FBG Study On Some Key Issues For Reinforced Concrete Structure Health Monitoring

For the sake of long-term health monitoring of reinforced concrete structure, the surface-bonded and embedded fiber Bragg grating (FBG) strain sensors have been designed and developed based on the study on FBG's sensing properties. The strain and temperature sensing properties of the designed sensors and temperature compensation technique have also been studied. Furthermore, the surface-bonded and embedded FBG strain sensors have been applied to the strain measurement for the structure of steel, concrete and reinforced concrete. The research work will be illustrated from the following three aspects:Firstly, the strain and temperature sensing properties have been studied based on the Bragg equation and the affection of central wavelength on the FBG's sensing sensitivities have also been analyzed. Then, the cross-sensitivity of strain and temperature are studied and the reference FBG method is considered as a simple and reliable method comparing to other temperature compensation methods. Finally, the FBG's sensing properties have been studied by the experiments of equal-strength beam and temperature calibration. The research results show that the experimental results agree with that from theoretical analyses well, that FBG's axial strain sensitivity is much bigger than transverse strain sensitivity, and if the central wavelength doesn't change a lot the affection of central wavelength on sensitivity can be ignored.Secondly, considered the need of long-term monitoring for civil engineering, the structure, materials section and packaged techniques for...