Experimental and Finite Element (ANSYS)-Based Evaluation of the Axial Compressive Behavior of CFRP-Confined Reinforced Concrete Members

Abstract

Reinforced Concrete (RC) members strengthened with externally bonded Carbon Fiber Reinforced Polymer (CFRP) fabric offer a lightweight, corrosion-resistant alternative to conventional jacketing. This study presents a combined experimental and nonlinear finite-element investigation of the axial compressive behavior of CFRP-confined RC cylindrical members. Six specimens (150 mm diameter × 300 mm height), cast in M20-grade concrete with Fe500 reinforcement, were divided equally into unwrapped control and CFRP-wrapped groups and tested to failure under a Compression Testing Machine (CTM). CFRP confinement increased the average ultimate load from 558.47 to 632.3 kN (13.2% enhancement) and raised compressive strength from 31.62 to 35.80 MPa, while axial deformation capacity improved by 44.4%, reflecting a marked gain in ductility and energy absorption. Control specimens failed abruptly through vertical splitting and spalling, whereas CFRP-wrapped specimens exhibited delayed cracking and a gradual, ductile failure governed by fabric rupture or debonding. A companion nonlinear finite element model, built in ANSYS Workbench using SOLID186 elements with a bonded CFRP concrete interface, reproduced the experimental trend: the predicted ultimate load rose from 527.53 to 568.78 kN (7.82% increase), and the maximum principal stress increased from 3.77 to 5.75 MPa. Comparison of experimental and numerical ultimate loads showed deviations of 5.5% and 10.0% for the unwrapped and wrapped configurations, respectively, confirming that the calibrated model captures the governing confinement mechanics while slightly overestimating stiffness owing to the idealized bond assumption. The results substantiate CFRP wrapping as an effective, code-complementary retrofitting strategy for axially loaded RC members and demonstrate that validated ANSYS simulation can reliably support design-stage prediction of confined member response.