Block shear behaviour and design of cold-formed staggered hole bolted connections

Abstract

Block shear strength of cold-formed steel bolted connections has been thoroughly investigated in the literature, although the behaviour of block shear with staggered holes has not been studied in detail. It is more complex and apparent that a combination of tension and inclined shear behaviour due to the presence of the staggered holes affects the shear strength and behaviour of the bolted connections. This paper presents an experimental program on the block shear behaviour of staggered hole bolted connections to provide a better understanding on the failure modes. A total of 24 tests using G450 sheets was conducted at the University of Sydney with 1.9 and 2.4 mm thicknesses. Digital Image Correlation (DIC) was employed to capture both the full field of the displacement and the block shear failure mode of the staggered hole bolted connections during testing. A comparison of the experimental strength with existing design equations for block shear with staggered holes in AISI S100:2016 and AS/NZS 4600:2018 is included in the paper. A calibrated Finite Element Model is then developed by the commercial program ABAQUS to validate against the test results and to further provide detailed insights which could not be seen in actual tests (i.e, stress and strain distributions). In the FE simulation, to study the whole range of deformation of the staggered hole bolted connections (i.e., elastic, plastic and fracture stages), a plasticity model and a ductile damage model are applied to the cold-formed steel sheets to represent various stress states in the steel during failure.