Smart FRP-OFGB bars and their application in reinforced concrete beams

Fiber Reinforced Polymer (FRP) has become more and more popular as construction material in civil engineering due to its advantages of corrosion-resistance, high strength, nonmagnetic, fatigue-resistance and so on. Optical Fiber Bragg Grating (OFBG) is now widely accepted as smart sensor due to its advantages of electric-magnetic resistance, small size, distributing measurement, durability, and so on. Combined the strength properties of FRP with the sensing properties of OFBG, a new kind of smart FRP-OFBG composite bars have been developed, and their mechanical properties, microstructures and sensing properties are also studied. The experiment of FRP-OFBG reinforced concrete beams under static load has been done, and the strain of FRP bars and cracking of concrete are monitored, especially the slip between FRP bars and concrete, and the strain distribution of the beams. The experimental results show that FRP-OFBG is a wonderful construction material for civil engineering. As smart sensing element, FRP-OFBG bars have overcome the difficulties of embedment installation in concrete structures, and can be conveniently used in reinforced concrete structures as sensors as well as reinforcing bars.