Effects of wrap thickness and ply configuration on composite-confined concrete cylinders

The behavior of small-scale fiber reinforced polymer (FRP) wrapped concrete cylinders under uniaxial compressive loading was investigated through nonlinear finite element analysis. Two parameters were considered for this numerical study: the FRP wrap thickness, and the ply configuration. Performances of numerical models with “hoop-angle-hoop” and “angle-hoop-angle” ply configurations were compared, where the terms “hoop” and “angle” indicate that wraps were oriented at an angle of 0° and 45° in reference to circumferential direction, respectively. The finite element analysis results showed substantial increase in the axial compressive strength and ductility of the FRP confined concrete cylinders as compared to the unconfined ones. The cylinders with “hoop-angle-hoop” ply configuration in general exhibited higher axial stress and strain capacities as compared to the cylinders with the “angle-hoop-angle” ply configuration. The increase in wrap thickness also resulted in enhancement of axial strength and ductility of the concrete cylinders.