Experimental study on the effect of active confinement of AFRP fibers on the seismic performance of reinforcement concrete columns under axial and lateral loads

Fiber Reinforced Polymers (FRP) are often used for structural repairs to improve the strength and ductility of the structures. Previous studies have shown that utilizing active confinement in concrete structures can improve the seismic behavior of concrete columns under pressure. In this study, the behavior of concrete columns actively confined by AFRP fibers was investigated under the combined effects of axial compressive and cyclic lateral loads. Two concrete columns were actively confined by AFRP strips. In addition, a non-confined column (SCR) was utilized as a control specimen. Then all specimens were tested under axial and lateral cyclic loading. Experimental results showed that the ultimate compressive strength and axial strain of specimens with active confinement are improved compared to the SCR specimen. Also, due to the increased number of small cracks in the specimen, a higher extent of energy was absorbed under the applied loading. The loading protocol caused no rupture in the AFRP strips, and no shear crack and brittle failure in the specimens were observed.