基于桥梁挠度监测的斜拉桥拉索损伤识别研究

Research on Cable Damage Identification of the Cable-stayed Bridge Based on Bridge Deflection Monitoring

斜拉桥是公路建设中常见的大型结构,被广泛应用于沟壑、河流等复杂地形环境。斜拉桥在长周期运营下极易出现自然环境、突发事故,导致损伤,直接表现为斜拉桥主梁挠度、拉索索力产生剧烈变化,最终引发结构强度丧失。文章依托湖南省某曲线双塔三跨斜拉桥工程,构建Midas Civil三维空间模型,对单索在不同程度损伤下(折减面积11.1%、33.3%、77.8%)的拉索索力、梁体挠度变化进行分析。研究结果表明,相对于无损伤状态,主梁锚固点处挠度随着拉索损伤程度的加剧而增大;损伤程度一致时,主跨锚固点处挠度变化大于边跨,且边跨锚固点处挠度变化分布要比主跨分布更明显。

The cable-stayed bridge is a common large structure in highway construction,and is widely used in complex terrain environments such as gullies and rivers.It is prone to damages caused by natural environment and sudden accidents under long-term operation,which is directly manifested as dramatic changes in the main beam deflection and the cable force of the cable-stayed bridge,and finally leading to the loss of structural strength.Based on a curved double-tower three-span cable-stayed bridge project in Hunan Province,the Midas Civil 3D spatial model is constructed to analyze the changes of cable force and beam deflection of single cable under different degrees of damage(reduction area 11.1%,33.3%,77.8%).The results show that the deflection at the anchorage point of the main beam increases with the cable damage degree increase compared with the non-damage state. When the damage degree is consistent, the deflection change at the anchorage point of the main span is greater than that of the side span, and the deflection change distribution at the anchorage point of the side span is more obvious than that of the main span.