Repair of Morganza Spillway Bridge Bent Pile Cap Using Carbon Fiber Reinforcement (CFR).

摘要

The pile cap of an end bent of the Morganza Spillway Bridge suffered extensive damage at the girder bearing locations, particularly on the side where the pounding of the girders by the adjacent concrete deck located on the approach side of the bent. The primary repair of the damaged pile cap and the replacement of the bearing plates were completed by the contractor working on the project. Structural grade high-adhesive material epoxy concrete was utilized to patch the damaged areas of the pile cap. In similar repairs conducted earlier, the repair under the bearing plates delaminated. Therefore, the repaired areas of the pile cap, namely the bearing plate locations, were strengthened by preventing delamination of the repair material by confining it with high modulus carbon composite wrapping. An inorganic polymer coating that provides UV protection and prevention of deterioration was applied to the entire pile cap surface. This coating also has self-cleaning properties that will prevent and eliminate the growth of any mold or mildew and deposits of organic materials. The project was conducted to demonstrate the application of high strength composites for rehabilitation of transportation infrastructure. Overall, the project was a complete success. The systems cured within 24 hours and rain on the second day of the repair process had no ill effects on the system. There was no distress of any kind in either the repair zone or the coating during the entire two-year monitoring period. Because the system is inorganic, it is expected to function properly for 10 to 30 years. This composite has shown long-term durability as the first application was 20 years ago and is still performing well with no distress. Even debris that came through the construction expansion joint did not scratch or damage the coated surface. This project also provided an opportunity to demonstrate the self-cleaning properties of the coating. The uncoated surface (behind the scaffolding during the repair) was covered with mold and mildew growth, whereas the coated surface was completely clean. Preparation of the resin and placement of the carbon reinforcement was easily carried out by students and therefore trained personnel, such as DOTD maintenance crews, can easily use this coating and resin systems for future