Cyclic testing of steel beam blind bolted to CFST column composite frames with SBTD concrete slabs

This paper aims to investigate the seismic behavior and failure mechanism of novel type of blind bolted concrete-filled steel tubular (CFST) composite frames under seismic loading. The composite frames are composed of square or circular CFST columns and steel-concrete composite beams with steel-bars truss deck (SBTD); the steel beams and the CFST columns are assembled by blind bolts and end plates. The failure modes, hysteretic behavior, strength and rigidity degradation, ductility and energy-dissipating performance of all specimens were analyzed and discussed. The influence of composite action of the floor slab on the performance of blind bolted CFST composite frames were also explored under seismic loading. The experimental results showed that the blind bolted CFST composite frames with the SBTD concrete slabs exhibited good hysteretic behavior, large ductility and high energy dissipation. The stiffness and strength of the frame increased greatly with the presence of the SBTD concrete slab. These test studies could promote the engineering design and application of the blind bolted CFST composite frames.