Experimental studies on through-plate moment connection for beam to HSS/CFT column

Abstract

A new moment connection for a steel beam to hollow structural section (HSS) and concrete-filled tube (CFT) columns using the through-plate technique is proposed. In the through-plate connection, all the demands of the beam are initially transferred to a vertical plate by in-plane action and are subsequently transferred to a column. Three full-scale interior planar connections are loaded cyclically under displacement control as per the AISI/AISC341-16 loading protocol. An axial compression force corresponding to 10% of the column axial capacity is applied to the column. The goals of the experimental study are as follows: (1) to evaluate the connection performance under cyclic loading and (2) to evaluate the connection components for extracting key design parameters. Square-shaped HSS sections with electric resistance welding are utilized for the column. To investigate the effect of concrete infill on the connection performance, the HSS column and one of the CFT columns are constructed using the same steel tube. The width-to-thickness ratio (b/t) for the corresponding specimens is 27, and another CFT specimen with a higher ratio of 34.5 is considered. In all the specimens, the plasticity is concentrated in the beam hinges, without any damage to the column or connection components. The proposed connection exhibits extremely high strength, stiffness, and ductility and is categorized as a rigid connection. Additionally, it exhibits stable cyclic behavior and high energy dissipation up to a story drift of at least 6% and satisfies the AISC seismic provisions as a special moment connection.