EXPERIMENTAL STUDY ON ASEISMIC PERFORMANCE OF SUPERIMPOSED RC WALLS WITH ENHANCED HORIZONTAL JOINTS

For the Superimposed RC (SIRC) walls, when the amount of the connecting reinforcement at the horizontal joints equals to that of the longitudinal reinforcement in the precast panels, significant rocking characteristic will appear under lateral loads, and the aseismic performance could not be equivalent to the cast-in-place RC walls. To improve this situation, the "strong connection" manner for the SIRC walls is proposed. That is, through increasing the flexural capacity of the horizontal joints, the inelastic region of the SIRC walls will be transferred from the horizontal joints to the panels, inducing a seismic behavior which is more similar with that of the cast-in-place RC walls. Quasi-static test of three SIRC walls with "strong connections" and one cast-in-place RC wall was conducted to evaluate the effect of the flexural over-strength ratio of the horizontal joints to the aseismic behavior of the SIRC walls under different axial load ratios. The test results indicate that the inelastic behavior of the SIRC wall with ‘strong connections’ occurred both near the top of the protruding reinforcement in the wall panels and at the horizontal joints. The deformation manner of SIRC walls is similar with that of the cast-in-place RC walls, and the rocking deformation mode was avoided; the more the flexural over-strength ratio is, the later the protruding reinforcement yielded; the ductility and stiffness deterioration of the SIRC specimens are comparable to those of the cast-in-place specimen with the same axial load ratio, while the energy dissipation capacity of the SIRC specimens is even higher.