盆式橡胶支座连续梁桥抗震性能优化设计研究

Study of Optimal Design of Seismic Performance of Continuous Beam Bridge Used with Rubber Pot Bearings

为研究盆式橡胶支座连续梁桥的抗震性能,采用有限元法分析连续梁桥的约束方式、一联跨数及跨度等主要参数对桥梁地震响应的影响。结果表明:常规的纵向单墩固定的约束形式一般不能满足抗震要求,需采用中间多墩纵向约束,为保证桥墩的延性,需要适当增加固定支座下墩柱的配箍率;支座约束方向的水平承载力要求较高,需设置抗震销、横向挡块等保险措施;一联跨数增加,对单个墩的地震响应影响不明显;减小跨度,上部结构质量减小,地震反应减小明显。

To study the seismic performance of continuous beam bridge used with pot rubber bearings, the finite element method was adopted to analyze the influence of several main parame- ters, including the restraint modes, numbers of spans in one continuous unit and span length of continuous beam bridge, on the seismic response of the bridge itself. The results of the analysis indicate that the conventional longitudinal restraint mode of single pier fixity generally cannot meet the anti-seisrnic requirements while the longitudinal restraint of multiple piers in the middle of the bridge is needed. To ensure the ductility of the piers, the stirrup ratios in the pier columns beneath the fixed bearings should be properly increased and because of the higher demand of the horizontal bearing capacity in the restraint direction of the bearings, the safety measures like the arrangement of seismic pins and transverse stoppers are required. The increase of span numbers in a continuous unit does not have much influence on the seismic response of a single pier, hut when the span length and mass of the superstructure are reduced, the seismic response is apparently reduced.