Second-order analysis and design of steel structures allowing for member and frame imperfections

Conventional linear analysis is deficient in handling the design of slender frames since the effective length and other non-linear effects are difficult to assess accurately. Some proposed non-linear analyses cannot be directly employed for practical design since they are unable to re-produce the buckling curves of the basic structural element, a simple column under axial force, by a single element per member. This paper describes an advanced element, using the same physical significance as the advanced and second-order analysis proposed by a number of researchers and the BS5950(2000) and AS4100 (1995), for practical design of slender steel frames. The proposed element captures the physical behaviour of a structural member that the buckling strength of the member can be predicted using a single element per member and without assuming any effective length.