高架桥钢轨伸缩调节器的光纤光栅监测技术

FBG Monitoring Technology on Urban Railway Expansion Device of Elevated Bridge

城轨连续梁高架桥梁缝和钢轨伸缩调节器的轨温、钢轨位移、梁体位移、钢轨和尖轨应变监测采用了光纤光栅传感技术。通过监测,使运营和管理部门掌握桥梁和钢轨在长期运行过程中结构的变化规律,以确保城轨的运行安全。应变检测采用预制的光栅应变片;位移检测采用受力环的光栅位移传感器;温度检测采用管状光栅温度传感器。参考光栅的应用抵消了环境温度变化产生的影响。全部光纤光栅悬空粘贴,避免了布喇格反射峰的啁啾化,提高了检测精度。几种传感器经历了冷热气候的检验,监测结果与手测值以及理论计算值相吻合。

Fiber Bragg Grating （FBG） sensing technology was used to monitor the operating condition of rail expansion devices in an elevated bridge, including rail temperature, rail displacement, crevice displacement of continuous beam joint, and stress of sliding rails near the expansion devices. By monitoring these data, the operators could know the chan-ging regularity of rails on elevated bridges in long-term operation, and could therefore ensure safety. In this monitoring system, strain sensor was a prefabricate FBG strain gauge; displacement sensor with different scale used an FBG stress ring; and FBG temperature sensor was pre-drawn and fixed in a metal tube. Referenced FBGs were used to offset envi-ronmental temperature interference. The FBG part of all FBGs was suspended and adhered only at its ends. The chirped phenomenon of FBG reflection peak was therefore avoided and measurement accuracy was improved. All kinds of sensors experienced cold and hot seasons. The monitoring results match to the manual check and theoretical estimate.