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• Twelve pin-ended compression tests on austenitic stainless steel flat–oval hollow section columns were conducted. • Their flexural buckling behaviour about the cross-section major and minor principal axes was studied. • FE models were developed to simulate the test results and then used to perform parametric studies. • The codified buckling curves were evaluated. The flexural buckling behaviour and resistances of cold-formed austenitic stainless steel flat-oval hollow section columns are studied in this paper, based on experiments and numerical modelling. An experimental investigation was firstly conducted and included tensile coupon tests, initial geometric imperfection measurements and major-axis and minor-axis pin-ended compression tests on ten column specimens. The experimental investigation was followed by a numerical investigation, where the column test results were used to validate finite element models; upon validation, parametric studies were conducted to generate additional numerical data over a wide range of cross-section dimensions and member effective lengths. The obtained test and numerical data were adopted to assess the applicability of the relevant buckling curves for cold-formed austenitic stainless steel circular and elliptical hollow section columns, as specified in the European code, American specification and Australian/New Zealand standard, to cold-formed austenitic stainless steel flat-oval hollow section columns. It was revealed from the assessment results that the buckling curves of the European code and American specification led to overall accurate and consistent flexural buckling resistance predictions, while the flexural buckling resistance predictions from the buckling curve of the Australian/New Zealand standard were slightly conservative. [ABSTRACT FROM AUTHOR]

• The flexural buckling behaviour of austenitic stainless steel semi-oval hollow section columns was studied. • Twelve pin-ended column tests were conducted. • FE models were developed to validate against the test results and then adopted to conduct parametric studies. • The codified buckling curves were evaluated and led to an overall good level of design accuracy. Semi-oval hollow section is an innovative cross-section profile and consists of one semi-circular flange, one flat flange and two flat webs. While the semi-circular flange (exposed to fluid or wind) offers a low level of hydrodynamic or aerodynamic drag, the flat elements facilitate connections with other members. The flexural buckling behaviour and resistances of austenitic stainless steel semi-oval hollow section columns are investigated in this paper. An experimental programme was firstly conducted on two austenitic stainless steel semi-oval hollow sections, with six column specimens of varying member lengths adopted for each cross-section, and included tensile coupon tests, initial geometric imperfection measurements and pin-ended column tests. Both 'C'-shaped flexural buckling (with failure specimens bowing towards semi-circular flanges) and 'reverse C'-shaped flexural buckling (with failure specimens bowing towards flat flanges) were observed upon testing. The experimental programme was accompanied by a numerical modelling programme, with finite element models developed to simulate the test results and then adopted to conduct parametric studies to generate further numerical data. On the basis of the test and numerical data, the relevant buckling curves for austenitic stainless steel circular hollow section columns, as provided in the European code, American specification and Australian/New Zealand standard, were evaluated for their applicability to austenitic stainless steel semi-oval hollow section columns. The evaluation results generally revealed that the codified buckling curves led to overall accurate and consistent flexural buckling resistance predictions when used for austenitic stainless steel semi-oval hollow section columns. [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical investigations into the web crippling behaviour and load-carrying capacity of stainless steel built-up I-section members under End-Two-Flange (ETF) concentrated transverse loading. An experimental programme was conducted on 23 austenitic and duplex stainless steel built-up I-section specimens, with each consisting of two identical press-braked channel sections assembled back-to-back by means of self-tapping screws. Following the experimental programme, a numerical modelling programme was performed, where finite element models were firstly developed to replicate the tests and then used to conduct parametric studies. Based on the test and numerical data, the existing design rules for stainless steel built-up I-section members failing by web crippling, as set out in the current European, American and Australian/New Zealand design standards, were assessed. The comparisons indicated that the European and Australian/New Zealand design standards resulted in overly conservative and rather scattered failure load predictions, while the American design standard led to less scattered failure load predictions, but with many predictions on the unsafe side. Therefore, an improved design approach was proposed and shown to provide substantially improved failure load predictions for stainless steel built-up I-section members under End-Two-Flange loading. • The web crippling behaviour of stainless steel built-up I-sections under ETF loading was studied. • Tests were conducted on 23 stainless steel built-up I-section specimens. • FE models were developed and validated against test results and then used for parametric studies. • The existing codified design rules were assessed and a new design approach was proposed. [ABSTRACT FROM AUTHOR]

The flexural buckling behaviour and resistances of press-braked stainless steel Z-section columns are investigated in this paper, based on experiments and numerical modelling. An experimental investigation was conducted on two press-braked stainless steel Z-sections and included material testing, initial geometric imperfection measurements and twelve fixed-ended column tests. Minor-axis flexural buckling was observed for all press-braked stainless steel Z-section column specimens upon testing. The key obtained fixed-ended column test results, including failure loads, load–deformation histories and failure modes, were fully reported. Following the experimental investigation, a numerical investigation was performed, with finite element models developed to validate against the fixed-ended column test results and then used to conduct parametric studies to generate additional numerical data. On the basis of the test and numerical data, the relevant buckling curves, as specified in the European code, American specification and Australian/New Zealand standard, were evaluated and shown to provide accurate and consistent flexural buckling resistance predictions for press-braked stainless steel Z-section columns. • The flexural buckling behaviour of press-braked stainless steel Z-section columns was studied. • Twelve fixed-ended column tests were conducted. • FE models were developed to validate against the test results and then used to perform parametric studies. • The codified buckling curves were assessed, showing good design accuracy and consistency. [ABSTRACT FROM AUTHOR]

