Assawoman Bay Bridge

The Assawoman Bay Bridge, Maryland, consists of 139 spans. Longitudinal, transverse and shear cracks were observed during past routine inspections of the prestressed concrete box beams and AASHTO girders. The first phase of the project consisted of conducting an extensive investigation to determine the cause of these cracks and their affect on the performance and durability of the bridge. The investigation consisted of performing a hands-on inspection of the bridge elements, invasive testing of selected locations, collection of core samples, and performing chloride ion content analysis along the bridge.

The results from chloride ion penetration analysis and testing indicated severe corrosion and deterioration in the main span and five box section spans. The AASHTO girder drop span was deteriorated to the extent that complete replacement of the span was necessary. Analysis of the existing damage showed significant deterioration, due to corrosion of both the box beams and the AASHTO girders, that required immediate structural repairs. The results of the investigation were presented in a report recommending replacement of the drop span and preventative maintenance such as sealing and painting concrete surfaces, epoxy injection of cracks and structural strengthening of selected AASHTO girders and box beams using carbon fiber reinforced polymers (CFRP). The construction work for the entire project was completed successfully within six months at a construction cost of approximately $1,800,000, considerably less than the $12M estimate prepared by another consultant.