Press-braked S690 high strength steel equal-leg angle and plain channel section stub columns: Testing, numerical simulation and design

This paper reports an experimental and numerical investigation into the cross-section behaviour and compression resistances of press-braked 5690 high strength steel angle and channel section stub columns. The experimental study was carried out on four equal-leg angle sections and eight plain channel sections with a range of cross-section sizes (covering both non-slender and slender sections), and included thirty-six material tensile flat and corner coupon tests, initial local geometric imperfection measurements and twenty-four concentrically loaded stub column tests. The experimental study was then supplemented by a numerical modelling programme, where numerical models were firstly developed to simulate the test structural responses and subsequently adopted to derive further numerical data. The experimentally and numerically derived results were utilised to assess the applicability of the Eurocode Class 3 slenderness limits for hot-rolled and welded sections to their cold-formed (press-braked) counterparts. The results of the assessment generally revealed that the Eurocode Class 3 slenderness limits for hot-rolled and welded sections can be safely adopted for the classification of press-braked (cold-formed) 5690 high strength steel angle and channel sections subjected to compression. The accuracy of the codified design provisions established in Europe, North America and Australia/New Zealand as well as the direct strength method (DSM) to the design of press-braked 5690 high strength steel angle and channel section stub columns was also assessed, based on the test data and numerical results. The North American, Australian and New Zealand standards were found to result in accurate and consistent compression capacity predictions for press-braked 5690 high strength steel channel section and non-slender angle section stub columns, but greatly underestimate the compression capacities for those slender angle section stub columns, while the European code and DSM were shown to yield overall precise and consistent design compression capacities.