating the reduced lengths of the control perimeter were proposed.