Bearing Capacity And High-rise Engineering Application Of Special-shaped Column Composed Of Concrete-filled Square Steel Tube

Special-shaped column composed of concrete-filled square steel tube(SCFST column)is a new structure column,formed by assembling mono-column.SCFST column has been used in many practical engineering.Paper wills analysis its ability of fire resistance,bearing capacity after fire,uniaxis eccentric compression behavior and application in framen-shear wall system.Firstly,the current situation of special-shaped column was introduced to offer theoretical foundation for the next research.Under the foundation of picking reasonable material thermal performance,the three-hour fire resistance test of SCFST column was analysised by finite element simulation.The result of the finite element simulation agreed with the result of the test.Then,the thickness of ALC palte,the steel ratio of the section,the thermal conductivity of the ALC plate and fire-resistant time were studied to improve the fire-asisrance ability of SCFST coulumn.In order to analyze its mechanical properties after fire,experiment of axial compression bearing capacity for SCFST column was done.The ultimate bearing capacity of SCFST column was not influented by fire.Finally,the crush of concrete and buckle-creak of steel tubes at the fixed end leaded to the loss of bearing capacity.The ultimate bearing capacities and failure mode getting form finite element analysis and superposition theory were basically identical to the results of test.The initial stiffness of SCFST column decreased,the ultimate beating capacity decreased and yield distance increased with the increase of the eccentric distance.The ultimate bearing capacity and initial stiffness of the reverse direction was bigger than the forward direction.Besides,the destruction phonemenon of reverse direction was flexural-torsional buckling.SCFST column frame-brace system has been applicated in the Fukang project residential building successfully.This paper found that this system was sensitive to the wind load.The finite element analysis software was used to analyze the structure performance under wind load,frequent earthquake and rare earthquake.After static elastoplastic analysis,we found that the building had reasonable damage mechanism.