Flexural Behavior of Preloaded RC Slabs Strengthened with Prestressed CFRP Laminates

AbstractMany studies performed on reinforced concrete (RC) members strengthened in flexure with externally bonded (EB) fiber-reinforced polymers (FRPs) have indicated quite low strengthening efficiency caused by debonding of the FRP from the concrete surface prior to the capacity of the FRP material being achieved. It should be emphasized that although flexural strengthening with FPR increases the load-bearing capacity of RC members, it has little effect on the serviceability limit state (i.e., cracking moment and deflections). Prestressing the EB FRP has been proposed as a method of increasing utilization of the FRP tensile strength and of improving the efficiency of strengthening in terms of serviceability limit states. An experimental research program consisting of three series of RC slabs with variations in the longitudinal steel reinforcement ratio, concrete strength, preloading level before strengthening, and adhesion between the CFRP laminates and the concrete is described. A practical and unique a...