Seismic behavior of self-centering concrete-filled square steel tubular (CFST) Column Base

Traditional column base connections typically designed as fully restrained moment connections are questionable to be applied in self-centering seismic resisting structural systems. In this study, three types of self-centering concrete-filled square steel tubular (CFST) column base connections, i.e., Type I and Type II fabricated with post-tensioned (PT) strands and sandwiched energy dissipaters constructed in opposite and the same directions respectively and Type III fabricated PT strands and sandwiched energy dissipaters in orthogonal direction are proposed. Results shed light on the influence of these bases on seismic performance, beginning with a cyclic experimental investigation on three 3/4 scaled of Type I test specimens. Findings demonstrate that all test specimens exhibited typical flag-shaped hysteretic loops with the expected deformation mode, stable energy dissipated and good self-centering ability with 0.14% of the maximum recorded residual drift at 2% drift. Under 4% drift, the buckling restrained steel (BRS) plates yielded while the column and strands remained elastic, creating no damage to the main structural elements. Moreover, an analytical model of three types of self-centering CFST column base connections was developed, which are able to predict the column base connections moments reasonably. (C) 2019 Elsevier Ltd. All rights reserved.