黑龙江呼兰河大桥的光纤光栅智能监测技术

对光纤光栅波长变化与应变的关系进行了理论分析,并通过材料试验和等强度梁试验加以验证;研究了光纤光栅的布设工艺,并在黑龙江省呼兰河大桥预应力箱形梁的施工过程中成功地布设了12个光纤光栅应变传感器与3个温度传感器;布设的传感器监测了预应力箱形梁张拉过程的钢筋应变历程,以及箱形梁静载试验的钢筋应变增量与分布;大桥建成后,利用布设的光纤光栅应变和温度传感器对呼兰河大桥进行了阶段性运营监测,监测了车辆荷载下的应变历程和大桥温度变化过程。监测结果表明埋入的光纤光栅可以方便地监测汽车的流量及其可能的疲劳损伤,为桥梁结构的健康诊断提供依据。一年多的考验表明,光纤光栅的稳定性与耐久性满足钢筋混凝土桥梁结构长期健康监测的要求,性能明显优于传统的电阻应变片。

INTELLIGENT MONITORING OF HEILONGJIANG HULAN RIVER BRHDGE BASED ON FBGS

The relationship between FBG's Wavelength change and Strain has been studied theoretically and testified by testing of material and equal strength beam. Techniques of installation of FBGs have been explored, and 12 strain sensors and 3 temperature sensors have been successfully installed on the prestressed box girder during the construction of Heilongjiang Hu-lan River Bridge. Strain of the reinforced steel bars has been monitored during the course of prestress tension with the FBG stain sensors in the box girder, and the stain increments and distribution have also been monitored when the box girder under dead load with these sensors. After the bridge finished, the FBG sensors monitored the strain course under traffic load and temperature changes of the bridge. The monitoring results show that traffic fluxes and possible fatigue damages can be monitored conveniently by embedded FBG sensors, and information can be provided for structural health diagnosis. That the FBG stain sensors have withstood the ordeal for more than one year proves that their durability and stability satisfies the need of health monitoring for bridges, and FBG strain sensor is more adaptive to long-term structural health monitoring than the electric strain gauge.