Numerical assessment of an enhanced stiffened extended end-plate joint for composite frame structures

Abstract

This paper presents the numerical assessment of a novel enhanced Bolted Stiffened Extended End-Plate (BSEEP) connection for steel frames with composite beams and H-shaped columns in the strong direction. Strain demand is a critical local response that directly controls rupture initiation, and it is more crucial in composite beams since the neutral axis shifts upwards due to the composite action. The proposed connection, called URBS-BSEEP, employs a reduced section in the beam upper flange to mitigate the strain demand problem and provide a stable and symmetric plastic hinge in the desired location. Nonlinear FEM is employed to study joint cyclic behavior. Eleven specimens are designed to compare the proposed connection with existing configurations and to investigate the effects of the slab isolation from the column, shear stud removal, reduced section geometry, and slab thickness. Hysteresis curves, ductilities, failure modes, strain profiles, and energy dissipation capacities are compared. The results indicate the superior performance of the connection compared to the conventional counterparts.