为了研究水平双向地震作用下矩形空心桥墩的抗震性能,对约束良好但轴压比和纵向、横向配筋率不同的5个钢筋混凝土(RC)矩形空心桥墩在轴力和双向弯曲作用下的性能进行了循环试验研究。结果表明:试件破坏形态为桥墩底部形成塑性铰的弯曲形破坏,桥墩双向力-位移滞回曲线显示了双向压弯状态下RC矩形空心桥墩刚度和强度退化、捏拢效应以及2个水平方向抗震性能的相互影响;试件桥墩的延性系数在3.5~5.7之间,等效粘滞阻尼系数在0.19~0.26之间,延性系数和耗能指标均满足结构抗震设计要求;所给出的横向配筋构型的RC矩形空心桥墩在水平双向地震作用下具有良好的抗震性能,可以取代中国规范JTG/T B02-01—2008中建议的矩形空心截面横向配筋构型;桥墩塑性铰区域高度约为桥墩高度的1/6,远小于规范规定的塑性铰长度的最小值,空心截面桥墩塑性铰发展区域更为集中。
To investigate the seismic performance of reinforced concrete (RC) rectangular hollow bridge piers, cyclic testing on five well-confined specimens was performed under constant axialload and biaxial bending. The test variables included axial load ratio, longitudinal reinforcement ratio and lateral reinforcement ratio. The results show that these specimens are flexural failuremodes; biaxial force and displacement hysteretic loops show significant stiffness and strength degradation, pinching effect and coupling interaction of the structural seismic resistances in bothdirections; the ductility Coefficient, varying from 3.5 to 5.7, and the equivalent viscous damping ratio, varying from 0.19 to 0.26, can meet the requirements of seismic design; RC rectangularhollow bridge piers with configurations of lateral reinforcement subject to bi-directional earthquake components have excellent earthquake resistance, and can substitute for currenthollow RC rectangular section configurations described in the Chinese Guideline for Seismic Design of Highway Bridges (JTG/T B02-01-2008) ; and the length of the plastic hinge regionis found to approach one sixth of the the hollow RC rectangular bridge pier height for all specimenpiers, which is far less than the currently specified minimum value in Chinese Guideline, so the length of plastic hinge region is more concentrated for RC rectangular hollow bridge piers.