地震工程学报2017，Vol.39Issue(1)：13-19,79,8.DOI:10.3969/j.issn.1013-0019.2017.01.0013
考虑冲刷作用效应桥梁桩基地震易损性分析
Seismic Fragility Analysis of Bridge Pile Foundation Considering Scour Effect
摘要
Abstract
The erosion of soil by scour around a pile weakens the lateral support in bridge founda-tions and this phenomenon has an effect on the seismic vulnerability of bridge pile foundations. Therefore,it is important to study the seismic fragility of bridge piles in the presence of scour. We used SAP2000 software to establish a three-dimensional finite element bridge model in the presence of scour.Damage occurs more readily at bridge piers and pile foundations and these com-ponents may become plastic during earthquakes.As such,we simulated these components using an elasto-plastic connection unit.We simulated the mechanical behavior of the soil using nonlinear p-y springs and modeled the loss of soil by removing the p-y springs above the scour surface.We selected 80 acceleration time histories of seismic waves that conformed to site II,and then trans-lated the acceleration time history of each seismic wave into the displacement time history.We then applied the displacement time history to the p-y springs and carried out a nonlinear time history analysis on the bridge model.We obtained the seismic response of the bridge and recordedthe maximum response of the bridge pile under each seismic wave.Using a probabilistic seismic demand analysis approach,we developed an analytical seismic vulnerability model of the bridge pile at different scour depths.We used curvature ductility as a damage index,and according to Hwang's suggestion,defined different damage states of the pile foundation.We obtained the boundaries of damage states by applying moment-curvature analysis to the pile cross section,thus obtaining quantitative data of the different damage states of the pile foundation.On this basis,we assumed that lognormal distribution functions were suitable for developing fragility functions, and we used regression analysis to estimate the parameters in the seismic fragility functions.We established the seismic fragility curves of the pile under different scour depths, and then discussed the influence of scour depth on the probability of the pile damage.The results show that with increasing scour depth,the probability of seismic damage to bridge pile foundations increa-ses.Therefore,special attention should be paid to the adverse influence of scour when designing earthquake-resistant bridge pile foundations.关键词
冲刷效应/地震/共同作用/桩基/地震易损性曲线Key words
scour effect/earthquake/combined action/pile foundation/seismic fragility curve分类
交通工程引用本文复制引用
梁发云,刘兵,李静茹..考虑冲刷作用效应桥梁桩基地震易损性分析[J].地震工程学报,2017,39(1):13-19,79,8.基金项目
国家自然科学基金重大研究计划集成项目(91315301-05) （91315301-05）
中央高校基金科研业务费专项资金 （）
