Bearing failure in stainless steel bolted connections

Although the mechanical behaviour of stainless steel and carbon steel differs significantly, design provisions for stainless steel connections in current standards are essentially based on the rules for carbon steel. For bolted connections, the design resistances in EN 1993-1-4 and the SCI/Euro Inox Design Manual for Structural Stainless Steel are based on those in EN 1993-1-8 and EN 1993-1-3 with only some minor modifications. In this paper, an investigation into the bearing behaviour of stainless steel connections between both thick and thin plates has been conducted. Numerical models for previously tested specimens in austenitic and ferritic stainless steel have been developed and validated. The validated models were then used to perform parametric studies to investigate the key variables affecting the bearing failure of bolted connections; these include edge distance e₂, end distance e₁ and plate thickness t. The investigation showed the deformation behaviour of stainless steel connections to be somewhat different from that of carbon steel connections, with stainless steel exhibiting pronounced strain hardening. However, the locations of fracture initiation obtained from the numerical models matched those observed during experimental studies of both carbon steel and stainless steel connections and this feature has been used as the basis for defining a consistent, strength based criterion of failure. The results of the parametric studies have been utilised as the basis for design provisions for bearing failure in stainless steel bolted connections that cover both the ultimate and the serviceability limit states and which are both more economic and more straightforward than the present EC3 provisions.