Experimental Study of Cyclic Behavior of Concrete Bridge Columns Reinforced by Steel Basalt-Fiber Composite Bars and Hybrid Stirrups

This paper presents an experimental study of concrete columns reinforced by steel basalt-fiber composite bars (SBFCBs) and steel basalt-fiber hybrid stirrups (SBFHSs) as innovative hybrid reinforcements. Four RC columns were cast; one column, which was reinforced longitudinally and transversely with traditional steel bars, served as a reference. Three columns were constructed with varying amounts of a basalt fiber-reinforced polymer (BFRP) material in the SBFCBs; the postyield stiffness ratio of the hybrid reinforcement was 0.1, 0.3, or 0.5. All the columns were subjected to a constant axial load and lateral cyclic loading. Several parameters affecting the columns' responses, such as the BFRP reinforcement ratio and the ratio between the postyield and elastic stiffness of the longitudinal bars, were examined. The experimental results showed that the failures of all four columns were flexural, and the postyield stiffness of the longitudinal reinforcement had a significant effect on the stiffness, bearing capacity, residual deformation, and amount of energy dissipated by the test columns.