Second-order Direct Analysis of Steel Structures made of tapered members

Abstract

Mild steel hot-rolled sections are commonly prismatic because of the rolling process with a furnace, but welded sections made from steel plates do not have such a constraint, especially when robotic welding machines are used. The weight saving could be very significant by, say, using wide flanged section at mid-span and a small flanged section at ends of a simply supported beam. However, design codes do not provide formulae for buckling check of tapered members. This paper proposes a code-free second-order direct analysis for stabilty design of steel frames made of tapered members. The design is further applied to a single layered mega space frame of 136m span. In the whole design process based on the concept of Second-order Direct Analysis, no uncertain effective length and independent member buckling checking are required.

Design of web-tapered steel I-section members by second-order inelastic analysis with strain limits

“…In this study, the finite element analysis package Abaqus [50] was used to carry out the GMNIA simulations. A common method for analysing tapered members is to divide them into a sufficient number of prismatic segments [22]; at least twenty is recommended [51]. Although the influence of the inclined flanges of the tapered members on their internal stress distributions is neglected in this approach, it has been established that, for tapering angles typically encountered in practice (<15°), this influence is negligible and, hence the in-plane behaviour of tapered steel members can be accurately modelled using a series of prismatic beam elements [10].…”