拉索损伤下的斜拉桥状态分析和损伤识别

以某在建双排单索面三塔四跨斜拉桥为工程背景,利用有限元软件Midas/Civil,通过静力分析的方法,研究不同长度、不同位置的拉索损伤对全桥索体索力、主梁线形变化的影响规律,为此桥将来健康监测设备的布设和构件的维修加固提供科学依据;通过引入曲率模态理论和灰色度相关理论,对测量信息不完备的结构系统进行拉索损伤识别方法的研究.研究结果表明,10号塔右侧和12号塔左侧拉索损伤时对结构内力的影响最大;当多根拉索同时发生损伤时,拉索的横向对称损伤对结构的影响最大,原点对称损伤影响最小,如若进行换索施工,建议采用原点对称的方式进行;提出了索力指标和曲率位移指标的双指标损伤识别方法,并在结构系统信息不完备的情况下成功实现了损伤拉索的定位,且该方法比基于单参数损伤识别的结果更加准确.

Condition Analysis and damage Identification for Cable Damage of Cable-stayed Bridge

For an exhaustive account of the application of Midas/Civil and the method of static analysis in the investigation of the change rules of cable force and girder geometry under the cable damage of different lengths and positions, a cable-stayed bridge under construction with incomplete measurement information, which has 2 row 1 cable faces and 3 towers and 4 spans, was taken as an example. In terms of the cable damage identification for structural systems with incomplete measurement information, the curvature modal theory and grey degree correlation theory were introduced in this case. The results show that the damage of the cable on the right side of Tower 10 and the left side of Tower 12 had the greatest impact on the internal forces of the structure. When multiple cables are damaged at the same time, the transverse symmetric damage of the cables has the greatest impact on the structure, and the origin symmetry damage has the least impact. That is to say, it is suggested to adopt the method of origin symmetry for cable replacement. Moreover, a two-parameter method of damage identification based on both cable force index and curvature displacement index was presented, and it was successfully proved to be applied in the actual example.