爬移状态对服役曲线梁桥抗震性能影响分析

Influence of creeping state on the seismic performance of curved girder bridges in service

摘要:

服役曲线梁桥常存在爬移病害。为探讨爬移病害程度对曲线梁桥抗震性能的影响规律,通过总结服役曲线梁桥爬移病害,确定以不同梁端爬移位移量作为描述服役曲线梁桥爬移状态的对比分析工况,并以一座三跨预应力混凝土曲线梁桥为例,采用MIDAS Civil建立有限元模型,考虑桩-土相互作用、双向碰撞效应及材料非线性,分析曲线梁桥支座及桥墩等主要受力构件地震响应规律,探讨爬移状态对服役曲线梁桥抗震性能影响。研究结果表明:主梁的爬移病害对桥梁的抗震性能会产生不利影响,会导致支座位移的增长,增加支座破坏的风险,从而增加桥梁上部结构碰撞效应及落梁风险;随着爬移位移的增加,桥墩的损伤状态可能由爬移前的无损伤转变为考虑爬移后的严重损伤状态。因此,在进行服役曲线梁桥抗震性能评估时应量化其爬移状态,并采用合理的措施对主梁的爬移进行限制。

Abstract:

Creeping diseases often occur in curved girder bridges in service. To explore the influence of creeping disease on the seismic performance of curved girder bridges, we summarized creeping diseases and used various creeping displacements at the girder end as comparative analysis conditions. A three-span prestressed concrete curved girder bridge was used as an example, and the finite element model was established using MIDAS Civil. The effects of pile-soil interaction, bidirectional pounding effect, and material nonlinearity were considered in the analysis of seismic responses of the main members of the curved girder bridge, such as bearings and piers, and the influence of the creeping state on the seismic performance of the bridge was discussed. The results show the adverse effect of creeping diseases of the main girder on the seismic performance of the bridge, leading to the expansion of bearing displacement and increased risk of bearing damage. As a result, the pounding effect of the bridge superstructure and the risk of beam falling increased. With the increase in creeping displacement, the damage state of the bridge pier may change from no damage without considering creeping to a serious damage state when creeping is considered. Therefore, the evaluation of the seismic performance of curved girder bridges in service and creeping state should be quantified, and reasonable measures should be implemented to limit the main girder creep.