An innovative corrosion-free precast prestressed concrete truss girder has been developed forshort- and medium-span slab-on-girder bridges. The girder consists of top and bottom concreteflanges connected by precast vertical and diagonal members made of fiber reinforced polymer(FRP) tubes filled with concrete. The verticals and diagonals are connected, respectively, to theconcrete flanges by means of glass FRP dowels and stud reinforcement made of corrosion-resistantsteel or FRP material. The flanges are pretentioned with carbon FRP tendons. The deck slab isreinforced with corrosion-resistant steel bars in the bottom transverse layer and with glass FRPbars in the bottom longitudinal and the top layers. The girders may be post-tensioned with externalcarbon FRP tendons to balance the slab weight and to provide continuity in multi-span bridges.The new system has the advantages of light weight and enhanced durability. The light weightreduces the initial cost and allows for longer spans. The improved durability reduces themaintenance cost and extends the structure's life span. This paper describes the general details ofthe system and presents an experimental evaluation of its critical components, namely, the FRPtubes and the truss connections. Two types of FRP tube and four types of connection areinvestigated. Results of testing eight connection specimens under static loading and four specimensunder fatigue are presented. The tests have shown excellent performance of the connection whenfilament wound tubes and continuous double-headed studs are used.
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