Behavior Of Full Scale Rc T Beams Strengthened In Shear With Externally Bonded Frp Sheets

"Shear deficiencies in many bridges may be considered even more critical than flexural deficiencies since shear failures occur without advance warning and are more catastrophic. Deficiencies in shear can be due to insufficient shear reinforcement, use of outdated design codes, a reduction in the steel area due to corrosion, or an increase in the service load due to change of occupancy for the structure. In recent years, many research studies have investigated the shear behavior of reinforced concrete (RC) beams strengthened with fiber-reinforced polymer (FRP) composites, however, most of them were conducted on small-scale specimens. Thus, analytical models and design equations developed from those studies may not predict the actual behavior of full-scale RC beams strengthened with FRPs. A comprehensive review and analysis of previous experimental studies and analytical models available in the literature, conducted as part of an ongoing NCHRP project, was updated in this study in order to identify the main parameters affecting the shear behavior of beams strengthened with FRP. An experimental study was then carried out using three full-scale RC T-beams in order to understand the behavior of full-scale bridge beams strengthened with FRP and to evaluate the effectiveness of anchorage systems for wet lay-up FRP applications. The main parameters investigated during the present study were the transverse steel reinforcement ratio and the effect of mechanical anchorage systems. Efficiency of existing analytical models and design equations in predicting the shear contribution of the FRP to the total shear resistance was also investigated based on the experimental results of this study. The experimental results indicated that an increase in shear strength is obtained when FRP is used. Further increase in the shear capacity can be reached by using a proper mechanical anchorage system. As confirmed from previous studies, an interaction between transverse steel reinforcement and FRP strengthening was also observed. Furthermore, the strain distribution on the FRP over the test region was found to be nonlinear, however for design purposes an average strain can be assumed to calculate the shear carried by the FRP sheets"--Abstract, leaf iii.