Equivalent slenderness ratio for built-up members

Abstract

Built-up struts that buckle about an axis perpendicular to the plane of the connectors should be treated as a "built-up" member as opposed to a "simple" member. This mode of buckling causes shear and moments in the connectors which deform the connectors. These deformations increase the lateral deformation of the member and hence affect the load-carrying capacity. To account for this effect the easiest method is to use an equivalent slenderness ratio such as the one included in the Canadian Standard. This note outlines the derivation of the equivalent slenderness ratio equation, discusses when it should and should not be used, and includes a numerical example. A rewording of the applicable clause in the Canadian Standard is suggested. Key words: battens, built-up members, connectors, slenderness ratio.

Experimental investigation of built-up cold-formed steel section battened columns

“…The investigation highlighted the design of built-up battened double-angle columns. Temple and Elmahdy [7,8] discussed the buckling mode of built-up carbon steel columns. In the study [7], the authors proposed a brief derivation of an equivalent slenderness ratio equation and its applicability.…”

“…Temple and Elmahdy [7,8] discussed the buckling mode of built-up carbon steel columns. In the study [7], the authors proposed a brief derivation of an equivalent slenderness ratio equation and its applicability. While the study [8] showed that nondimensional slenderness ratio of main column components between connection points had a significant effect on the column strength and buckling behaviour.…”

Investigation on slenderness ratios of built-up compression members

“…Zahn and Haaijer [12] determined the number of connectors and the accompanying design strength for double-angle columns. Temple and Elmahdy [13] investigated the buckling mode of built-up member. Their paper also shows the derivation of the equivalent slenderness ratio equation and its applicability.…”

Instability behavior and application of prismatic multi-tube latticed steel column

“…Substantial investigation on built-up columns has been mostly focused on the in-depth study of conventional built-up columns, of which the branch components are channel-section and I-section [13][14][15][16][17]. Detailed research was conducted by Lue [18] and a comparison of slenderness ratios specified in various design codes was provided.…”