Research Description
Reinforced concrete (RC) columns are critical structural elements in buildings where their failure may precipitate collapse. Seven large-scale 22 MPa compressive strength RC columns (200×200×1500 mm) were tested under eccentric loading (e/t=0.25). The strengthening materials (BFRP, CFRP), wrapping methods (full, partial), number of layers, and orientation were varied. Hybrid BFRP-CFRP wrapping provided the greatest enhancement, increasing the ultimate load by 44%, lateral displacement capacity by 152%, and energy absorption by 379% compared to unconfined columns. Finite element models in ANSYS 19.0 accurately predicted behaviour with maximum differences of 9.8% for ultimate load, 10.8% for displacement, and 15.4% for energy absorption. Parametric finite element analysis was conducted to further assess the influence of eccentricity magnitude and cross-sectional aspect ratio on the performance of FRP-confined RC columns. Increasing the eccentricity ratio from 0.0 to 0.9 reduced the ultimate load by approximately 21% (three horizontal BFRP layers). Additionally, increasing the cross-sectional aspect ratio from 1.0 (square section) to 1.8 (rectangular section) further reduced the ultimate load by about 40%, indicating a noticeable decline in confinement efficiency with more elongated sections, especially under high eccentricity loading.
