Structural Behavior of Lightweight Concrete Bridge Deck Slabs Reinforced with Basalt FRP Bars
thesisposted on 28.10.2014, 00:00 by Fadi Alsharif
The implementation of Basalt Fiber Reinforced Polymers (BFRP) in bridge decks supported on girders, where deflection is not an issue, has the potential to offer an efficient solution that is corrosion resistant, durable and cost effective. In this paper, the structural behavior of Lightweight Concrete (LWC) bridge decks, reinforced with BFRP reinforcing bars, was studied. The research program included experimental testing of eight LWC bridge deck specimens reinforced with BFRP reinforcing bars. The cross section of the specimens was 18 x 8 in. with a length to height ratio (L/H) equal to 9, 10, 12 and 13. The purpose of testing program was to study the structural behavior of bridge decks supported on girders, in addition to the pre-cracking and post-cracking behavior till the failure of the specimens. Two of the specimens were simply supported with a span length of 6.67 ft. and (L/H) equal to 10; and were reinforced with 5 BFRP bars of diameter 0.625 in. and 5 bars of diameter 0.5 in. at the bottom, respectively. The ratio of the bottom to the balanced reinforcement areas (ρ_f⁄(ρ_fb)) were 4.1 and 2.6, respectively. Two additional specimens were continuously supported with two spans of 8.67 ft. each, (L/H) ratio of 13, and were tested for positive and negative moment capacities. They were reinforced with 5 BFRP bars of diameter 0.625 in. and 5 BFRP bars of diameter 0.5 in. at the bottom with (ρ_f⁄(ρ_fb) )equal to 4.1 and 2.6, respectively. The specimens were reinforced at the top with 6 bars of 0.625 in. diameter and 6 bars of 0.5 in. diameter with (ρ_f⁄(ρ_fb) )equal to 5.1 and 3.2, respectively. The other specimens were simply supported reinforced as the two continuous decks, with a varying span of 6 and 8 ft., and (L/H) equal to 9 and 12 respectively. The nominal moment capacities (Mn) were accurately predicted by the specifications of the ACI 440.1R (2006), however the ultimate moment capacities (Mn) were conservative due to a lower strength reduction factor (ϕ). The deflections of the reinforced slabs were high due to the relatively lower modulus of elasticity of BFRP bars.