Abstract: To gain the online deflection data of box girder bridge,a novel Laser Video Deflection Displacement Measuring System (LVDMS) and a Non-contact Weighted-Stretched-Wire System (NWSWS) for measuring the deflection of a bridge are developed,according to the structural characteristics of box girder bridge.The constructions and principles of the two systems are explained,and performances,measurement precision and affecting factors are analyzed.The proposed systems can be used to monitor online data respectively to meet the different needs.Online deflection data of two box girder bridges of Yuqian Expressway are monitored.The deflection,in-box temperature and out-box temperature are measured online during the course of the experiment,and the plot of measured data is gained.The validity and coherence are analyzed from the trend line.Experimental results justify the utility of LVDMS and NWSWS.These two systems can be applied to the monitoring of real-world bridges.

Key words: box girder bridge, deflection, monitoring, LVDMS (Laser Video Deflection &, Displacement Measuring System), NWSWS (Non-contact Weighted-Stretched-Wire System)

摘要： 为获取箱粱桥实时挠度数据,根据箱梁桥结构特点,研究了新型激光视频挠度/位移测量系统(LVDMS)和非接触式张力线桥梁挠度测量系统(NWSWS),阐述两种系统的结构、原理,分析两种系统的性能、测量精度和影响因素。对不同测量需要的情况可分别采用两种系统进行在线监测。对渝黔高速公路上两座大型箱梁桥挠度变化进行了在线监测,在试验过程中对桥梁挠度、箱内温度和箱外温度数据进行同步测量,将各组测量数据绘成曲线。从其变化趋势分析两种测量系统的有效性和一致性。结果表明LVDMS和NWSWS能够达到桥梁挠度在线测量的性能要求,可以运用于桥梁的在线健康监测。

关键词: 箱梁桥, 挠度, 监测, 激光视频挠度/位移测量系统, 非接触式张力线桥梁挠度测量系统