A self-centering hybrid braced precast wall with replaceable U-shaped flexural plates: Experimental and theoretical analysis

A self-centering hybrid-braced precast wall with replaceable U-shaped flexural plates (UFPs), which is composed of a hybrid braced wall, post-tensioned (PT) strands, and steel wall toes, is proposed. The UFPs bolted inside the steel wall toes, which yield at the same thickness outside the plane of the steel plate when wall rocking, providing plastic bending energy dissipation. The steel wall toe made of H-shaped steel provided increased compressive strength and space for the installation of the UFPs. Four wall specimens with varying initial PT forces, UFPs of different thicknesses, and different dampers were investigated using low-cyclic loading tests. After replacing the UFPs, one wall was retested to assess its performance. The precast walls sustained significantly low damage and showed large self-centering capabilities. The maximum drift was up to 4.5%, which far exceeded the specified requirements, and the lateral load still maintained an increasing trend. When the initial PT force was increased, the bearing capacity, initial stiffness, and self-centering capacity of the precast wall increased. When the thicknesses of the UFPs were increased, the energy-dissipation capacity and self-centering capacity of the wall increased and decreased, respectively. The self-centering and bearing capacities of the repaired wall met the seismic requirements but were slightly lower than those of the original wall. The wall with UFPs performed better bearing capacity and stiffness than the wall with variable friction dampers (VFDs) before 1.5% drift. Additionally, the opening load of the wall, the load at the yield of UFPs, and the load at different compression sections were calculated and compared against the test results. The analysis method was able to predict the behavior of the walls reasonably well.