Behaviour and design of press-braked stainless steel angle and channel section members

• Main Author: Zhang, Lulu
• Other Authors: Zhao Ou
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Civil engineering::Structures and design
• Online Access: https://hdl.handle.net/10356/152431
• Institution: Nanyang Technological University

Growing focus has been put on the use of stainless steel members in constructional engineering, owing to the superior corrosion resistance and durability, high material strength and exceptional ductility, the nature of 100% recyclable and aesthetics of stainless steel compared to conventional carbon steel. Although extensive studies have been conducted on stainless steel structural members with doubly symmetric sections (such as square/rectangular/circular hollow sections and I-sections), there has been rather limited research on the behaviour of mono-symmetric sections (channel sections) and asymmetric sections (angle sections) to date. The focus of this thesis is thus the structural behaviour and design of stainless steel angle and channel section members subject to various loading conditions. A thorough experimental programme was firstly carried out on two press-braked equal-leg angle sections and two press-braked plain channel sections to obtain a test data bank. At the cross-sectional level, 8 stub column tests, 10 laterally restrained beam tests (about the geometric axes for angle sections and minor principal axes for channel sections), 20 combined loading tests (about the major and minor principal axes for channel sections) were conducted to study the local buckling behaviour of angle and channel section under pure compression, pure bending and combined loading, respectively. At the member level, 16 fixed-ended angle section column tests, 12 pin-ended channel section column tests and 10 channel section beam-column tests were conducted to study the flexural-torsional buckling behaviour of angle section columns, flexural buckling behaviour of channel section columns and global buckling behaviour of channel section beam-columns, respectively. The experimental programme was accompanied by a parallel numerical modelling programme, including validation studies, where finite element models were developed and validated against the test results, and parametric studies, where the validated finite element models were employed to generate further numerical data over a wide range of cross-section dimensions, member effective lengths and initial loading eccentricities. The test and numerical data were then adopted to evaluate the accuracy of the relevant codified design rules and other recently developed design approaches. It was generally found that the design codes lead to conservative cross-section resistance predictions, but scattered member resistance predictions, with both unsafe and conservative results, mainly attributed to the neglect of the pronounced material strain hardening effect and nonlinear material property of stainless steel in the design. Improved design methods were also finally proposed accordingly, offering more accurate and less scattered resistance predictions.