• The structural behaviour of press-braked austenitic stainless steel slender channel section beam-columns was studied. • Ten beam-column tests were performed. • FE models were developed to simulate the test results and then adopted to conduct parametric studies. • The codified design interaction curves were assessed, indicating conservatism. • A new improved design interaction curve was proposed. The present paper reports experimental and numerical studies of the structural behaviour and resistances of press-braked austenitic stainless steel slender channel section beam-columns under combined compression and minor-axis bending. An experimental programme, including initial geometric imperfection measurements and ten beam-column tests, was firstly performed. The test procedures, setups and results were fully reported. The experimental programme was accompanied by a numerical modelling programme, including a validation study, where finite element models were developed and validated against the test results, and a series of parametric studies, where the validated finite element models were used to generate further numerical data. The obtained test and numerical data were adopted to assess the current design interaction curves for press-braked austenitic stainless steel slender channel section beam-columns, as provided in the European code, American specification and Australian/New Zealand standard. The assessment results revealed that all the three codified design interaction curves led to conservative and scattered resistance predictions, due to the conservative compression and bending end points and inappropriate shapes. To address these shortcomings, a new design interaction curve has been proposed and shown to yield a higher level of design accuracy and consistency for press-braked austenitic stainless steel slender channel section beam-columns than the codified design interaction curves. [ABSTRACT FROM AUTHOR]

• The structural behavior and capacity of RACFSST stub columns under combined loading are studied. • Twelve eccentric compression tests on RACFSST stub columns are conducted. • The evolution of neutral axis in RACFSST composite section as well as the confinement effect are discussed. • FE models are developed to validate against the test results and then used to conduct parametric studies. • The relevant design codes are assessed against the test and FE data. This paper reports experimental and numerical investigations into the behaviour and resistance of recycled aggregate concrete-filled stainless steel tube stub columns under combined compression and bending. Eccentric compression tests were conducted on twelve stub column specimens fabricated from austenitic stainless steel tubes with two cross-section sizes and concretes with three recycled coarse aggregate replacement ratios (0%, 35% and 70%). The test results, including the failure loads, load–mid-height lateral deflection curves, evolution of neutral axis and confinement effect, were discussed in detail. The testing programme was followed by a numerical modelling programme, where finite element models were developed and validated against the test results and then used to perform parametric studies to generate further numerical data over a wide range of cross-section dimensions and loading combinations. Given that there are no existing design codes for recycled aggregate concrete–stainless steel composite structures, the relevant codified design rules for natural aggregate concrete filled-carbon steel tube stub columns under combined compression and bending, as set out in the European code, American specification and Australian/New Zealand standard, were evaluated for their applicability to recycled aggregate concrete filled-stainless steel tube stub columns, based on the test and numerical data. The evaluation results revealed that the European code and Australian/New Zealand standard generally provide an acceptable level of design accuracy, while the American specification yields unduly conservative failure load predictions. [ABSTRACT FROM AUTHOR]

A series of tests on cold-formed high-strength stainless steel square and rectangular hollow sections subjected to web crippling is presented in this paper. The types of stainless steel investigated in this study were high strength austenitic and duplex material. The measured web slenderness value of the hollow sections ranged from 16.5 to 49.7. The tests were carried out under four loading conditions considered in the American Specification and Australian/New Zealand Standard for cold-formed stainless steel structures, namely end-one-flange, interior-one-flange, end-two-flange, and interior-two-flange loading conditions. The web crippling test strengths were compared with the design strengths obtained using the American, Australian/New Zealand, and European Specifications for stainless steel structures. In addition, the North American Specification for cold-formed carbon steel structural members was also used to predict the web crippling strengths and compared with the test results. It is shown that the design strengths predicted by the specifications are either unconservative or very conservative. Hence, a unified web crippling equation with new coefficients for cold-formed high strength stainless steel square and rectangular hollow sections is proposed in this paper. It is shown that the proposed web crippling equation is safe and reliable. [ABSTRACT FROM AUTHOR]

An experimental investigation of cold-formed stainless steel hollow sections subjected to web crippling is presented in this paper. Tests were conducted on square and rectangular hollow sections of austenitic stainless steel type 304. Tensile and compression coupon tests were performed to obtain the longitudinal tension and transverse compression material properties. The web crippling tests were conducted under two loading conditions for end-two-flange and interior-two-flange specified in the current American Specification and Australian/New Zealand Standard for cold-formed stainless steel structures. The test strengths obtained from this study and the test strengths of stainless steel lipped channel sections under end-one-flange and interior-one-flange loading conditions conducted by other researchers are compared with the design strengths obtained using the current American Specification, Australian/New Zealand Standard and European Code for cold-formed stainless steel structures. In addition, the test strengths are also compared with the design strengths obtained using the unified web crippling equation as specified in the North American Specification for cold-formed carbon steel structural members. A unified web crippling equation for cold-formed stainless steel sections with single web is proposed in this paper. [ABSTRACT FROM AUTHOR]

