Health Monitoring of Steel Structures using Fiber Bragg Grating Sensors

A fiber Bragg grating (FBG) sensor is considered to be the most promising sensor for health monitoring system installed in building and civil engineering structures among advanced sensors. We have conducted tensile tests on FBG sensors to evaluate their mechanical and optical properties. It is shown that the FBG sensor expresses excellent linearity up to the large strain level which is enough for covering a yielding strain of steel material. Coefficients of thermal extension and contraction are obtained in the thermal extension test. Some steel plates to which FBG sensors were glued were loaded to investigate applicability of the sensors to real steel buildings. Under certain conditions, the FBG sensors could deliver precise strain outputs which are well correlated to those obtained from resistive foil strain gauges.