Abstract: Spatial analysis of special shape column frames and special shape column frames with inclined supports is carried out in this paper using finite element software, Ansys and SAP. The non-linear analysis of a simply spatial frame shows that the torsion stiffness and strength are improved obviously after inclined supports are added. The ductility of the frame is improved, too. Comparing to that of rectangle column frames, the torsion ability of special shape column frames is much lower under seismic load. However, the inclined supports can improve it effectively. Furthermore, advises are given that when the stiffness center and mass center are not coincident in a special shape column frame, inclined supports should be used to improve the torsion ability of the frame.
Key words: Special shape column, Torsion, Spatial analysis