Connection behavior of CFST column-to-beam joint implanted by steel rebars under cyclic loading.

• Four specimens were conducted under the cyclic loadings. • Transfer sleeves could improve the seismic behavior and restrain excessive deformation. • The outer annular stiffeners had limited contribution to the deformation of joints. Based on the cyclic loading of four concrete-filled steel tube (CFST) column-to-beam joints implanted by steel rebars, the paper studies the effects of different sectional sizes of middle columns and the configuration of transfer sleeve on the connection behavior. The failure mode, hysteretic behavior, skeleton curve, stiffness degradation, bearing capacity degradation, energy dissipation capacity, and strain distribution of all specimens were analyzed. The results showed that the plastic deformation was mainly concentrated at the column-column connections, especially at the upper-middle column connection. The cross-sectional dimensions of the middle column had a slight effect on the bending capacity of the connection, while the transfer sleeve enhanced on it. The outer annular stiffeners and webs bolted with the steel beam had limited contribution to the deformation of column-to-beam joints. [ABSTRACT FROM AUTHOR]