Experimental and Numerical Investigations of Punching Shear Behavior of FRCM-Strengthened Two-Way RC Slabs

Fabric-reinforced cementitious matrix (FRCM) composites have been widely studied as they constitute an alternative solution to fiber-reinforced polymer (FRP) retrofitting solutions for steel-reinforced concrete (RC) members. This study investigated the punching shear behavior of RC slabs strengthened with FRCM composites. Different tests were first performed to determine the tensile behavior of the FRCM and the interfacial bond behavior between the FRCM and concrete substrates. These tests were used as input parameters for a three-dimensional (3D) finite-element model (FEM) for RC slabs strengthened with the FRCM under shear. Subsequently, one reference slab and two strengthened slab specimens with dimensions of 1,600 mm x 1,600 mm x 100 mm were tested under punching shear. The test results demonstrate the effectiveness of FRCM strengthening under punching shear. An automation parameter calibration process was developed to identify the input parameters of Mazars' concrete behavior law used in the 3D FEM model. The results of the numerical investigation can predict the punching shear behavior of reinforced concrete slabs with reasonable accuracy.