LAUSR

Abstract Reinforced concrete (RC) flat plates are vulnerable to punching shear failure due to small effective area for shear resistance. To strengthen the behavior of existing flat plates, use of ultra high performance fiber reinforced concrete (UHPFRC) as a laminate has been pursued. This study focuses on punching shear behavior of RC flat plates retrofitted with UHPFRC overlay (i.e., UHPFRC-RC composite flat plates). To model the axisymmetric UHPFRC-RC composite flat plate, use of the unified strength theory-based punching shear strength model was proposed. Predictions using the proposed model, when compared to existing test results of UHPFRC-RC composite flat plates under concentric load and nonlinear analysis results using ABAQUS, agreed well with the results. Additionally, from the parametric analysis results using the proposed model and nonlinear analysis, the effects of UHPFRC overlay thickness and tensile strength on the punching shear strength were identified.