Numerical Study on Ultimate Deformation and Resistance Capacity of Bolted T-Stub Connection

Disproportionate or progressive collapse is a phenomenon in which entire structure or large part of it collapses because of the local failure of a structure. Resistance to such progressive collapse depends on continuity between elements and ductility of the connections. The ductility of commonly used bolted end plate connections may depend on the T-stub component of the connection. The aim of this paper is to study the behaviour of T-stub components of beam to column end plate bolted connections under large deformation demands associated with column loss scenario. For this purpose, a parametric study is carried out to evaluate the ultimate strength and deformation capacity considering two parameters i.e. distance between the bolts and endplate thickness. Based on the experimental data, numerical model has been validated and employed in a parametric numerical study aimed at improving the response under large deformation demands. The study indicate significant role of bolts in development of catenary forces since the ultimate tensile capacity of T-stub after undergoing large deformation in a ductile failure mode was controlled by the failure of the bolts. Parametric study reveals much higher bolt force in comparison with displacement controlled induced axial force in the T-stub indicating failure of the bolts at much lower applied axial force.