Local buckling and capacities of stainless steel hexagonal hollow sections under axial compression

•The compressive behaviour of stainless steel hexagonal hollow sections is investigated.•Fifteen stainless steel hexagonal hollow section stub column tests are conducted.•FE models are developed and validated against the test results and then used to conduct parametric studies.•The relevant design codes are assessed against the test and FE data.•An improved design approach is proposed. This paper presents experimental and numerical investigations into the local buckling behaviour and capacities of stainless steel hexagonal hollow sections. A testing programme, including tensile coupon tests, initial local geometric imperfection measurements and fifteen stub column tests, was firstly carried out. The key test results, including failure loads, load–end shortening curves and failure modes, were reported. Subsequently, a numerical modelling programme was conducted, where finite element models were developed and validated against the test results and then used to conduct parametric studies to generate additional numerical data. The obtained test and numerical data were used to evaluate the relevant local buckling design rules specified in the European code, American specification and ASCE standard. The evaluation results revealed that the slenderness limits, as defined in the European code and American specification, were generally accurate and safe when used for cross-section classification of stainless steel hexagonal hollow sections, while the ASCE slenderness limit was unsafe. The European code and American specification resulted in overall accurate and consistent cross-section compression resistance predictions, but the predictions for non-slender cross-sections were conservative and scattered, due to the neglect of material strain hardening. The ASCE standard led to overall scattered and relatively conservative cross-section compression resistance predictions, but also with some unsafe predictions for those intermediate cross-section sizes due mainly to the unsafe slenderness limit. Finally, a revised ASCE design approach was proposed and shown to result in more accurate predictions of cross-section classification and resistances.