Postbuckling Shear Capacity of External Diaphragm Connections of CFST Structures

Abstract

This paper presents experimental and analytical studies on the seismic behavior of beam-to-column connections with external diaphragms in the concrete-filled steel tubular (CFST) structures. Three cruciform joints between CFST column and H-shaped steel beam were tested subjected to a constant axial load on the column and a set of antisymmetrical cyclic loads at the beam’s tips to investigate the seismic behavior of the panel zone. A weak panel zone was specially considered in all three specimens to investigate the shear capacity of the panel zone. Key variables involved are the compressive strength of concrete and the axial load ratio. Three specimens all exhibited a shear failure in the panel zone due to local buckling. The strain distribution and load-displacement behaviors were discussed. In the analytical study, a computational model for the postbuckling shear capacity of panel zone was developed and checked for its applicability.