To study the mechanical properties and design method of CFST columns with special-shaped cross-section

based on the special-shaped multi-cell CFST bifurcated columns of a super-high building under construction in Beijing

the FEM analysis on the seismic behavior of the special-shaped concrete-filled bifurcated steel tube columns was carried out. The test parameters were the different constructional measures

different steel and concrete grades. The results show that the developed FEM analysis method has adequate accuracy compared with the test results. The seismic behavior of the columns increased with increasing the number of the cells

the installation of the stiffener

L-type steel and steel tube. Increasing the number of the cavities has a better effect on seismic behavior than the increasing thickness of the steel tube in the case of the same steel consumption. The materials strength has a great influence on the seismic performance of the bifurcated column

and the strength matching between the steel and concrete should be considered in seismic design.