Axial stiffness prediction of non-preloaded T-stubs: An analytical frame approach

The prediction of the behaviour of beam-to-column bolted connections can be carried out by means of the component method, adopted by Eurocode 3, which accounts for any bolted connection typology, provided that the basic components are identified and modelled. Many of these components are represented using the so-called equivalent T-stub.In this paper, an equivalent frame model is presented for the T-stub to predict the axial stiffness, designed for hand calculation. The response is calculated analytically on the basis of a beam assembly representation for the flanges and the bolts of the T-stub. Compatibility requirements and prying forces are taken into account. In addition, an advanced finite element model of a representative T-stub test is proposed. This FE model has been developed in order to characterize the deformation response and the distance between the plastic hinges in the T-stub flange. Furthermore, an effective width for stiffness calculation is suggested, based on a plate finite element parametric study. Results are validated by comparison with experimental data from the literature, proving the importance of considering the actual value of prying forces.