Enhancing axial behavior of RC columns: experimental study on GFRP confinement

This research goal is to measure the effect of both fully and partially wrapping glass fiber-reinforced polymer (GFRP) laminates strengthening on the axial performance of reinforced concrete (RC) by considering the corner or side position of the columns in the building plan for two rectangular and square section columns. Twelve RC columns were constructed and measured under axial loading. Samples were strengthened with GFRP laminates applied either as continuous or separate strips, fully and partially wrapped on three sides. To perform GFRP laminates over the columns' surfaces, MH-301 type epoxy resin has been employed with the density of 1.2 g/cm3. Then, the compressive strength, maximum deformation, stiffness, ductility, stress, and strain were evaluated. Empirical equations were also developed to forecast the stress-strain relationship and the resistance of the RC columns with different confinement conditions. Findings revealed that the confinement must be established on the short side of the rectangular RC columns to improve their maximum load-bearing capacity and deformation. Therefore, in rectangular specimens, the axial resistance of RC column was increased by 15% and 12% when specimens were confined fully and partially on the short side, respectively. Finally, it is stated that the suggested model could be utilized to precisely forecast the axial performance of RC columns strengthened with GFRP laminates with square and rectangular cross sections.