用于预应力筋长期实时应力监测的光纤传感测试技术研究

Study on Optical Fiber Sensing Technology for Long-term Real-time Monitoring of Prestressed Reinforcement

预应力筋是预应力混凝土结构中的关键受力构件,对其应力状态的监测具有重大意义。针对传统测试方法难以有效解决其应力分布测试问题的现状,提出基于光纤布拉格光栅传感测试技术的预应力筋长期实时应力监测方法。设计模拟张拉装置,并构建预应力钢筋的光纤光栅应变测试系统,进行模拟试验研究,其试验结果表明,该测试系统适合于预应力筋的工作环境,具有线性度高、重复性好,且不影响基体性能的特点。此外,针对预应力钢绞线的特殊结构和工作特点,提出具有温度补偿能力的锚端光纤布拉格光栅应力传感测试方案,并进行理论分析。研究结果验证了光纤光栅传感技术用于预应力筋应力测试的可行性,并为其实际工程应用奠定了基础。

Prestressed reinforcement is the key compoonent to bear loads in prestressed concrete structure; its stress monitoring is significant. It is difficult to use connventional methods to monitor the distributed stress status of the prestressed reinforcement. A long-term real-time stress monitoring method of prestressed reinforcement based on optical fiber Bragg grating sensing teehnolngy was Propocsed. Simulated loading equipment was designed, and the optical fiber Bragg grating strain testing system far steel reinforcment was developed. The experimental results indicate that the test system is suitable far the ,working surroundings of steel reinfcrcement, and it has the characteristics of high linearity and good reproducibility, furthemore it has no influence on mechanical characteristics of steel reinforcemnent. Moreover, aiming at the special structure and working characters of steel strand, an optical sensing system, which has temperature compensation ability and located at anchor Position, was proposed and analyzed theoretically. The research results validate the feasibility of adopting fiber Bragg grating far the prestress test and establish the foundation far its practical application.