Analytical Load-Moment Interactions of Shape Modified Square Hollow RC Columns Subjected to Bi-Axial Eccentric Loading: A Parametric Study
Received: 17 February 2025 | Revised: 17 March 2025 | Accepted: 28 March 2025 | Online: 4 June 2025
Corresponding author: Mohammed Tareq Jameel
Abstract
This paper presents analytical load-moment interactions for shape modified square hollow Reinforced Concrete (RC) columns into circular and wrapped with Fiber Reinforced Polymer (FRP) under biaxial eccentric loadings. The analysis is performed using strip integration methods along with theoretical stress and strain constitutive models of concrete, adopted from the existing studies. The theoretical predictions show good agreement with the experimental results available in the literature for both biaxially loaded FRP-wrapped square solid RC columns and uniaxially loaded FRP-wrapped, shape-modified square hollow RC columns, in terms of axial load capacity and corresponding bending moment. The effect of the number of FRP wrapping layers, compressive strength, and hole size were investigated for the biaxially loaded shape modified square hollow RC columns. Four regions are determined to form the interaction diagram, including: pure compression, balance point, pure tension and any other point. The results reveal that higher axial loads and bending moments can be achieved with an increased number of FRP layers and greater concrete strength. Conversely, a larger hole size reduces confinement efficiency, and overall FRP confinement effectiveness is diminished as biaxial eccentricity increases.
Keywords:
hollow columns, confinement, shape modification, biaxial eccentricity, concrete segmentDownloads
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