Experimental and Numerical Investigations on Strength of Eccentrically Loaded Steel Square Hollow Sections

Abstract

This paper aims at studying the behavior and design of: slender and non-compact steel square hollow sections, SHS, under eccentric loading where both experimental and numerical approaches are used. Seven experimental tests are carried out on SHS with different eccentricities (e), slenderness ratios (ƛ), and width-to-thickness ratio (b/t). Numerical simulations of tests are carried out using the general purpose finite element program, ANSYS V.17. Geometrical and material non-linarites are considered in the numerical model. Geometric imperfections are included in the numerical model by altering nodal co-ordinates from perfect configuration. The amplitude of geometric imperfection is limited by acceptable tolerances stipulated by ASTM A500 whereas the shape of the geometric imperfection is obtained by combining local buckling and global flexural buckling mode shapes. Finite element results are verified by comparison to test results obtained herein. Assessment of numerical and test results obtained herein with current AISC code equations revealed compatibility of the current design equations with the test and numerical results for non-compact sections. However, for slender sections, the code equations are indeed conservative compared to test and numerical results by 40% in some cases especially at slenderness ratio, ƛ of less than 1.0. An extensive parametric study is conducted to investigate the effect of b/t, ƛ and e on the strength of SHS. The numerical results revealed that the current design equations for eccentrically loaded slender SHS must be revisited. A new set of design equations for eccentrically loaded SHS was proposed based on the test and numerical results. The proposed equations provided good representation of strength and behavior of slender eccentrically loaded SHS.