预制拼装桥墩地震易损性分析

为研究灌浆波纹管连接和带榫头的灌浆波纹管连接两种预制拼装桥墩的抗震性能并对其在地震作用下的易损性进行评估，根据预制拼装桥墩墩底接缝的特点，通过拟静力试验研究，以墩顶漂移率为损伤指标，对其不同的损伤破坏状态进行描述，并确定了对应不同破坏等级的损伤量化指标限值Dcr、Dcy、Dcm和Dcu。采用有限元软件对现浇及预制拼装桥墩进行不同地震作用下的时程分析并建立概率地震需求模型，对其易损性进行评估，并通过改变轴压比、纵筋配筋率，来进一步研究这些参数对预制拼装桥墩易损性的影响。结果表明：虽然预制拼装桥墩与现浇桥墩大部分的破坏形式都为弯曲破坏，但是损伤状态因为接缝而存在差异；采用波纹管连接的预制拼装桥墩与现浇桥墩的地震易损性差别不大，抗震性能基本一致；有榫头构造的预制拼装桥墩在各级地震作用下发生四种损伤破坏的概率最低，这种构造形式的抗震性能优于平面接缝的预制拼装桥墩；轴压比、纵筋配筋率这两种参数对桥墩的易损性影响较大，随着轴压比的增大或配筋率的减小，桥墩的损伤概率增大。

Seismic vulnerability analysis of precast segmental bridge piers

To investigate the seismic performance of precast segmental bridge piers with column-to-footing connection using grouted corrugated duct with and without mortise-tenon and evaluate their vulnerability under earthquake, the damage states of a cast-in-place pier and two precast piers are studied by quasi-static tests according to the characteristics of the joints at the bottom of precast segmental bridge piers. In these tests, the drift ratio of the pier top is taken as the damage index to describe the damage state, and the quantified damage index limits Dcr、Dcy、Dcm and Dcu are determined for different damage levels. The finite element software is used to analyze the time history responses of cast-in-place and precast bridge piers under different earthquake intensities, and the probabilistic seismic demand model is established to evaluate their vulnerability. The influences of parameters including the axial compression ratio and longitudinal reinforcement ratio on the vulnerability of precast segmental bridge piers are further studied. Although most of the failure modes of precast and cast-in-place piers are bending failure, the damage states differ due to the connection type; the seismic vulnerability of precast pier with grouted corrugated duct connection is not evidently different from that of cast-in-place pier, and moreover their seismic performance is basically the same; for precast segmental bridge pier with mortise-tenon joint, the occurrence probabilities of four kinds of damage levels are the smallest under different levels of earthquake actions. With the increase of axial compression ratio or the decrease of reinforcement ratio, the damage probability of pier tends to increase.