The present paper reports an in-depth testing and numerical modelling programme, to study the post-fire local buckling behaviour and residual resistances of austenitic stainless steel circular hollow section (CHS) stub columns under combined compression and bending moment. The testing programme employed twelve austenitic stainless steel CHS stub column specimens and included heating and cooling of the stub column specimens, post-fire material testing and post-fire combined loading tests. The testing programme was followed by a numerical modelling programme, where finite element models were developed and validated against the test results and then employed to perform parametric studies to generate additional numerical data. It is worth noting that there are currently no design standards established specifically for stainless steel structures after exposure to fire. In this study, the relevant design rules (i.e. cross-section interaction curves) for stainless steel CHS under combined loading at ambient temperature, as set out in the European, American and Australian/New Zealand standards and given in the continuous strength method, were assessed for their applicability to austenitic stainless steel CHS under combined loading after exposure to fire, based on the obtained test and numerical data. The results of the assessments revealed that all the codified design cross-section interaction curves have certain shortcomings, including the lack of rational exploitation of material strain hardening and the use of linear interaction, and thus yield excessively high degrees of conservatism and scatter when used for austenitic stainless steel CHS under combined loading after exposure to fire. The continuous strength method was shown to lead to accurate and consistent post-fire residual resistance predictions for austenitic stainless steel CHS under combined loading, due principally to the rational consideration of material strain hardening. Finally, the reliability of the continuous strength method was confirmed by means of statistical analyses. • The post-fire local buckling behaviour of stainless steel CHS under combined loading was investigated. • A total of twelve post-fire combined loading tests were conducted. • FE models were developed and validated against the test results and then used to perform parametric studies. • The applicability of the codified and CSM design cross-section interaction curves was assessed. [ABSTRACT FROM AUTHOR]

• The net section failure behaviour and capacity of stainless steel staggered botled connections are studied. • Tension tests on 31 stainless steel staggered bolted connections are conducted. • The influences of the staggered bolt hole pattern and pitches on the failure loads and modes are disscussed. • The accuracy of the codified design rules is assessed, indicating conservatism. • A new design approach based on the continuous strength method is proposed and results in substantially improved predictions. The present paper reports a thorough experimental investigation into the net section failure behaviour and capacity of stainless steel staggered bolted connections in tension. The testing programme was carried out on 31 stainless steel staggered bolted connection specimens, with 18 made of austenitic stainless steel (grade EN 1.4301), 7 made of duplex stainless steel (grade EN 1.4462) and 6 made of ferritic stainless steel (grade EN 1.4016). The geometric parameters, including the transverse and staggered pitches, and the staggered bolt hole patterns of the connection specimens, were varied. The test setup and procedures, as well as the key experimentally observed results, including the net section failure modes and loads, are reported in detail. The experimentally obtained net section failure loads and modes are analysed and discussed, and then utilised to assess the accuracy of the established design rules for stainless steel staggered bolted connections, given in the European, American and Australian/New Zealand standards. All three examined standards consider (i) net section fracture and (ii) gross section yielding in the design of stainless steel staggered bolted connections, and specify that the design failure load shall be taken as the minimum value calculated from all potential failure modes. It was found that the current design standards lead to overly conservative and scattered failure load predictions as well as inaccurate failure mode predictions. A new design approach based on the continuous strength method (CSM) is proposed, and shown to result in substantially improved predictions of both failure loads and failure modes. [ABSTRACT FROM AUTHOR]

The present paper reports experimental and numerical studies of the minor-axis flexural buckling behaviour and resistances of welded I-section columns made of a newly developed grade EN 1.4420 high-chromium austenitic stainless steel. The structural testing programme comprised ten pin-ended column tests as well as supplementary measurements of the initial global and local geometric imperfections of the column specimens. The structural testing programme was accompanied by a numerical modelling programme, including a validation study, where column finite element models were developed and validated against the experimental results, and a parametric study, where the validated column finite element models were employed to generate an additional numerical data bank over a broad spectrum of cross-section dimensions and member effective lengths. The obtained test and numerical data, were adopted to evaluate the applicability of the design provisions for normal stainless steel welded I-section columns, as set out in the current European code and American design guide, and cold-formed doubly symmetric section columns, as given in the existing Australian/New Zealand standard and American specification, to the new high-chromium stainless steel welded I-section columns. Overall, it was found that (i) all the four considered codes can be safely extended to cover the design of high-chromium stainless steel welded I-section columns, except for the American specification, which results in unsafe flexural buckling resistance predictions, and (ii) the most accurate and consistent design flexural buckling resistances were obtained by using the European code. • The flexural buckling behaviour of welded I-section columns made of a new high-chromium stainless steel were studied. • Ten pin-ended high-chromium stainless steel welded I-section column tests were performed. • FE models were firstly developed and validated against the test results, and then adopted to conduct parametric studies. • The applicability of the current codified flexural buckling design rules was evaluated. [ABSTRACT FROM AUTHOR]