Seismic performance and analytical model of infilled self-centering precast concrete frame

To investigate the influence of infill walls on the self-centering frames seismic performance, quasi-static tests and numerical simulations were conducted. The test specimens included a bare self-centering frame and two infilled self-centering frames with different block strength. The results show that all three specimens exhibited a “flag-shaped” hysteresis curve, indicating superior energy dissipation and self-centering capabilities to cast-in-place structures. Cracks propagation in the infill walls initially occurred along the side near the column and subsequently developed diagonally. The presence of infill walls enhances the initial stiffness and bearing capacity of the specimens, transfers the load from beam end to column base, and promotes a more uniform deformation of the frame. However, it also reduces self-centering capability of the frame. The numerical parameter analyses were performed to study the bearing capacity and self-centering ability, these parameters included the block strength, the strands prestress, and the axial force. Based on the experimental and numerical results, a four-line analytical load-displacement model for infilled self-centering frame was proposed. In this model, the resistance was provided by the self-centering bare frame and the infill walls which were represented as struts. The analytical load-displacement curve was derived by the linear superposition method. In comparison with the numerical simulation results, the analytical model demonstrates good accuracy.