Research On The Mechanical Behaviors Of Concrete-filled Double Skin Steel Tubular Column

Concrete-filled double skin steel tubular(CFDST) is a composite structureformed by pouring the concrete between inner and outer concentric steel tubes.Theinner and outer steel tubes replace the steel and have the restraint effect on thesandwiched core concrete. Compared with the traditional concrete-filled steelcomponents, the CFDST components haves the advantage of lighter weight, strongerbending stiffness, better seismic performance and reasonable fire resistance. Although,the research of CFDST mechanical property is not uncommon in the domestic andoverseas at present. While these research mainly concentrated in experimentalinvestigation and theoretical analysis of axial compression of single column, bias ofsingle column, and mechanical property of beam column. Still, there are a lot ofquestions are not well-thought. At the same time, the researches on long columnmechanical property of CFDST and practical engineering application are very rare. Inorder to make this structure be widely applied in practical engineering, we need moresystematic and further research. Given this situation, by virtue of finite elementmethod, this thesis analyses mechanical property of CFDST column carryinghorizontal load under the effect of axial compression and framework for static anddynamic characteristics of CFDST column, under the premise of column length,concrete and steel tube area remains in the same, and hollow section ratio isconsidered as a key parameter. The thesis is of significant importance to furtherapplication in practical engineering.The main contents of this thesis are as follows:(1) The axial compression and the force mechanism of CFDST column whichcarrying horizontal load under the effect of axial compression was analyzed.(2) Under the premise of concrete and steel tube area remains in the same, andhollow section ratio is considered as a key parameter, the mechanical property of fiveCFDST columns was analyzed by virtue of the finite element software ABAQUS.Besides, the influence of the change of hollow ratio on F-D curves, ductility property,and ultimate bearing capacity was analyzed.(3) Taking hollow section ratio and axial compression ratio as the mainparameters the mechanical property of eleven CFDST columns which carryinghorizontal load under the effect of axial compression was analyzed by virtue of thefinite element method. In addition, the mechanical behavior of different hollow section rate columns under the high and low axial compression ratios withstandinghorizontal loads, and the mechanical behavior of the same columns under differentaxial compression ratio withstanding horizontal loads was researched.(4) The static lateral and seismic response of framework of CFDST column wasanalyzed. Statical analysis takes story height and hollow section ratio as the mainparameters, and applies wind load to the beam-column joints. The influences ofdifferent layer heights and different hollow section ratios on the maximum inter-storydisplacement and the maximum inter-story displacement angle of the frame structureswere researched. The time-history response analysis method was used by dynamicseismic response analysis, two kinds of different seismic waves which caused bymodifications on peak number of the frequent earthquake and rare earthquake wereinput, and the dynamic properties of the frame structures with different hollow sectionrate columns under different seismic waves were researched.(5) On the basis of summarizing the results from all analysis, this paper g avesuggestions on how to choose hollow section ratio of CFDST column and how tocontrol the axial compression ratio in practical engineering design.