Preservation of Missouri Transportation Infrastructures: Life Expectancy Modeling for FRP Strengthened Concrete Bridges; Final rept

摘要

The use of fiber reinforced polymers (FRP) in repairing and strengthening bridges has been an active area of research and implementation in recent years. In particular, adhering FRP to the tension face of reinforced concrete (RC) beams has provided an increase in load carrying capacity and extended the service life of structures. However, the life expectancy of this technology has not yet been fully investigated or documented due to insufficient data. In this report, the authors present one possible strength degradation approach using analytical modeling to determine the life expectancy of FRP strengthened bridges. An actual Carbon FRP field strengthened bridge in Dallas County, Missouri, USA, was utilized to demonstrate the life expectancy approach. The Dallas County Bridge P-0962 was constructed in 1955 and strengthened in 2003. To predict the life expectancy behavior of the bridge structure, a theoretical model was derived using basic concepts, past research, and the properties of specimens tested for critical chloride concentration. An interaction model for life expectancy estimation is based on the reduction of moment capacity due to corrosion of reinforcement before and after strengthening, bond degradation of FRP and substrate concrete, and degradation of FRP material itself based on fatigue analysis. This model is the first possible approach to determine the life expectancy of FRP strengthened structures based on the statistical data available in literature.