Stability and design of steel angle section members
File(s)
Author(s)
Behzadi-Sofiani, Behnam
Type
Thesis
Abstract
The stability and design of steel and stainless steel equal-leg angle section members with different loading and support conditions, including fixed-ended angles under axial compression and simply-supported angles under uniaxial bending, are addressed presently. First, elastic buckling behaviour is described; it is shown that torsional and local elastic buckling are similar in fixed-ended equal-leg angle section columns and equal-leg angles under minor-axis bending. In addition, it is shown that equal-leg angle section beams under minor-axis bending are susceptible to lateral-torsional buckling and Brazier flattening. An experimental investigation, comprising material testing, measurements of initial geometric imperfection and physical member tests, including 5 tests on fixed-ended hot-rolled stainless steel equal-leg angle section columns, 7 tests on hot-rolled steel and a further 7 tests on hot-rolled stainless steel equal-leg angle section beams, is then presented. The test results, in combination with existing experimental data on steel and stainless steel equal-leg angle section members collected from the literature, are then used for the validation of numerical (shell finite element) models, developed within the commercial package ABAQUS. Validation is performed by means of comparisons between test and numerical results, considering ultimate loads and failure modes, all of which are shown to be generally in good agreement. A numerical parametric study is then conducted considering both hot-rolled and cold-formed steel and stainless steel equal-leg angle section members with a wide range of cross-section geometries and member lengths. The behaviour and load-carrying capacity of the members is shown to be dependent on, not only the member slenderness, but also the ratio of the torsional-flexural to minor-axis flexural elastic buckling load and the local to lateral-torsional elastic buckling moment for columns and beams, respectively. Finally, on the basis of the above observations and data new design equations, suitable for incorporation into future revisions of Eurocode 3, for both steel and stainless steel equal-leg angle section members, are developed. It is demonstrated that the new proposals offer substantially improved accuracy and consistency in strength predictions compared to the existing codified design rules.
Version
Open Access
Date Issued
2021-09
Date Awarded
2021-12
Copyright Statement
Creative Commons Attribution Licence
License URL
Advisor
Gardner, Leroy
Wadee, Mohammad Ahmer
Publisher Department
Civil and Environmental Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)