基于应变差值类影响线的桁架损伤识别

Damage Detection in truss Using Strain Difference Influence Lines

面向基于静力测试数据的结构损伤识别问题,发展一种基于应变差值类影响线来识别损伤的方法,该方法利用事先规定应变测量单元的桥梁结构在单位移动荷载作用下的应变影响线,通过差值、求导计算,提出以应变差值、一阶导和二阶导影响线作为损伤指标的损伤诊断方法,一点测量多点激励,直接对所得影响线图进行观察即可准确定位损伤。本文分别以钢桁梁桥和星海跨海悬索大桥主桁架简化模型为例,分析了距离损伤杆远近不同的腹杆做测点识别损伤的效果,结果表明:该方法可以有效识别桁架腹杆损伤。

Aiming at the structural damage detection based on the static test data,a method of damage recognition based on the strain difference influence lines is developed. The strain influence lines on the pre-defined strain measurement elements of the bridge component under the unit moving load is utilized to carry out the difference and derivation calculation,thus the damage diagnosis method based on strain difference,first order and second order influence lines as damage index is put forward,achieving a little measure of multi-point excitation. The difference influence lines graph is observed directly to locate the damage. Taking the simplified model of the main truss of the steel truss girder bridge and the Xinghai sea bridge as an example,the effect of detecting the damage of the abdomen with different distance from the injured rod is analyzed. The results were shown that this method can effectively identify the truss damage.