RETROFIT STEEL CORRODING RC BEAMS USING CFRP COMPOSITES: NLFE ANALYSIS

Corrosion of steel reinforcement is one of the main durability problems facing reinforced concrete infrastructures worldwide. Steel degradation and/or cracking of concrete both cause severe reduction in bearing capacity, leading ultimately to failure. The potential of repairing corroded concrete beams with two configurations of carbon-fiber reinforced polymeric (CFRP) composites was investigated with a nonlinear finite Element (NLFE) model. CFRP composites were assumed to be either bonded directly to existing concrete or to a new concrete cover; replacing the old one. The data generated showed that the load-bearing capacity and stiffness for concrete beams, as long as corrosion levels were below 10%, can be fully restored. However, the ductility in terms of deflection at failure would be reduced, especially for repair techniques that involved anchoring with CFRP sheets. For corrosion levels greater than 10%, attaching CFRP composites to a new concrete cover contributed to additional improvements in load capacity and stiffness ranging from 10 to 15% of that achieved from similar repairing on existing concrete. The failure modes indicated that debonding failure prevailed, and that the extent of debonding prior to failure depended upon the corrosion level and on whether the concrete cover was replaced or not.