Seismic behaviour of precast shear walls connected using prestressed horizontal beams

Abstract

To facilitate the construction and the on-site quality testing, a new type of panel joints using cast-in-place connecting beams was proposed and studied. The proposed connecting beams consisted of overlapped vertical U-shaped steel bars stretching out of the wall and the footing, longitudinal pre-stressed steel strands, L-shaped steels and infilled high-strength grout. One monolithic shear wall specimen and five precast specimens were tested under simulated seismic loads. The test parameters included the presence of L-shaped steel or not, sectional depths and locations of connecting beams as well as the locally un-bond U-shaped steel bars. The effects of these parameters on failure modes, hysteretic curves, stiffness, ductility and energy dissipation capacity were evaluated. The test results indicate that precast shear walls with proposed panel joints can achieve desirable seismic behavior comparable to or better than that of monolithic specimens, and thus can be safely applied in buildings in seismic zones. The use of L-shaped steel, pre-stressed steel strands and high-strength grout effectively delayed the concrete crushing of wall toes, and thus improved the loading capacity, deformation capacity, initial stiffness, ductility and energy dissipation capacity of the precast shear walls.