基于地震易损性分析的平塘特大桥关键构件破坏顺序研究

Failure Sequence of Key Components of Pingtang Major Bridge Based on Seismic Vulnerability Analysis

为探究山区超高墩三塔大跨斜拉桥在地震作用下各关键构件(桥塔、支座、基础和桥墩)的破坏顺序,以在建的贵州平塘特大桥为工程依托,首先基于OPEENSEES软件建立空间有限元模型,然后基于概率理论建立斜拉桥地震易损性模型,最后以混凝土应变和支座相对位移为易损性指标进行增量动力分析,得到各构件易损性曲线,并基于各构件的易损性曲线对此类桥型的构件破坏顺序进行分析。研究表明:横向地震对该斜拉桥造成的破坏程度要大于纵向地震;在纵向地震作用下桥梁结构最易发生破坏的是中塔支座和边塔基础,在横向地震作用下桥梁结构最易发生破坏的是边塔支座和过渡墩基础。

This study explored the damage sequence of key components(pylon,support,foundation,and pier)of long-span three-pylon cable-stayed bridges with super-high piers in mountainous areas under earthquake action.The under-construction Pingtang major bridge in Guizhou province was taken as the case study.First,the spatial finite element model was established based on OPEENSEES software.Then,the seismic vulnerability model of cable-stayed bridges was established based on the probability theory.Finally,incremental dynamic analysis was carried out with concrete strain and relative displacement of support as vulnerability indicators.The vulnerability curves of components were obtained,and the failure order of components of this type of bridge was analyzed.The results showed that transverse earthquakes will cause more damage to the cable-stayed bridge than longitudinal earthquakes;the middle tower bearing and the side tower foundation in the bridge structure are most vulnerable to damage under longitudinal earthquakes;and the side tower bearing and the transition pier foundation in the bridge structure are most vulnerable to damage under transverse earthquakes.