Experimental Testing and Strut-and-Tie Modeling of Full-Scale Precast Concrete Girders with FRP Repaired End Regions

Bridges located in cold regions are susceptible to extreme deterioration due to harsh climate conditions. Distressing of girder’s end regions is among the most common damage types in these bridges. This work focuses on addressing this type of damage through the use of a fiber reinforced polymer (FRP) repair scheme. Three-point-bending tests are conducted on the control, damaged, mortar repair and carbon fiber reinforced polymer (CFRP) repair cases of bridge girders that are taken out of service. Test results are analyzed to investigate the effectiveness of FRP to repair precast concrete (PC) girders with damaged end regions. Furthermore, since the damage is mainly localized at girder’s end region where beam theory is invalid, the behavior of FRP repaired end region (D-region) is studied using the strut-and-tie method. Based on the test results, a strut-and-tie model (STM) is proposed to estimate the shear capacity of the girder with the FRP repaired end region. The outcome of the experimental work shows that the FRP laminate repair system is effective in recovering and improving the shear behavior of the girder including both peak force and ductility. The proposed STM can be used to predict the shear capacity of the PC girder with a similar damage pattern to the one considered in this study.