Nonlinear response of coupled and tied-to-rigid base T-stub connections

Coupled and tied-to-rigid base T-stub connections are characterized by different evolution of the damage pattern at large imposed deformations. Thus, experimental tests and numerical analyses have been carried out to investigate the reasons causing such differences. The experimental campaign comprises two tests that were conducted on a coupled and a tied-to-rigid base T-stub specimen. The experimental results were used to validate finite element (FE) models that were used to investigate the local response of the tested specimens. Moreover, parametric FE analyses were carried out to examine the influence of the (i) flange thickness, and (ii) bolt-to-web distance. The obtained results confirm that coupled and tied-to-rigid base T-stub connections have different ultimate responses, especially in terms of force–displacement response curves, failure modes, and plastic demand in the bolts. In this regard, considerable shear force in the bolts was observed in the tied-to-rigid base T-stub connections with thin flange (i.e., nominally designed to experience mode 1) at large imposed deformations, thus leading to anticipate the failure of the bolts with respect to the corresponding coupled T-stub connections