Title: Texas’ Use of CFRP to Repair Concrete Bridges
Author(s): D. Yang, B.D. Merrill, and T.E. Bradberry
Publication: Special Publication
Appears on pages(s): 39-57
Keywords: TxDOT, Bridge, FRP, CFRP, continuous fiber, carbon fiber, epoxy resin, polymer matrix, compatibility, tensile reinforcement, wet layup, flexibility, structural repair, sacrificial reinforcement, strengthening, confinement, impact damaged, fire damaged.
The Texas Department of Transportation (TxDOT) maintains over 33,000 on-system bridges. A considerable number of these bridges are damaged each year by extreme events or structural deterioration and must be repaired rapidly. Externally bonded carbon fiber reinforced polymer (CFRP) composites provide TxDOT with a viable technique for repairing many damaged concrete bridges. CFRP has been used extensively as structural reinforcement for its exceptional engineering properties, simplicity, flexibility, and rapid placement. TxDOT began using CFRP in 1999 and has repaired more than 30 impact-damaged concrete bridges, resulting in considerable time and money savings. This paper summarizes TxDOT’s experience repairing concrete bridges damaged by impact, fire, corrosion, and alkali-silica reaction (ASR), focusing on damage assessment, determination of reparability, and procedures essential for effectiveness. TxDOT engineers have made a conscious effort to utilize CFRP materials to repair impact-damaged beams. CFRP has been used to supplement prestressed strands to restore flexural capacity, laterally ‘harden’ bottom flanges against damage from re-impacts, and enhance the ductility, shear strength, and integrity of concrete bridge beams. For repeatedly impact damaged beams, CFRP has been used as ‘sacrificial’ reinforcement to protect the primary reinforcement, the prestressed strands, and to increase survivability, thus preserving the structure. Recommendations regarding the effectiveness of such CFRP repairs are presented.