桥梁墩柱抗震能力及影响因素对比研究

Comparative Research on Anti-seismic Capability and Its Influencing Factors of Bridge Columns

针对典型梁桥墩柱的抗震能力及其影响因素展开对比研究。根据材料非线性本构关系建立墩柱塑性铰区截面的弯矩-曲率关系,分析轴压比、纵筋率、配箍率等对墩柱抗弯能力和延性的影响。基于AASHTO、CALTRANS、ATC-32、抗震细则等规范对墩柱的抗剪能力、塑性铰转动能力进行对比研究。结果表明:增大轴压比和纵筋率均可提高墩柱的抗弯能力,但都会降低墩柱的延性;提高配箍率可有效地增强墩柱的抗弯能力和延性,但增幅随配箍率的提高而趋缓;抗震细则中有关墩柱抗剪和转动能力的公式过于保守,普遍远低于其他规范的计算值。

In this paper,the anti- seismic capacity and its influencing factors are investigated for the typical bridge columns. The nonlinear constitutive relationships of materials are used to establish the moment- curvature relationships of the column plastic hinge region. Effects of axial compression ratio,longitudinal reinforcement ratio,and transverse reinforcement ratio are examined on the flexural capacity and ductility of the column. Following the codes of AASHTO,CALTRANS,ATC- 32 and guidelines for seismic design of highway bridges,the shearing resistance capacity and the rotational capacity of the plastic hinge are compared for the column. The results show that the increase of axial compression ratio and longitudinal reinforcement ratio will increase the flexural capacity of the column,but will decrease the column ductility. Increase of the transverse reinforcement ratio can effectively increase the flexural capacity and the ductility of the column,and the increase is getting slower while the transverse reinforcement ratio is reaching higher. The method provided in the guidelines for seismic design of highway bridges for calculating the shear resistance capacity and the rotational capacity of the column is shown to be too conservative,whose calculation values are much lower than those of other codes.