Flexural performance of self-compacting lightweight fibre-reinforced concrete-filled cold-formed steel battened built-up columns along weak axis

Abstract

In reference to the partially encased concrete (PEC) construction methodology, we propose an innovative method, which uses fibre-reinforced self-compacting lightweight aggregate concrete (FSLC) to fill cold-formed steel battened built-up columns to improve the buckling resistance of light gauge steel components. The eccentricity distance serves as a parameter for investigating the mechanical properties under eccentric loading of this novel combined column. We analyze the compressive damage mode of the combined column to elucidate the strain development patterns across its cross-section under varying eccentric loads. The findings indicate that the damage pattern exhibited by this new composite column under eccentric loading closely resembles that of traditional reinforced concrete columns. Prior to reaching 80 % of peak load (N ≤ 0.8 N_u), longitudinal strains along the height of the damaged section are predominantly linear, aligning with flat section assumptions; finite element simulations indicate growth in the tensile stress area of damaged concrete sections with increasing eccentricity; upon failure, compressive stress in the concrete follows a parabolic distribution along its weak axis, while the stress distribution within the light gauge steel framework mirrors that of PEC columns with minor eccentric compression damage.