Structural health monitoring of offshore structures using Fiber Bragg gratings
Over the last few years, optical fiber sensors have seen an increased acceptance as well as a widespread use for structural sensing and monitoring in civil engineering. FBG sensors have all the advantages attributed to the optical fibers. In addition, they can be easily multiplexed in a serial fashion along a single fiber. The experimental program includes testing of three two-way reinforced concrete slabs. One normal strength concrete slab (NS) and two high strength concrete slabs (HS) will be selected for the experimental investigation. Two sets of FBG and ESG strain sensors will be mounted on tensile rebars. Another FBG sensor will be embedded inside concrete slabs. All tests will be carried out using a closed-loop (MTS) testing machine. The load will be applied by means of a hydraulic actuator. During testing, the slabs will be carefully inspected and cracks will be marked at each load increment. Deflection at the slab centers will be measured with an LVDT gages. The loading process involves a cycle test (serviceability limit state test) and a failure test. In both these two tests, the strain changes will be monitored using the FBG sensors and the electrical strain gauges embedded in the slab.