Evaluation of Protective Jackets Used on Reinforced Concrete Piles: Case Study of Hampton Roads Bridge and Tunnel

摘要

Corrosion of reinforced concrete piles located in a marine environment is of great concern, as it can reduce the load capacity of the piles and shorten their effective life. The Hampton Roads bridge and tunnel, located where the James River discharges into the Chesapeake Bay, was constructed with precast prestressed concrete piles, which have been exposed to a marine environment for 53 years. In the early 1980s, the Virginia Department of Transportation installed protective jackets on the piles to address the effects of chloride contamination and corrosion damage of the piles. The jackets were constructed by placing reinforcing mesh and a fiberglass stay-in-place form around an existing pile, and grouting the annular space with a mortar fill. The objective of these jackets was to prevent or mitigate corrosion activity by blocking water, oxygen, and chlorides from reaching the pile reinforcement. A study was undertaken to evaluate the effectiveness of the protective jackets through the use of visual evaluation, chloride analysis, and jacket autopsy. The study determined that corrosion was active in the precast piles and that the jackets were not mitigating corrosion activity in the piles. It was concluded that this type of jacket provided neither an effective repair to piles suffering from corrosion nor an effective method of protecting a pile from exposure to chloride-bearing water.