Assessment of Design Concepts for Post-installed Punching Shear Retrofitting

Punching shear is a brittle form of failure observed in reinforced concrete slab structures and occurs without any visible signs before failure. This phenomenon typically arises around the slab-column connections, due to transverse forces being highly concentrated in these areas and can cause that the column punches through the slab. This type of failure is very brittle. The unpredictability of its occurrence makes it a particularly critical and dangerous phenomenon. Several methods have been developed for retrofitting and strengthening existing flat slabs against punching shear failure using different reinforcement-types, like shear bolts, screw anchors or bonded anchors. These methods are called post-installed shear reinforcement for existing flat slab systems. This study aims to assess the safety and economic performance of the Eurocode 2 (EC2) design method for the design of post-installed reinforcement in an existing flat slab structure endangered by punching shear, using probabilistic analysis. The probabilistic analysis was conducted based on the Monte Carlo simulation technique implemented using a MATLAB code developed in the study. The reliability indices obtained for EC2 design procedure were found to be close to the EN 1990 target reliability level.