Study On Strain Sensors Based On FBG Applicated In Architectural Engineering

The paper discusses the applications of five FBG strain sensors. The project in the future will still conduct further research and analysis on the dynamic responses, the temperature sensitivity, improvement of range and accuracy. It will conduct a strain test on real construction of steel structure and concrete structure components by using these FBG strain sensors.In contemporary construction engineering, there exist a great deal of demands of strain detection. Due to its advantages, optical Fiber sensing technology has been gradually applied in the construction project to detect the strain of buildings, while optical Fiber Bragg Grating (FBG) sensing technology is most mature. It is of great practical importance to research on application of optical fiber strain sensor in construction engineering.This paper analyzes problems of optical fiber strain sensor which is mainly constituted of FBG strain sensor applied in construction engineering, concluding that capsulation form of FBG strain sensor affects strain sensing sensitivity; temperature interference FBG strain sensor; The chirp phenomenon of FBG strain sensor.With regard to the problems in the optical Fiber sensor applied in construction engineering, and with the advantages of new Fiber Reinforced Plastic, this paper proposes four kinds of improved sensor structure, designing and preparing different types of strain sensor in terms of capsulation, which are unilateral Carbon Fiber Reinforced Plastic(CFRP) capsulation; bilateral CFRP capsulation; unilateral Basalt Fiber R(?)inforced Plastic (BFRP) capsulation and bilateral BFRP capsulation FBG strain sensor. All three except unilateral CFRP-FBG strain sensor are barely mentioned in the existing literature and research.According to the existing chirp problem that always happens in application of FBG strain sensor in construction engineering, this paper puts forward an H-bracket FBG strain sensor framework structure, which is able to effectively transfer lateral strain into FBG axial tension and isolate the factors such as rough surface of measured structure or uneven strain by cracks, completely avoiding the chirp problem in FBG applications.This paper describes four kinds of FRP-FBG strain sensor structure in terms of structure properties, size and preparation methods in detail, and the process of practical preparation, especially according to the structural properties of H-bracket structure chooses 3D print as a preparation method for the practical preparation.The paper tests five kinds of FBG strain sensor in a way that simulates strains in engineering using strength-equal cantilevers, The tests proved these FBG strain sensors have sensing ability and that the H-bracket structure can prevent the chirp; finally obtains the sensitivity coefficient of FBG strain sensors. The performances of five FBG strain sensors are also evaluated.