A HYBRID FRP-REINFORCED SLAB-ON-TRUSS GIRDER SYSTEM FOR SHORT AND MEDIUM SPAN BRIDGES

摘要

An experimental evaluation of a hybrid FRP-concrete slab-on-truss girder bridge system is presented. The girders consist of pretensioned top and bottom concrete chords connected by vertical and diagonal truss members made of concrete-filled fiber-reinforced polymer (FRP) tubes. The truss members are connected to the chords by means of long double-headed glass FRP (GFRP) bars. The chords are also reinforced with GFRP longitudinal bars and transverse stirrups. The deck slab is connected to the top chords of the girders using double-headed GFRP studs. The truss girders are thus lighter and more durable than the conventional precast I-girders. The experimental program consisted of fabricating and testing eight full-scale truss girders including four 2.83-m (9.28-ft) long 2-panel trusses and four 9.82-m (32.22-ft) long 8-panel trusses, all having the same cross-section dimensions with 1.32-m (4.33-ft) overall depth. Two of the 2-panel and two of the 8-panel girders were reinforced with GFRP reinforcement. The remaining four were reinforced with steel and used as control specimens. Two of the 2-panel and two of the 8-panel girders were covered with a one-meter wide concrete slab connected to the girder top chord by either steel or GFRP double-headed studs. Tests under static loading showed excellent performance of the system in terms of strength and stiffness.