桥梁内部预应力钢绞线应变的长久监测与分析

重点研究应用埋入式光纤光栅传感器对正在施工中桥梁的预应力钢绞线应变进行跟踪监测的测试方法，分析温度、横向应变等多种因素对测量结果有效性的影响，同时考察了预应力钢绞线在复杂施工环境中的力学行为．研究发现在温度变化较大时应该对测量结果进行温度补偿，同时在非均匀横向应变场作用下光纤光栅不再遵循布拉格条件，对此应做进一步的研究分析，试验结果表明光纤光栅传感器具有易埋入、抗干扰能力强、可对应变进行绝对测量等优点，非常适合于结构内部健康的长期监测。

Long Monitoring and Analysis on the Strain of Prestressed Twist Steel Cables Inside a Bridge

The method of monitoring the strain of prestressed twist steel cables under construction by means of embedded optical fiber Bragg grating sensor (FBGS) was studied,and the influence of temperature,transverse strain and other factors on the effectiveness of measurement results were analyzed. The mechanics behavior of the prestressed twist steel cables in the complicated constructing environment was probed. It shows that if the temperature changes greatly,the measurement results should be compensated.And applied the non-uniform transverse strains,FBGS does not meet the Bragg rules and further study should be made. The test results show that the FBGS has the advantages of easy embedment,strong resistance to magnetism and absolute measurement of the strain,therefore it is a good sensor for long monitoring of the structural health inside structures.