Abstract：In order to study the influence of cross-sectional constructions on seismic behavior of special-shaped CFT columns with multiple cavities in the long axis direction, five specimens were tested under the axial compression and twice loaded low-cyclic horizontal loads. There are one basic construction and four enhanced constructions in the cross-sectional constructions. The four enhanced constructions include the enhancement of increasing the thickness of the longitudinal steel plate in the lower layer of the lower column under bifurcate plane and the upper column, the enhancement of adding the cavities at the lower layer under bifurcate plane, and the enhancements of additionally installing steel angles or steel tubes in the corner cavities apart from the enhancement of adding the cavities. The test results show that most damages of specimens occur at the location of horizontal steel plate of the lower column, and appear to be cracking of steel plate in heat-affected zones at the weld edges and tearing of steel plate due to the propagation of the cracks. The location arrangement of welds shall be one of the major factors influencing the failure patterns of the specimens. The enhancement effect of installing steel angles or steel tube in the corner cavities shall be the best, the next is that of increasing the thickness of steel plate, while the worst is that of adding multiple cavities. The degradations of bearing capacity of all the specimens are not remarkable. The deformation and energy dissipation ability of the upper column is better than that of lower column. The average value of yield drift ratio of all the specimens is 1/101, the drift ratio corresponding to the peak load is about 1/42, and the maximum elasto-plastic drift ratio is about 1/29, indicating that the columns proposed in this work can be used in the design of mega frame structures of super high-rise buildings.
