高桩承台桥梁概率洪水冲刷风险及时变抗震性能  

Probability flood scour hazard and time-dependent seismic performance of bridges with high-rise pile cap

作　　者：吴文朋 药永娇 吴志伟 肖洋椰 WU Wenpeng;YAO Yongjiao;WU Zhiwei;XIAO Yangye(College of Civil Engineering,Xiangtan University,Xiangtan 411105,China;Poly Changda Engineering Co.,Ltd.,Guangzhou 510620,China)

机构地区：[1]湘潭大学土木工程学院,湖南湘潭411105 [2]保利长大工程有限公司,广东广州510620

出　　处：《地震工程与工程振动》2023年第2期164-174,共11页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(51908481);湖南省教育厅科学研究项目(21B0148)。

摘　　要：位于地震活跃区的跨河流桥梁会面临地震和洪水冲刷两大自然灾害的威胁。为探讨高桩承台式桥墩的洪水冲刷风险以及冲刷对该类桥梁服役期间时变抗震性能的影响,以我国西部地区某跨河连续刚构桥为例,基于冲刷分量叠加法和概率分析方法,构建高桩承台式桥墩在不同年份洪水事件下的冲刷深度风险评估曲线;建立OpenSees桥梁有限元模型,通过不断更新模型中的p-y土弹簧来模拟洪水冲刷条件下的桩-土相互作用,研究洪水冲刷对高桩承台式桥梁动力特性和抗震性能的影响。研究结果表明:墩身分量对高桩承台式桥墩基础冲刷深度的影响很小,但承台分量和群桩分量对冲刷深度的影响较大;基础冲刷深度前10年增长较显著,随后增量开始减慢;随着基础冲刷年份增加,桥梁结构主要振型的周期、最大位移和墩顶截面最大内力均会逐渐增大,但墩底截面最大内力会减小;桩-土作用非线性效应会随基础冲刷深度增加而表现得愈加明显。The river-crossing bridges located in seismically active areas are threatened by the combined hazards of earthquake and flood-induced scour.To study the flood-induced scour risk of the bridge pier with high-rise pile cap and the effect of scour on time-dependent seismic performance of the bridge during the service life,a continuous rigid frame bridge across a river in western China was taken as an example.Based on the superposition of the scour components method and the probabilistic analysis method,the risk assessment curves of scour depth for the bridge pier with high-rise pile cap was developed for different years flood events.Then,the OpenSees finite element(FE)model was established and the constantly updated p-y spring elements were used to simulate the effect of flood-induced scour on soil-pile interaction.The effect of flood-induced scour on dynamic characteristics and seismic performance of the bridge with high-rise pile cap was analyzed.It is concluded that the pier stem component has little effect on scour depth of bridge pier with high-rise pile cap,but both the pile cap component and pile group component have much greater contribution to the scour depth computation.The scour depth of foundation increases significantly in the first 10 years and then the increment slows down.With the increase of foundation scouring years,the period of the main vibration modes of the bridge,the maximum displacements of different components and the maximum internal force of the pier top section will increase gradually.On the contrary,the maximum internal force of pier bottom section decreases accordingly.Meanwhile,the nonlinear effect of pile-soil interaction becomes more obvious with the increase of scour depth.

关 键 词：桥梁工程 地震 冲刷 概率性 风险分析 

分 类 号：U442.55[建筑科学—桥梁与隧道工程] TU462[交通运输工程—道路与铁道工程]