Strengthening a concrete slab bridge using CFRP composites

This paper describes the feasibility and efficiency of using CFRP composites as a strengthening system to upgrade the load carrying capacity of a three-span continuous (17.17 ft/17.33 ft/17.25 ft) [5.23 m/5.28 m/5.26 m] concrete slab bridge constructed (ca. 1946) in the City of Phoenix spanning the canal system and carrying an average daily traffic of 30,000 vehicles. Given the relatively short canal dry-up period (three weeks), a fast-paced approach to strengthen and improve the load carrying capacity of the existing structure was required. Externally applied CFRP wraps were used for the soffit in the positive moment regions; and carbon fiber rebars embedded in the concrete were used over the pier locations in the negative moment regions. Based on load test results, the externally applied CFRP composite materials significantly enhanced the structural performance of the 19th avenue bridge and improved its load rating at a fraction of the cost of total replacement and at a fraction of the time.