套筒灌浆搭接连接的L型预制剪力墙抗震试验

Test on seismic behavior of L-shaped precast shear wall with grouted sleeve lapping connector

摘要:

为研究套筒灌浆搭接连接的L型预制剪力墙的抗震性能,进行了1片现浇墙和2片竖向钢筋采用I型、II型套筒灌浆搭接接头（简称APC接头）连接的预制墙拟静力试验,研究了试件的破坏形式、滞回性能、特征荷载、变形、钢筋和套筒应变等。结果表明:预制墙裂缝开展情况与现浇墙基本一致,破坏形式为弯剪破坏；现浇墙破坏出现在边缘墙脚处,而预制墙底部由于套筒约束,薄弱截面上移,破坏时套筒上方混凝土压碎,钢筋压屈；当现浇和预制试件墙体底部箍筋、水平分布钢筋加密时,采用I型接头连接的预制墙的开裂、屈服、峰值荷载,刚度,延性和耗能能力与现浇墙相当,采用II型接头连接的预制墙的各项指标均优于现浇墙；两种接头在预制墙中均能有效传递钢筋应力,套筒在加载过程中基本处于弹性状态；由于APC接头刚度大,预制墙最大平面外位移绝对值小于现浇墙,但预制试件由于水平接缝影响,平面外扭转出现损伤变形累积。

Abstract:

To study the seismic performance of L-shaped precast shear walls with grouted sleeve lapping connection, we carried out quasi-static test on a cast-in-place shear wall and two different precast shear walls in which vertical reinforcements were spliced by type I and type II grouted sleeve lapping connectors named APC connectors (all vertical members precasted in concrete structures). The failure modes, hysteretic properties, characteristic loads, deformations, reinforcement strains, and sleeve strains of the specimens were investigated. Results showed that the crack development of the precast wall was basically the same as that of the cast-in-place wall, and the failure mode was bending shear failure. The failure of the cast-in-place wall occurred at the root of the wall, while the weak section of the precast wall moved upwards due to the restraint of the sleeve. The concrete above the sleeve of the precast wall was crushed and the rebars were buckled at the ultimate failure state. The cracking load, yield load, peak load, stiffness, ductility, and energy dissipation capacity of the precast wall connected by type I connectors were comparable to those of the cast-in-place wall when the bottom stirrups and horizontally distributed reinforcements of cast-in-place wall and precast walls were densified, while the above indicators of the precast wall connected by type II connectors were superior to the cast-in-place wall. The two types of connectors could effectively transmit the stress of reinforcements in the precast wall, and the sleeves were basically in an elastic state during the loading process. Due to the high stiffness of the APC connectors, the absolute value of the maximum out-of-plane displacement of the precast wall was less than that of the cast-in-place wall. However, accumulated damage deformation in out-of-plane torsion appeared in the precast specimens due to the influence of horizontal grouting joint.