MODELING REINFORCED CONCRETE GIRDERS STRENGTHENED WITH PRESTRESSED NSM-CFRP STRIPS AND RODS

Many concrete bridges are in need of upgrading in order to increase their structural capacities. The use of fiber composites in retrofitting concrete girders has always been used because of their superior performance as compared with other strengthening techniques. Near-Surface-Mounted (NSM) Carbon Fiber Reinforced Polymer (CFRP) technique is one of the newest strengthening/retrofitting technique used for rehabilitating and upgrading the structural performance of reinforced concrete girders. The strengthening procedure involves embedding CFRP reinforcement (rods or strips) inside a pre-cut groove filled with epoxy. The size, number, and location of groove depend on the required level of strengthening. In order to enhance the serviceability performance of concrete girders, prestressing the CFRP reinforcement would increase further the cracking load and reduce the deflection at service load. This paper presents the first phase of the research program, involving modeling eight reinforced concrete beams strengthened with prestressed NSM CFRP rods and strips and tested in flexure, published elsewhere in literature. A 2D FE model has been developed using ABAQUS for this purpose. A comparison is presented between the analytical and experimental results considering; load-deflection curves and strain profile of the CFRP reinforcement. The comparison indicates that the proposed model can predicted precisely the behaviour of concrete beams strengthened with prestressed NSM CFRP reinforcement.