| Three different Carbon Fiber Reinforced Polymer (CFRP) repair techniques are examined to determine how effectively each method can restore the ultimate flexural capacity of impact-damaged prestressed concrete girders. The number of severed prestressing strands and the amount of CFRP repair material applied are varied to create a large repair matrix. The ultimate moment capacity was calculated using the program XTRACT. Capacities were also evaluated using AASHTO and ACI specifications.;The prototype girder's geometry is based on an impact-damaged I-girder from a bridge in Eastland County, Texas, which was repaired using CFRP in 2006 using conventional externally bonded CFRP. The CFRP repair methods examined in this study were near surface mounted (NSM) CFRP, externally bonded (EB) CFRP, and bonded post tensioned (bPT) CFRP. The area of the girder available for repair was limited to the bottom soffit for near surface mounted CFRP and bonded post tensioned CFRP; however, the externally bonded CFRP was applied on the bulb as well as the soffit. The range of the repairs examined were approximately 25%, 50%, and 75%, and 100% of the maximum practical amount of CFRP which could be applied based on the girder geometry, ACI guidelines, and manufacturers' recommendations.;The geometry of the girder limited the amount of CFRP which could be applied, so the repairs could only completely restore the ultimate girder capacity when very few strands were damaged and the maximum amount of CFRP was used. However, the CFRP techniques were shown effective at restoring some of the lost capacity and thus are an option if only a portion of the lost capacity must be restored. The study also showed that, in some cases, repairs are completely ineffective and the girder capacity is not increased beyond the damaged state. Using the results of this study, engineers can determine when repairing a girder will be effective and the extent to which the repair restores lost capacity. |
