Stainless steel is used widely across a range of industries due to its favourable structural properties, excellent corrosion resistance and fire resistance. Stainless steel structural design standards have generally been developed based on assumed analogies with carbon steel design. Consequently, resulting design solutions can be inaccurate and overly conservative due to the rounded nature of the stress–strain curve not being suitably reflected. The nonlinear material stress–strain response has a direct influence on the structural behaviour of stainless steel and it is fundamental that a design methodology reflects this. With an emphasis on frame level design, a series of proposals are made in this thesis to enable the safe and efficient assessment of stainless steel structures. A number of the proposals are also applicable to carbon steel design. The issue of overall frame stability in the inelastic regime is first addressed. An approach to allow for the premature loss of stiffness due to material nonlinearity is developed and a modified elastic buckling load factor method is proposed to account for the increased global second order effects. The modified critical load factor takes account of the reduced stiffness of the frame due to plastification and can be applied to both carbon steel and stainless steel frames.
The opportunities offered through design by advanced (second order inelastic) analysis are then explored. This approach is particularly suited to stainless steel because of the design complexities that arise from the rounded material stress–strain response. The key components required for the design of stainless steel structures by advanced analysis are developed herein. The new method employs computationally efficient beam elements yet safely captures cross-section failure by utilising strain limits defined through the continuous strength method (CSM). The CSM strain limits simulate the effects of local buckling and control the extent to which plasticity, moment redistribution and strain hardening can be exploited. The practical application of the proposed method is facilitated through the development of equivalent bow imperfections derived specifically for design by second order inelastic analysis. The proposed method is applied to both individual members and systems and is shown to provide consistent and significant benefits over current design methodologies.