【作者】 肖明洋；

【导师】 李乔；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2013， 硕士

【摘要】 桥梁结构的地震易损性曲线揭示了桥梁损伤概率与地面运动强度之间的关系,它对震后响应计划、工程抢修、经济损失估计以及震后交通系统的功能评估等有重要的意义。高墩混凝土连续刚构桥是一种非规则桥梁,在一些地震易发地区的主干线上被广泛采用,其地震易损性的研究具有重要的意义。本文主要完成了以下几方面的工作：1、对桥梁抗震性能评估和桥梁地震易损性分析的流程进行了梳理,系统归纳了理论地震易损性分析中最重要的几个步骤,如地震波的选择和处理、损伤指标的选择、有限元分析方法、易损性曲线绘制方法等。2、研究了高墩混凝土连续刚构桥高阶模态和动轴力效应等地震力学行为。结合震害调查和理论计算确定了主墩和过渡墩支座为该桥在地震作用下的易损损伤位置,提出了一种可以考虑动轴力效应对桥墩延性影响的曲率损伤指标以评定主墩在地震中的损伤程度。3、对比了谱加速度和地面峰值加速度这两种地面运动强度指标对高墩混凝土连续刚构桥地震易损性分析的适用性,结果表明采用谱加速度分析的结果具有更小的离散性,更适合这类较长周期结构的地震易损性分析。4、对主墩进行了地震易损性分析,并绘制了地震易损性曲线。结果表明：主墩具有良好的抗震性能；在纵桥向地震作用下墩底相对于墩顶更易损,但差距不明显；主墩在进入严重破坏状态后,可能会随着地震强度增大迅速进入完全破坏状态；墩底在横桥向地震作用下相对于纵桥向表现得更易损。5、采用位移损伤指标对过渡墩支座进行地震易损性分析,并绘制了地震易损性曲线,结果表明：在不考虑支座横向限位装置和抗震挡块的情况下,支座在横桥向的地震作用下比纵桥向损伤概率更高,且这种差异十分明显；支座很可能在整体结构尚未进入强非线性阶段就已经损坏。6、初步探讨了采用裂缝宽度指标评定钢筋混凝土桥墩的地震损伤的方法,并进行了实力分析,得出主要结论和采用曲率指标接近。更多还原

【Abstract】 Seismic fragility curve of the bridge structure reveals the relationship between the damage probability of bridges and ground motion intensity; it is very important for the response plan after the earthquake, engineering repairs, estimating economic loss and performance assessment of transport systems in the post-earthquake. Concrete continuous rigid bridge with high piers is a kind of irregular bridge, and it is widely used in some trunk lines of the earthquake-prone areas. Its seismic vulnerability study is of great significance. The following work has been done in this thesis:(1) The process of the bridge seismic vulnerability analysis is sorted and the most important steps of the analysis of seismic vulnerability such as the selection and processing of seismic waves, the damage index selection, finite element analysis methods and the plotting methods of the vulnerability curve are systematically summarizes.(2) Seismic mechanical behavior of concrete continuous rigid bridge with high piers such as higher order modes effect and dynamic axial force effect are researched. The main piers and bearings of the transition piers are selected as the most vulnerable location under the earthquake according to both the damage investigations and theoretical calculations. A curvature damage index with the dynamic axial force effect considered is proposed to assess the damage degree of main piers under earthquake.(3) The spectral acceleration and peak ground acceleration are compared as ground motion intensity indicators used in the seismic fragility analysis of the concrete continuous rigid bridge with high piers. The results show that the results with spectral acceleration as ground motion indicator have smaller discrete, so it is more suitable for the seismic fragility analysis of the structures with longer period.(4) Seismic fragility analysis of the main pier has been performed, and the seismic vulnerability curves have been plotted. The results show that:the main piers have good seismic performance; the bottoms of the piers are more vulnerable than the top under the earthquake of the longitudinal direction of the bridge, but the difference is minor; Main Pier under serious damage state will quickly go to the complete damage state as the intensity of ground motion increased; the bottoms of main piers are more vulnerable under the earthquake of the transverse direction of the bridge than the longitudinal one.(5) Displacement damage index is used to perform the seismic vulnerability analysis of the transverse piers bearings and seismic fragility curves are also plotted. The results showed that:bearings are vulnerable under the earthquake of the transverse direction of the bridge than the longitudinal one if the devices which restrain the lateral displacement of the bearings and the anti-knock block are ignored, and this difference is obvious; bearings may have been damaged before the overall structure entered the strongly nonlinear stage.(6) The method of damage degree assessment of the reinforced concrete bridge piers under earthquake as the crack width with damage index, and example has been given. The main conclusions are close to which get from a curvature index as damage index.更多还原