Unveiling the cyclic behavior of FRP-SHCC confined concrete: An integrated experimental, modeling, and simulation approach

Abstract

The utilization of fiber reinforced polymer (FRP) textile/grid reinforced strain-hardening cementitious composites (SHCC, FRP-SHCC) for the purpose of seismic strengthening concrete elements has emerged as a novel technique in civil engineering. The cyclic behavior of both cylinders and prisms confined with carbon/basalt FRP reinforced normal/high strength SHCC were investigated through an integrated approach combining experimental test, stress-strain modeling, and lattice discrete particle model (LDPM) simulation. Both experimental and simulation results have consistently demonstrated that the cracking strength of FRP-SHCC is the critical factor influencing confinement effectiveness. The proposed ultimate strength and envelope stress-strain model, which accounts for the nonlinear tensile behavior of CFRP-SHCC composites, provides an accurate prediction of the mechanical response of CFRP-SHCC composite-confined concrete. The simulation method based on LDPM possesses the capability to accurately capturing its cycling stress-strain behavior, ultimate strength/strain and dissipated energy. Furthermore, the simulation results suggest that the initial constraint stiffness of BFRP-SHCC on the core column is insufficient compared to CFRP-SHCC, leading to varying degrees of strength degradation in concrete after reaching its peak strength without confinement. However, due to its relatively high ultimate strain, as constraint stiffness improves the strength of confined column transitions from softening into a hardening phase, and exhibiting superior ductility compared to the CFRP-SHCC confined column.