EXPERIMENTAL EVALUATION OF LOAD DISTRIBUTION IN STEEL-FREE BRIDGE DECKS

摘要

Steel-free deck slabs, also known as fiber reinforced concrete (FRC) decks, utilize theconcept of internal arching action in transversely confined bridge deck slabs. The deck slabs that aredevoid of any reinforcement eliminate the potential of deck deterioration due to corrosion of internal steelreinforcement. The durability of the system has been established by rigorous laboratory testing understatic and dynamic load conditions. Several bridge decks have been constructed using this technology.However, very little study has been conducted on the load distribution characteristics of this innovativesystem.A 1/3-scale 6-girder bridge model has been constructed in the Heavy Structures Laboratory at DalhousieUniversity. The model represents a real-life, 24.7 m span steel-free deck bridge with six steel girdersspaced at 2.0 m and supporting a 225-mm thick FRC deck slab. The experimental work includes loadtesting of the model at three stages; 1) with only steel girders, diaphragms and edge beams, 2) withuncracked deck slab, and 3) with cracked deck slab.This paper will describe the test set-up and early experimental results. Prior to cracking of the deck slab,the load distribution is similar to that of a steel-reinforced concrete slab-on-girder bridge. After cracking ofthe deck, however, the absence of internal reinforcement leads to a change in the magnitude of transverseload distribution. The contribution of diaphragms and sensitivity of load distribution to deck cracking isidentified. The results will be of importance to both design guides, and field monitoring activities.