预应力筋长期大应变测量的光栅传感技术研究

Research on the FBG Sensing Technology for Long-term Measuring of the Large Strain of Prestressed Reinforcement

预应力筋是预应力钢筋混凝土结构中的关键受力构件,其预张拉应变为6 000-7 000με,远大于通常结构的应变范围。为解决预应力筋的长期大应变测量问题,提出了螺旋倾斜光栅传感元的复合技术,首次建立了光栅实测应变与被测体真实应变间的理论关系模型,并进行了试验验证。研究结果表明,该方法不仅可有效降低光栅的拉应力水平、确保其长期安全可靠性,且通过控制倾角在一定范围内同样可满足工程实际中的应变分辨率要求,为解决预应力筋大应变状态下的长期安全监测和评价问题奠定了重要的理论和实践基础。

The prestressed reinforcement is the key component to bear loads in prestressed concrete structure.The pre-tensile strain of the prestressed reinforcement can reach 6 000 με to 7 000 με,which greatly exceeds the range of ordinary structures＇ strain.In order to resolve the problem of long-term measuring for large strain of prestressed reinforcement,the technology of bonding FBG spirally and slantingly was proposed.The theory relationship model between the measured strain of FBG and the actual strain of measured structure was established for the first time,and the proving tests were also carried out.The results shows that the method not only can effectively reduce the tensile stress of FBG and ensure its long-term security and reliability,but also can satisfy the strain resolution required in practical engineering.The researches have established the theoretical and practical foundations for the long-term monitoring and estimation of prestressed reinforcement in large strain.