R&D Of Several FBG Sensors For Practical Infrastructures And Their Applications

Along with the ceaseless calamities from infrastructures,"Structural Health Monitoring"has been the focus of the researches on disaster prevention and mitigation. The important core and prior conditions of "structural health monitoring" are high-qualified sensors that can detect the structure characteristics. FBG has caught the eyes of the researchers in the world due to its advantage, for example, absolute measure, moisture resistance, strong corrosion resistance, simple structure, good reliability, strong anti-interference and easy to constitute to spread the feeling network, etc. This is why FBG becomes the first choice of sensors for the structural health monitoring. In this paper, from the actual circumstance of the civil engineering, two kinds of FBG sensors have been developed. And the extreme performance of the sensors which were developed by our team was studied, at last they were applied in the structural health monitoring of bridge and big dam. The main work and results are following:Firstly, a prototype-packaged FBG strain sensor for steel rebar was developed with good properties of high durability, low cost and reliable. And its sensing properties under dead load have been tested. The experimental results show good feasibility and advantages of such kind of sensors for steel rebar strain measurement for practical civil infrastructures under harsh conditions.Secondly, a simultaneous load and displacement sensor based on FBG is designed. We have done some researches on the sensing properties of pressure and displacement through the experiments. The results show that the FBG sensor we have designed words well on measuring the pressure and the displacement of the structures simultaneity.Thirdly, the strain property of FRP strain sensors was studied under different temperature circumstances, so is fatigue property under circular load. The results show that FRP strain sensors can resistant high temperature and fatigue.Finally, the installation technique of FBG sensors was studied and then used in the health monitoring projects of Zhaobaoshan bridge and Zhougongzhai reservoir in Ningbo city. We monitored the strain change of the girder under the load of vehicles and part strain change while Zhougongzhai reservoir is in sluice.