Experimental study of non-circular concrete elements actively confined with shape memory alloy wires

• SMA straight wires are effective in applying bidirectional confinement to square elements.
• Moderate active confinement pressure of 1.7 MPa increased the concrete ultimate strain to 7.4%.
• Active confinement using SMAs reduced concrete dilation by almost half compared to FRP wraps.
• Under cyclic loading, SMA was able to limit stiffness degradation significantly compared to FRP.

This study focuses on developing a novel scheme for applying external active confinement to non-circular concrete elements that lack ductility using shape memory alloys (SMAs). A total of 13 concrete elements (prisms) are tested under monotonic and cyclic uniaxial compression load. The compressive stress–strain relationships of the SMA confined concrete elements are examined and compared with the behaviors of elements confined with conventional glass fiber reinforced polymer (GFRP) jackets. The results clearly show a significant improvement in the ultimate strain and residual (post-peak) strength of concrete elements actively confined with SMA compared to that of GFRP confined elements.