悬索桥易损性分析与简化模型
Suspension Bridge Vulnerability Analysis and Simplified Model

对中国当前已建和在建的车行悬索桥进行了统计分析，总结其分类特点，得到了统计意义上桥梁主要参数间的关系，并利用线性拟合得到趋势拟合公式。选取3座典型悬索桥（双塔地锚式平行双索面桥、双塔自锚式平行双索面桥、独塔自锚式空间索面桥）建立有限元模型，对影响悬索桥振动的主要参数进行了敏感度分析；利用塔底弯矩曲率曲线确定不同等级的损伤指标，采用增量动力分析(IDA)法得到地震反应需求值，通过计算不同损伤指标的能力需求比，对悬索桥的易损性进行分析。针对震后灾害快速评估的需求，建立单塔简化模型来计算易损性曲线。结果表明：对算例桥梁而言，主塔顺桥向弯曲振动，主塔刚度对自锚式平行索面悬索桥影响大，主缆刚度对地锚式平行索面悬索桥影响大；横桥向主塔刚度对3座桥影响均较大；地锚式悬索桥比自锚式悬索桥易损，而自锚式悬索桥中双塔平行索面桥抗震性能优于独塔空间索面桥；单塔简化模型在一定程度上能够满足震害后快速评估的需求，误差基本在工程上可以接受的范围。
The statistical analysis of suspension bridges of vehicles that had been built and under construction in China was carried out, and the classification characteristics were summarized. The relationship between the main parameters of the bridges in the statistical sense was obtained, and the trend fitting formula was obtained by linear fitting. Three typical suspension bridges (double tower anchored parallel double cable plane bridge, double tower self-anchored parallel double cable plane bridge, single tower self-anchored space cable bridge) were selected to establish the finite element model, and the main parameters affecting the suspension bridge vibration sensitivity analysis was carried out. The damage index of different grades was determined by the bending moment curve of the tower bottom. The seismic response demand value was obtained by incremental dynamic analysis (IDA) method. The vulnerability of the suspension bridge was analyzed by calculating the capacity demand ratio of different damage indicators. Aiming at the need for rapid assessment of post-earthquake disasters, a simplified model of single tower was established to calculate the vulnerability curve. The results show that, for the bridges in the example, the main tower stiffness has great influence on the self-anchored parallel cable？？stayed suspension bridge, and the main cable stiffness has great influence on the ground？？anchored parallel cable-stayed suspension bridge. The stiffness of the main tower has great influence on the three types of bridges; the ground anchored suspension bridge is more vulnerable than the self-anchored suspension bridge, and the seismic performance of the double tower parallel cable bridge in the self？？anchored suspension bridge is better than that of the single tower space cable bridge. The model can meet the needs of rapid assessment to a certain extent, and the error is basically acceptable in engineering