Corrosion aging of reinforced concrete T-girders strengthened with near-surface-mounted composites

This paper discusses the effect of corrosion aging on the flexural response of reinforced concrete (RC) T-girders strengthened with near-surface-mounted (NSM) composite reinforcement. The study comprised analytical modeling and experimental testing of 15 RC T-girders. Twelve girders were strengthened in flexure with either two or four NSM carbon-fiber-reinforced polymer composite strips, and three girders were not strengthened to act as benchmarks. In some girders, the NSM composite reinforcement was supplemented by intermittent U-shaped composite wraps along the beam span. Five girders were not corroded and 10 were subjected to accelerated corrosion aging for 30 and 100 days that corresponded to average measured tensile steel mass losses of 5 and 15%, respectively. Corrosion damage and cracking reduced the load capacity of the girders strengthened by NSM composites without U-wraps. The inclusion of U-wraps in the strengthening regime prevented premature peeling failure of the concrete cover. No reduction in the load capacity was recorded for the corroded girders strengthened with NSM composites combined with U-wraps. The residual load capacities of all strengthenedcorroded girders were substantially higher than that of the control girder. An analytical model was introduced that can predict the load capacity and failure mode of corroded T-girders strengthened with NSM composites. A comparison between the analytical and experimental results demonstrated the accuracy and validity of the model.