STATIC LOAD BEHAVIOUR OF HYBRID FRP-CONCRETE TWO-PANEL TRUSS GIRDERS REINFORCED WITH DOUBLE-HEADED GFRP BARS

摘要

The results of an experimental investigation into the behaviour of precast hybrid FRP-concrete, two-panel truss girders under static loading are presented. The investigation is part of a comprehensive research program on the development of a corrosion-free system for short and medium span bridges. The truss girders consist of pretensioned concrete chords connected by vertical and diagonal truss elements made of glass FRP tubes filled with concrete. The truss elements are reinforced and connected to the top and bottom chords by means of long double-headed steel or glass FRP bars. The top and bottom chords are also reinforced with glass FRP stirrups and double-headed longitudinal bars. This new system is expected to reduce the initial and maintenance costs and enhance the durability of bridges, and thus, extend their useful life. Moreover, by replacing the solid concrete web of traditional precast I-girders with the truss elements, the weight of the structure is significantly reduced, and thus, longer spans can be achieved and the number of supporting piers and size of the substructure can be reduced. The main objective of the research presented herein was to examine the efficiency of the FRP in comparison to steel reinforcement. The work included fabricating and testing three large-scale two-panel truss girders with an overall depth of 1.32 m and length of 2.83 m. The test parameters included the type and amount of reinforcement. The girders were tested under monotonic loading up to failure. The tests showed excellent results in terms of strength, stiffness, and connection performance of the truss girders.