Capacity of Eccentrically Loaded HSS Columns Strengthened with CFRP Laminates

Abstract

Carbon Fibers Reinforced Polymer (CFRP) is considered as an effective material in upgrading the strength and stiffness of steel structures due to its considerable light weight and its ease in bonding. Large number of researches has focused on strengthening beams and columns for steel and RC members. Limited researches have investigated the effect of CFRP on beam-columns subjected to both bending and normal forces. The steel members strengthened with CFRP plates are susceptible to various failure modes that can limit the utilization of the strengthening method. De-bonding or crushing of CFRP plates are considered the main reasons that control the capacity of the structural member. This study investigates the behaviour of steel HSS beam-columns strengthened with CFRP plates on both sides of the HSS section. Different slenderness ratios under various levels of load eccentricities are considered in the study. Finite element models are developed and verified against experimental results to investigate the behaviour of HSS beam-columns. FEM takes into account all possible failure modes that occur to the strengthened beam-column members. The study showed significant increase in beam-column capacity up to 60% depending on the member slenderness ratio and load eccentricity values. It was also found that application of this strengthening system is very effective for slender specimens with small eccentricity while opposite is true for short specimens. Finally, investigation results and conclusion are presented comprising suggestions for further work.