采用8节点实体单元模拟主塔和桥墩,考虑塔、墩的剪切变形和初应力对结构刚度的影响,建立了猎德大桥精细化有限元模型.进行了缩尺比为1:60的全桥模型振动台试验,比较了试验和仿真计算结果.在此基础上,研究了实桥的地震响应特征,并对构件的抗震能力进行了评价.研究结果表明:塔根截面、群桩桩顶是结构抗震的关键部位;考虑承台-土压力的影响时,群桩基础的应力可降低13%~25%;精细化有限元模型较好地反映了结构在地震作用下的易损部位.
The tower and piers were simulated with 8-nodes solid element. The elaborated finite element model of Liede bridge was established by taking the changes of structural stiffness influenced by initial stress and shearing deformation into consideration. A full three-dimensional model in a proportion of 1 : 60 was tested on a shaking table and a comparison was made between the calcualted results and the measured data. Then seismic response characteristic of the real bridge was studied and the anti- seismic ability of the construction members was assessed. Results show that the stress level of the bottom of tower and the top of pile groups is highest. The stress of pile foundation can be reduced by 13% to 25 % if the interaction between pile-support and soil is considered. The vulnerable part of a bridge can be judged by elaborating the finite element model.