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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]

• The compressive behaviour of square RACFSST stub columns after exposure to fire is investigated. • Twelve post-fire compression tests are conducted. • The influences of heating durations and RCA replacement ratios are discussed. • Thermal and mechanical FE models are validated against test results and then used to conduct parametric studies. • The relevant design codes are assessed against the test and FE data. Experimental and numerical studies on the cross-section compressive behaviour and residual resistances of square recycled aggregate concrete-filled stainless steel tube (RACFSST) stub columns after exposure to fire are reported in this paper. An experimental programme was firstly carried out on twelve stub column specimens with three recycled coarse aggregate replacement ratios (0%, 35% and 70%) after exposure to the ISO-834 standard fire for 0 min (i.e. at ambient temperature), 15 min, 30 min and 45 min. The test results, including load–end shortening curves, failure loads and failure modes, were presented, with the initial compressive stiffness and confinement effect analysed. The experimental programme was followed by a numerical modelling programme, where thermal and mechanical finite element models were developed and validated against the test results and afterwards used to conduct parametric studies to generate additional numerical data over a wide range of cross-section dimensions. Based on the test and numerical data, the relevant design rules for square natural aggregate concrete-filled carbon steel tube stub columns at ambient temperature, as specified in the European code, Australia/New Zealand standard and American specification, were evaluated, using post-fire material properties, for their applicability to square RACFSST stub columns after exposure to fire. The evaluation results generally revealed that the European code and Australian/New Zealand standard led to a good level of design accuracy, while the American specification resulted in slightly conservative post-fire cross-section compression resistance predictions. [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]

This paper presents experimental and numerical investigations into the post-fire cross-section compressive behaviour and resistances of circular recycled aggregate concrete-filled stainless steel tube (RACFSST) stub columns. Twelve stub column specimens, fabricated from concretes with three recycled coarse aggregate replacement ratios (0%, 35% and 70%), were tested after exposure to the ISO-834 standard fire for 0 min (i.e. at ambient temperature), 15 min, 30 min and 45 min. The experimental investigation included heating and cooling of specimens, cylinder tests and post-fire tensile coupon tests and stub column tests. The test results, including load–end shortening curves, failure loads and failure modes, were fully reported and the initial compressive stiffnesses and confinement effect were discussed. The numerical investigation was subsequently conducted, where thermal and mechanical finite element models were developed and validated against the test results and then used to perform parametric studies to generate further numerical data. Given the absence of design codes for stainless steel–recycled aggregate concrete composite structures after exposure to fire, the relevant design rules for circular natural aggregate concrete-filled carbon steel tube stub columns at ambient temperature, as set out in the European code, Australia/New Zealand standard and American specification, were assessed, using post-fire material properties, for their applicability to circular RACFSST stub columns after exposure to fire, based on the test and numerical data. The assessment results generally revealed that the European code and the Australian/New Zealand standard led to an acceptable level of design accuracy and consistency, while the American specification resulted in rather conservative and scattered post-fire cross-section compression resistance predictions. • The compressive behaviour of circular RACFSST stub columns after exposure to fire is investigated. • Post-fire compression tests on twelve circular RACFSST stub column specimens are conducted. • The influences of heating durations and RCA replacement ratios are analysed. • Thermal and mechanical FE models are validated against test results and then used to conduct parametric studies. • The relevant design codes are assessed against the test and FE data. [ABSTRACT FROM AUTHOR]

This paper reports experimental and numerical investigations into the structural behaviour and resistances of high strength concrete-filled stainless steel tube (HCFSST) beam-columns under combined compression and bending. An experimental investigation was conducted on sixteen HCFSST beam-columns specimens fabricated from stainless steel tubes with two cross-section sizes and high strength concretes with four material grades, and included concrete cylinder tests, tensile coupon tests, initial global geometric imperfection measurements and eccentric compression tests. The test setups and procedures were fully reported and the experimental observations were discussed and analysed in detail. It was found that the plane cross-section assumption was valid for eccentrically loaded HCFSST sections and the lateral deflection distribution patterns for HCFSST beam-columns were approximately half-sine wave shapes. The test results were used in a subsequent numerical investigation for the validation of finite element models, which were then employed to conduct parametric studies to generate additional numerical data over a wide range of cross-section dimensions, member lengths and loading combinations. Based on the experimental and numerical results, the relevant design rules, as set out in the European code, American specification and Australian/New Zealand standard, were evaluated for their applicability to HCFSST beam-columns. The evaluation results revealed that the European code provided accurate but scattered failure load predictions when used for HCFSST beam-columns, while the American specification and Australian/New Zealand standard resulted in conservative and scattered failure load predictions. • The behaviour of high strength concrete-filled stainless steel tube (HCFSST) beam-columns is investigated. • Eccentric compression tests on sixteen HCFSST beam-column specimens are conducted. • The ductility, strength, longitudinal strain development and lateral deflection distribution are analysed. • FE models are developed to validate against the test results and then used to conduct parametric studies. • The applicability of relevant design codes is assessed against test and FE data. [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]