Research On The Applied Calculation Method For The Special-Shaped Steel Column Subject To Axial Compression And Biaxial Bending

In the steel structure design of residence,the steel frame structure and frame-core tube structure built by hot rolled H-shaped steel are the mainly structure systems.The section size of the H-shaped steel is about200mm×200mm～400mm×400mm,so that the column widen than the wall in the room.This situation influences the indoor space to be used and becomes a problem.The same problem also exists in the reinforced concrete frame structure.In order to solve this problem , researchers studied out some special-shaped reinforced concrete columns.In the similar way,the special-shaped steel column are proposed in civil constructions.For example,the middle column can use crisscross-section,the side column can use T-section,and the corner column can use L-section.And those three kinds of special-shaped steel columns can be make up of H-shaped steel and T-shaped steel.The design formulas about the crisscross-section and the T-section steel column can be found in China current specification for design of steel structures.But the design formula about the L-section steel column still doesn't exist whether in current specification or in some other references.Therefore,the research on the load bearing capacity of the L-section steel column is significant.L-section steel column belongs to abnormity-section steel column in which cross-section doesn't show symmetry axis.Based on the previous studies,the study begins with the general equation of the combined flexural-torsional buckling theory of the abnormity-section steel column.Further more,according to the engineering design method,the general equation is predigested and analyzed.In the end,the engineering design formula is obtained.Firstly,by ignoring the influence of asymmetry terms in the general equation,an equation of flexural-torsional buckling about the two symmetrical steel component can be obtained.In Cartesian coordinates which axes are P Pω,M x M crx0,M y M cry0 this equation is analyzed,and an simplified equation can be obtain.After that substitute the asymmetry terms into the simplified equation,an theory simplified equation can be obtained.Secondly,the influence of initial imperfection,non-uniform distributing load and different constraint condition are import in the simplified equations in terms of specific parameters.And then according to the beam-column theories and superposition method,the engineering design formula can be deduced.Finally,this article also presents several experimental results of the L-section steel column subjected to axial compression and biaxial bending.A numerical simulation by means of finite element package ANSYS is fulfilled and compared with the experimental results.Good agreement is found.Those results prove that the engineering design formula is reasonable and safety.