Study on the Structural Deformation Monitoring Based on Distributed FBG Sensing Techniques

The deformation is an important parameter in structural health monitoring, and a conjugate beam method based on long-gauge fiber Bragg grating distributed strain sensing techniques is proposed to obtain the deformation of a structure. Some experiments are carried out to study the accuracy of this method using a four point bending RC beam under a step loading manner. The deformation obtained with the proposed method agrees well with those obtained with the conventional dial gauge in low loading steps. In addition, some measure is put forward to calibrate the proposed method and improve its accuracy at high loading steps, especially after the initiation of concrete cracks.