Ultimate behaviour of bolted beam‐to‐column connections in large rotations

Abstract

AbstractThe capacity of steel Moment Resisting Frames (MRFs) to survive to extreme load is strictly linked to the moment‐rotation capacity of the beam‐to‐column connections. In those conditions, i.e., in extreme loading conditions, catenary actions develop in the connected beam leading in large joint rotations. The current European code, the Eurocode 3 Part 1‐8, neglects the regime of large joints rotations in the modelling leading to gross under‐ (or over‐) prediction of its response. In fact, recent works have shown that geometrical nonlinearity strongly influence the overall behaviour of connections when in large rotations range. To fill this knowledge gap, a mechanical model of a Double‐Split Tee Joint (DSTJ) that only considers material non‐linearity, is extended here to include geometric non‐linearity. To preliminary validate the mechanical model presented in the paper, an experimental test on a DSTJ has been performed and the result, both in terms of experimental data and mechanical prevision, has been compared. As a results, the updated mechanical model will be shown to be highly accurate in predicting the ultimate joint rotation (φ) and the maximum bending moment capacity (M) of the joint.