预应力预制混凝土剪力墙抗震性能试验研究

通过后张拉高强无黏结预应力筋将分段预制墙板拼装成整体预应力预制混凝土剪力墙，剪力墙根部靠近中间位置布置若干普通钢筋以增加墙体耗能性。为比较该类剪力墙与现浇混凝土剪力墙的抗震性能，进行了3片预应力预制混凝土剪力墙和1片现浇混凝土剪力墙的拟静力试验，研究墙体的破坏过程及破坏形态、滞回及骨架曲线、位移延性、耗能能力、刚度退化、残余位移等。结果表明：预应力预制混凝土剪力墙的非线性变形集中在墙根部接缝处，导致墙体本身的损伤较小；预应力筋可提供恢复力，能有效减小残余变形；由于耗能钢筋的锚固失效，预制混凝土剪力墙的滞回曲线不如现浇混凝土剪力墙试件饱满；刚度退化早于现浇墙体，但下降段曲线较现浇墙体平缓，其刚度退化较现浇墙体缓慢；锚固失效是由耗能钢筋过密布置导致。

Experimental study on seismic performance of prestressedprecast concrete shear walls

Prestressed precast concrete shear walls were assembled by post-tensioning prefabricated panels using high-strength unboned prestressing strands. Conventional reinforcing steel was placed at the bottom close to the middle of the wall panel for the purpose of increasing energy dissipation capacity of the walls. To compare the seismic behavior of such system with that of the cast-in-place (CIP) concrete shear wall, three prestressed precast wall specimens and one conventional CIP wall specimen were subjected to cyclic reversed loading, and their lateral load behavior in terms of damage progression and failure modes, hysteretic and backbone curves, displacement ductility, energy dissipation capacity, stiffness degradation and residual drifts were studied. Results show that the nonlinear deformation is concentrated at the bottom joint for the prestressed precast concrete shear walls, which results in limited damage to the precast wall panels. The restoring force provided by the prestressing strands is able to efficiently minimize the residual drifts. Due to the anchorage failure of energy dissipation steel, the load-displacement hysteresis of the prestressed precast wall specimens is not as full as that of the CIP wall specimen. The backbone curves show an earlier deviation for the prestressed precast walls than the CIP wall, while the descending branch is flatter for the former. A slower stiffness degradation is also observed for the prestressed precast wall specimens as compared to its counterpart. Anchorage failure is caused by the over-use configuration of the energy dissipation steel.