Pseudo-dynamic tests of assembly blind bolted composite frames to CFST columns

This paper presents the dynamic response and failure mechanism for the novel assembly of blind-bolted concrete-filled steel tubular (CFST) composite frames with steel-bar truss deck (SBTD) concrete slabs under seismic action. With this type of composite frame, the SBTD concrete slabs are attached to H-shaped steel beams using shear connectors, and the steel-concrete composite beams are connected to CFST columns using flush or extended end plates with blind bolts. A series of pseudo-dynamic tests (PDTs) were conducted on two two-story one-bay composite frames with square or circular section CFST columns. The time-history response and inter-story drift of each test specimen were investigated to analyse the dynamic response of the composite structures under a series of ground motion records. Meanwhile, the seismic behaviour of the composite structures was also evaluated in terms of their failure modes, hysteretic behaviour, ductility, and strain response. The test results indicate that the structural response under a simulated seismic loading is consistent with the desired performance under different earthquake hazard levels. The proposed blind-bolted square or circular CFST composite frame, which exhibits excellent seismic behaviour and ductility, can be used as a reliable and effective assembly composite structure in seismic regions.