Compression performance of L-shaped multi-limb assembled cold-formed thin-walled steel concrete composite column

The modular wall light steel concrete composite frame structure is a novel load-bearing skeleton in ultra-low energy consumption prefabricated building systems. This study delves into the mechanical performance of L-shaped composite special-shaped columns within this system. Given that the mechanical behavior of L-shaped composite special-shaped columns under axial and eccentric compression remains unclear, nine groups of multi-limb assembled cold-formed thinwalled steel concrete L-shaped composite column (MCTSC-LCC) specimens were designed and experimentally tested. The experimental results indicate that the L-shaped composite columns exhibit excellent load-bearing capacity and stiffness characteristics. Furthermore, based on the experimental conditions and results, finite element methods were employed to simulate the Lshaped composite columns. By comparing the experimental data with the simulation results, the accuracy and reliability of the finite element model were validated. Based on this validated model, 542 groups of numerical simulations were conducted to thoroughly investigate the effects of parameters such as concrete strength, slenderness ratio, eccentricity angle, the thickness and strength of C-shaped steel on the load-bearing capacity, stiffness, and ductility of the components. The analysis results reveal the significant influence of these parameters on the performance of the components. Finally, this study proposed calculation formulas for the axial and flexural loadbearing capacity of L-shaped composite columns and developed a simplified calculation method for eccentric compressive bearing capacity based on these formulas. The accuracy of the proposed method was validated by comparing them with finite element simulation results, with the error within 10 %. To address the local discrepancies observed between the fitted curves and experimental data within the range from 0.92Nu to Nu, a local correction scheme was proposed, ensuring the applicability and accuracy of the calculation formulas across the entire domain.