Seismic response tests and analytical assessment of blind bolted assembly CFST frames with beam-connected SPSWs

Abstract This paper presents a series of experimental and analytical studies to investigate the seismic behavior of blind bolted assembly concrete filled steel tube (CFST) frames with infill steel plate shear walls (SPSWs) connected to beam only. Two specimens of single-bay, two-story blind bolted assembly CFST frames with beam-connected SPSWs were fabricated and tested under lateral cyclic load combined with a constant vertical axial load. The test parameters include the column section type, the beam-SPSW connection type and the SPSW setting. Typical failure modes of the specimens were summarized and discussed. The test results show that the presence of SPSWs can compensate effectively the relatively small lateral stiffness of bare blind bolted CFST frames, and the novel SPSW-frame system exhibited good hysteretic performance, ductility and energy dissipation capacity. Moreover, the moments at the beam ends of a CFST frame with semi-rigid joints under two partial vertical loads resulting from the beam-connected SPSWs are derived. A practical design method for semi-rigid CFST frames with beam-connected SPSWs is summarized for checking the strength of blind bolted end plate joints, steel beams and CFST columns. The accuracy of the design method is also verified by the test results. The study shows that the novel SPSW-frame has good potential for application in earthquake resistant design of steel frame structures.