An Innovative Hybrid FRP-ConcreteBridge System

Abstract

Synopsis: An innovative corrosion-free system for shortand medium-span bridges consisting of precast prestressed concrete truss girders and cast-in-situ concrete deck has been developed. Advantages of the new system include reduced self-weight and enhanced durability. The girders consist of top and bottom concrete flanges connected by precast vertical and diagonal members made of fiber reinforced polymer (FRP) tubes filled with concrete. Glass FRP dowels and corrosion-resistant steel stud reinforcement are used, respectively, to connect the vertical and diagonal members to the concrete flanges. The flanges are pretentioned with carbon FRP tendons. The deck slab is reinforced with corrosion-resistant steel bars in the bottom transverse layer and with glass FRP bars in the bottom longitudinal and the top layers. The girders may be posttensioned with external carbon FRP tendons to balance the slab weight and to provide continuity in multi-span bridges. The general details of the system and an experimental evaluation of its critical components, namely, the FRP tubes and the truss connection, are presented. Three types of FRP tube and four types of connection are investigated. The results of testing eight connection specimens under static loading are presented. The tests have shown superior performance of the connection when filament wound tubes and continuous double-headed studs are used.