Seismic behavior of biaxial hollow reinforced concrete slab to concrete-filled steel tubular column connections

Abstract

This paper discusses the seismic behavior of biaxial hollow reinforced concrete (RC) slab to concrete-filled steel tubular (CFST) column connections. Seven scaled specimens were tested under cyclic loading, where the axial compressive load applied on CFST column was selected as the parameter. Both exterior and interior joints were investigated. Two types of failure modes, i.e., beam failure and column failure, were observed. For specimens with beam failure, the failures are mainly caused by the fracture of top steel beam flange. For specimens with column failure, the failures are primarily triggered by the buckling of tube wall. The proposed composite slim floor system inherently meets the principle of strong joint-weak member. The ultimate story drift of all specimens is 2.2-2.8 times of plastic drift ratio specified in codes, and the equivalent damping coefficient at peak loads ranges from 0.12 to 0.19, indicating the proposed composite slim floor system has a good seismic performance.