Bridges serve as an important component of transportation infrastructure and deflection is one of the most significant technical parameter reflecting the structural performance of the bridges. A laser projection method was chosen from similar research and technology to measure the bridge deflection, thus breaking through the problems of developing a point source laser with proper function-to-price ratio and expanding the measuring range of the light target. As a result, the collimation laser projection sensing technology has been devised, which an effective measurement in the bridge deflection is monitoring, especially for the larger ones. In this paper, a practical application in Tukan Wujiang Bridge with the technology is designed and installed. The measurement results (from 2010.1 to 2010. 6 ) of the collimation laser projection method show that the largest deflection of the bridse during the monitored period is not more than 2 cm. Hence, the bridge is working well. The system has always been good in operation and accuracy from the installation since 2008, and it has implemented the bridge deflection online monitoring.%桥梁是交通基础设施中的重要组成部分,而桥梁挠度则是反映桥梁结构性能最为重要的技术参数之一.从国内外同类研究、同类技术中可实现桥梁结构挠度长期健康监测的方法中选择激光图像法,对其现有技术上所遇到的开发性价比合适的高质量点光源激光器和如何适当扩大光接受芯片标靶的测量范围两方面的难题进行了突破.研发了准直点激光投射式挠度监测方法,该方法是精确测量特别是大跨径桥梁挠度变化的一种有效方法.本文设计并成功安装了土坎乌江大桥准直点激光投射式挠度监测系统,并对该桥近期(2010.1～2010.6)监测数据进行分析,结果显示结构最大挠度在2cm以内,桥梁运行状况良好.该系统从08年安装至今一直运行正常,系统稳定性较好,实现了桥梁结构挠度的在线监测.
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