AXIALLY-COMPRESSED BEHAVIOR OF DEFICIENT SHORT STEEL COLUMNS STRENGTHENED WITH CARBON-FRP

Abstract

Structural components surpassing their service life demand extensive repairs, constituting a significant share of the annual budget in advanced nations. This financial commitment arises from the vulnerability of these elements to diverse damages, and the considerable expense associated with reconstruction. Among these components, compression members, notably columns, are pivotal in supporting and transferring both vertical and lateral loads in a structure. Columns inevitably buckle under loads nearing their full capacity, leading to failure. Consequently, researchers are actively exploring retrofitting techniques to enhance column resistance through novel materials and methods. Compression members, often succumb to damage due ‎to factors like aging, deterioration, and corrosion, leading to diminished durability. This study ‎delves into the impact of dimensions and damage location on steel square members under axial ‎loads. Primary damages are intentionally introduced both vertically and horizontally at the ‎middle and corner positions, and retrofitting is performed using Carbon Fiber Reinforced Polymers (CFRP). Experimental ‎testing and ABAQUS software modeling were conducted on eleven steel samples, revealing that ‎compression members undergo local buckling and lateral rupture in damaged zones under axial ‎loads. Notably, Corner damage located at mid-height of the column results in the most substantial loss of strength, reducing ultimate load by 17% compared to undamaged controls. Reinforcement using four layers of carbon fiber enhances load-bearing capacity by up to 18%. Full column wrapping increases stiffness and delays local buckling, improving resistance to axial failure.