Experimental Study and Finite Element Analysis on Ultimate Strength of Dual-Angle Cross Combined Section Under Compression

This paper investigates Q420 dual-angle cross combined section columns under axial and eccentric compression by conducting experiments. The specimen parameters, experimental setup, and test results are presented. It showed that local buckling occurred apparently for single internode specimens (lambda<35) under axial compression, while overall bending buckling appeared for others, and no torsional buckling occurred. The theoretical formulas on stability factor were derived by the energy approach. Non-linear finite element models considering residual stress were established using ANSYS which were verified by the corresponding experimental results. The parametric study was to evaluate the effects of slenderness ratio (lambda), width to thickness ratio of angles (b/t), the number of filled plate (n), load relative eccentricity (e) and the lateral support stiffness on the ultimate strengths of dual-angle cross combined section columns. Based on above analysis, the design equations are proposed by using curve fitting technique. It is shown from comparison between test results, finite element analysis and related specifications that the ultimate strength from theoretical formulas, proposed equations and finite element models are consistent with experiments results.