表面式FBG应变传感器及其在高速公路桥梁工程中的应用

A novel surface-mounted FBG strain sensor and its application in highway bridge engineering

报道一种表面安装式光纤布喇格光栅(FBG)应变传感器及其在高速公路高架桥的车辆载荷压力试验中的应用。提出了一种具备应变放大能力且可调节的不锈钢封装的应变感测弹性结构,布设有FBG的弹性圆筒结构位于传感器中间部分,其横截面积小于传感器其他部分,传感器的应变测量放大系数可通过改变圆筒结构的长度和横截面积来调节。将24个经过测试标定后的应变传感器和6个FBG温度补偿传感器安装在甬台温高速吊水沿大桥箱梁底部,并对大桥实施一系列车辆载荷作用下的静态和动态试验,传感器表现出了良好的测量能力,3种静态载荷工况下的桥梁底部应变大小以及3种动态载荷工况下的应变变化情况被清晰地展现出来,理论分析与实验结果一致。

This paper describes the structural design, performance test and application of a surface-mount- ed FBG strain sensor for the load test of a highway bridge. A stainless steel packaged elastic structure with the capacity of strain sensitization and adjustment is proposed. An FBG is mounted in the cylinder located in the center section of the sensor. The cross sectional area of the center cylinder is smaller than that of other parts of the sensor. The magnification factor of strain t could be adjusted by changing the length and cross sectional area of the center cylinder,which is the basic principle of the sen- sitization. A reference test method is also designed for the calibration of the strain sensor. The strain measurement test results are consistent with the theoretical calculation. After each calibration test,24 FBG strain sensors and 6 FBG temperature compensation sensors are installed on the undersurface of box girder of Diao shui yan bridge in Yongtaiwen highway. The strain sensors demonstrate excellent measurement capability in a series of load tests. Strain responses of the strain sensors under three static working conditions and three dynamic working conditions are obtained effectively and plotted clearly, which demonstrate a more extensive application promising.