Serviceability and moment redistribution of continuous concrete members reinforced with hybrid steel-BFRP bars

Test results of 12 two-span concrete specimens internally-reinforced with basalt fiber-reinforced polymer (BFRP) or hybrid steel-BFRP bars are reported in this paper. Six specimens were designed to be over-reinforced whereas the remaining six specimens were under-reinforced. The specimens had different hogging-to-sagging reinforcement ratios. Specimens with hybrid steel-BFRP bars were designed in a way to have hogging-to-sagging nominal moment strengths similar to those of their counterpart specimens reinforced with BFRP bars only. Specimens reinforced with hybrid steel-BFRP bars exhibited less deflections and smaller crack widths at service load than those of their counterparts with BFRP bars only. The hybrid-reinforced specimens were, however, able to undergo significant deformations prior to failure comparable to those exhibited by their counterparts reinforced with BFRP bars only. The behaviour of the specimens reinforced with BFRP bars only deviated from the elastic response. This deviation tended to increase by decreasing the hogging-to-sagging reinforcement ratio. Specimens reinforced with hybrid steel-BFRP bars exhibited less deviation from the elastic response compared with that of their counterparts reinforced with BFRP bars only.