Application Study On FBG Sensing Technology In Bridge Health Monitoring

Structural Health Monitoring (SHM) has been the focus of researchers all over the world. And FBG has become one of the most important sensing element in SHM due to its advantages such as high precision, high durabilities, quasi-distributive sensing, electric-magnetic resistance, small size, convenience to integrate sensing network, etc. With the economic development in China, investment in infrastructures is almost half of that in the whole world, which provides opportunities for SHM and also FBG sensing techniques. In this paper, some key techniques of practical applications of FBG sensors have been studied as followed.Firstly, an absolute temperature compensation technique has been brought forward. And its reliability and accuracy has been tested based on the data of long-term experiments.Secondly, in order to monitor the tress state of structures in service, a novel sensibility-enhanced installation and measurement technique of stress induced by dead load technique have been given And they are also tested by experiments Thirdly, cable load cell based on FBG sensor has been developed and applied in in Beijing Chaobai bridge.Besides, the accuracy, reliability and stability of FBG strain sensors have been valued by finite element analysis, experiments and practical applications.Finally, FBG monitoring system for Tianjin Yonghe Brige has been set up and it has been used to monitor the stress of cables, main beam and prestressed reinforcement .