预应力连接预制节段桥墩拟静力试验数值仿真分析

NUMERICAL SIMULATION ANALYSES ON QUASI-STASTIC TESTS OF PRECAST SEGMENTAL PRESTRESSED BRIDGE COLUMNS

预应力连接预制节段桥墩已在美国低震区桥梁中得到较多应用,但在我国的工程应用甚少。由于预制节段桥墩的震害资料缺乏,震害经验不足,且其抗震机理不明确、设计方法不完善,在强震区较少应用。该文基于预应力连接预制节段墩柱缩尺模型的拟静力往复试验测试,采用有限元分析软件ABAQUS建立其精细化数值模型,进行了单向、斜向往复荷载作用下墩柱拟静力试验数值仿真,将桥墩的损伤特征、滞回行为、墩内竖向预应力和预制节段间接缝开口量与试验测试结果进行了对比分析。结果表明:该文建立的预制节段桥墩数值模型可较好地再现拟静力试验结果,试验和模拟结果均表明斜向加载的预制节段墩柱较单向加载的构件损伤更为严重,构件屈服更早,残余位移较大,墩柱最大偏移率达4%时其残余偏移率已超过1%。常规设计中桥墩按纵桥向或横桥向单向抗震设计偏于不保守,特别是考虑震后功能可恢复或可修复时建议考虑多向地震作用影响。

Precast segmental prestressed columns have been widely applied in low seismicity regions in United States,but there are few applications in China.Due to the lack of seismic damage data,to the insufficient knowledge of their seismic performance and to the imperfect design method,the application in high seismicity regions is limited.According to the existing quasi-static test of a scale precast segmental prestressed column,a numerical model for the precast column under unidirectional and diagonal cyclic loads was developed by software ABAQUS,and its nonlinear behavior was verified by the experimental results.The local damage,hysteresis behavior,prestress force and joint opening of the model were compared and analyzed with the experimental results.The research results show that:the results of the model are in a good agreement with the experimental results.Both the test and simulation results show that the column under diagonal cyclic loading has more serious concrete damage,smaller yield displacement and lager residual displacement compared with the column under unidirectional cyclic loading.The residual drift has exceeded 1%when the maximum drift of the column is 4%.Therefore,only considering the unidirectional load can be non-conservative in the seismic design of precast segmental columns,it is recommended to consider the influence of multidirectional seismic loads especially when considering that the columns can be restored or repaired after earthquakes.