基于斜拉索张力测定的斜拉桥健康诊断

应用试验校正的高精度三维有限元模型,对斜拉桥主梁结构损伤位置识别的斜拉索张力指标进行了研究。模拟12种可能的损伤情况,研究了基于斜拉索局部模态基频构造索张力指标的方法,索张力指标对各损伤情况下损伤位置的识别效果和对损伤程度的敏感性。结果表明,用斜拉索局部模态基频所构造的张力指标对不同的损伤程度呈现较好的稳定性和灵敏性,对模拟的12种损伤情况的正确识别率可达75%。该方法的突出优点是只需测量斜拉索局部振动模态的基频,就能获得较好的损伤识别效果,比其他面向损伤检测的测量容易得多。该方法可十分方便地推广应用于悬索桥加劲梁结构的损伤定位,具有较高的实用价值。

Damage Locating for Cable-stayed Bridge Based on Stay Cable Tension Measurement

Stay cable tension index for damage localization on main girder of cable-stayed bridge was studied based on a precise and validated three-dimensional finite element model.A series of damage cases associated with the bridge deck were introduced in the simulation study.The simulation study was conducted with the following focuses:(1)construction of the stay cable tension index based upon the fundamental natural frequencies of local modes of stay cables;(2) performance of the index in localizing the damage on the bridge deck;and(3) sensitivity of the index to damage extent for different damage cases.The analysis results show that stay cable tension index is quite stable and sensitive to damage extent for different damage types and 75% of the damage cases simulated can be identified correctly.The outstanding feature of the method is that a good result can be obtained by using only fundamental natural frequencies of stay cables.The method is much easier than any other damage-oriented measurement,it can be easily used for damage locating of cable suspension bridges.