Fundamental Study on Stress Evaluation of Pile Using Optical Fiber Sensors

Recently, sensors that use an optical fiber have spread in the field of civil engineering. The BOTDR (Brillouin Optical Time Domain Reflectometry) method using an optical fiber sensor has characteristics of continuous measurement for a long distance. The purpose of this study is to examine the method of stress distribution through piles by means of optical fiber sensor. In this study, the model vertical load tests at the gravitational acceleration field were carried out to obtain the fundamental characteristics of FBG (Fiber Bragg Grating) for estimating the stress distribution of pile. The results of model vertical load tests have a good correlation between the measured strain values by strain gauges and that by the optical fiber sensors. The result implies that it is possible to measure the strain of pile by using the optical fiber sensors. Therefore, it is said that the stress of pile is also evaluated accurately because the accurate strain can be measured.