FE modelling of bolted steel end-plate moment connections subjected to a standard fire

In fire conditions, the prediction of the behaviour of bolted steel connections becomes complicated since different parameters, such as temperature increase, beam thrust and large deformations, influence their structural behaviour. Finite-element modelling can help to better understand the three-dimensional deformations and the failure mechanisms of bolted connections at elevated temperatures. In this paper, a 3D finite-element modelling study of bolted end-plate moment connections subjected to elevated temperatures is presented. The modelled connections can be used to connect either tubular or I-shaped steel beams to tubular steel columns. The different components of the beam-to-column connection include the beam, column, beam end plate, column connecting plate, bolts and welds. The connection components were modelled using eight-node continuum hexahedral brick elements (C3D8R in ABAQUS/Standard V6.92 terminology), which have the capability of representing large deformations and the non-linearity of both geometry and material at elevated temperatures. Contact between the connection components was modelled using the surface-to-surface interaction command with a small sliding option. The model was validated using the experimental results of two full-scale fire-resistance tests. Good agreement between the model predictions and the experimental results was achieved for different measurements; such as the connection deformations, connection hogging moment, beam thrust and beam deflection.