To investigate the influence of reinforcement cages and circular steel tube on special-shaped multi-cell concrete-filled steel tube (SMCFST) under reciprocating axial load
three large-size specimens were designed based on Z15 tower. The failure model
load-deformation curves
skeleton curves
bearing capacity
deformation capacity
stiffness degeneration
cumulative energy dissipation
and strain of the specimens were analyzed. Codes of different nations were utilized to calculate the bearing capacity of the specimens. The results shown that the reinforcement cages could enhance the initial stiffness and bearing capacity of the specimens. The circular steel tube could further improve the initial stiffness and bearing capacity
as well as significantly enhance the ductility
cumulative energy dissipation
and the behavior of the specimens at the later stage. Moreover
since the codes ignored the effect of horizontal diaphragms and the different buckling mechanisms between inner steel plate and outer steel plate
the calculation results were significantly lower than the experimental results. Therefore
it was necessary to further investigate the calculation method of the multi-cell concrete-filled steel tube. The circular steel tube was suggested to be used in buildings to improve the axial compression behavior of the special-shaped multi-cell concrete-filled steel tube.