Repair of corroded steel bridge girder end regions using steel, concrete, UHPC and GFRP repair systems

Abstract

Practical means of affecting in situ repair of corrosion-induced section loss of steel bridge girders at their supports are compared. Potential repair strategies are reviewed leading to large-scale experimental evaluation of four methods of repair: conventional bolted steel repair, encasement in conventional reinforced concrete (RC), encasement in ultra-high performance concrete (UHPC), and reinforcement with externally bonded fiber-reinforced polymer (FRP) plates and sections. Modified W24x55 girders representing half-scale 1400 mm deep plate girders were used. Section loss mimicking typically-observed severe corrosion was machined into the girder ends. Monotonic load tests to failure were conducted on the repaired girders and companion tests were conducted of identical specimens subject first to one million cycles of fatigue loading before being loaded to failure. Results indicate the efficacy of conventional bolted steel repair methods. UHPC and RC encasement was also shown to perform well and may be suited to certain scenarios. Despite extensive surface preparation and chemical enhancement, the bond of the FRP system to the damaged substrate steel was poor; this system is not an appropriate repair method for this damage scenario.