Behavior of concrete-filled steel tubular three-dimensional subassemblages

Abstract

Three-dimensional subassemblages consisting of a concrete-filled steel tubular column and four H-shaped beams were tested under a constant axial load on the column, constant beam loads in the minor direction, and alternately repeated beam shear in the major direction simulating the earthquake loading. The specimens were designed for two types of failure mode; shear failure of the beam-to-column connection panel, and flexural failure of the column. The paper presents the test results, and discusses the hysteretic behavior, the maximum strength, the energy dissipation capacity, and failure configuration of each specimen. It is concluded that the panel-failing specimens are more stable and exhibit more energy dissipation capacity compared with the column-failing specimens, the strength of the panel-failing specimen exceeds the calculated strength and reaches the strength corresponding to the column failure, although the connection panel yields in shear, and the specimen subjected to the bi-axial bending in the column becomes unstable due to excessive deformation of a doglegged shape in the minor direction.