Behaviour and design of hot-rolled stainless steel channel section members

• Main Author: Li, Shuai
• Other Authors: Zhao Ou
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Civil engineering::Structures and design
• Online Access: https://hdl.handle.net/10356/168495
• Institution: Nanyang Technological University

Stainless steel offers numerous advantages over carbon steel, including superior corrosion resistance, high material strength and exceptional ductility. Therefore, the use of stainless steel members in civil and offshore engineering becomes increasingly prevalent. Channel sections with simple geometry are widely used in structural applications. This thesis is focusing on the structural behaviour and design of hot-rolled stainless steel channel section members subjected to various loading conditions. An experimental programme adopted grade EN 1.4301 austenitic stainless steel and four hot-rolled stainless steel plain channel sections: C 80×40×5, C 100×50×5, C 100×50×6 and C 150×75×6. Material testing was performed to measure the material stress–strain responses and membrane residual stress measurements were carried out to determine the membrane residual stress distributions and amplitudes in the studied hot-rolled stainless steel channel sections. At cross-sectional level, six stub column tests and twenty eccentrically loaded stub column tests about the major and minor principal axes were performed to investigate the local buckling behaviour of channel sections under isolated and combined loadings, respectively. At member level, ten column tests and ten beam-column tests were conducted to study the flexural buckling behaviour of channel section columns and global buckling behaviour of channel section beam-columns, respectively. The experimental programme was supplemented by a numerical modelling programme, where finite element models were initially developed and validated against the test results and then adopted to perform parametric studies to generate further numerical data over a wide range of cross-section dimensions, member effective lengths and loading combinations. The obtained experimental and numerical data were then employed to assess the accuracy of the existing design rules for hot-rolled stainless steel channel section members, as given in the European code and American specification. The assessment results revealed that the current design codes result in conservative cross-section resistance predictions, but scattered member resistance predictions with both conservative and unsafe results, mainly owing to the lack of proper consideration of the pronounced material strain hardening and nonlinear material property of stainless steel in the design. To overcome these shortcomings, new design approaches were proposed and shown to lead to a much higher level of design accuracy and consistency over the existing design standards. The reliability of the proposed design methods was demonstrated by means of statistical analyses, showing their suitability for incorporation into future revisions of international design codes for stainless steel structures.