Analysis On Ultimate Bearing Capacity Of Steel Encased-steel Reinforced Concrete Composite Beam And Its Application In Girder Transfer Floor Structure

With the social and economic development,there are many fuctions need for high-risebuildings.One of structure types is transfer floor structure,the lower part is business and theupper part is house building,has been built more and more. Although this structure type issolved many fuctions for high-rise buildings,there are still many difficulties for the design andconstruction of transfer floor structure, especially for girder transfer floor structure.Compositestructures are the best choice for girder transfer floor structure,but traditional compositestructures still have many problems.Therefore,design a new structure form has manyadvantages, not only convenient to the design and construction of girder transfer floorstructure,but also improved the overall performance of structures.Summarize the current research of composite beams and analyze the advantages anddisadvantages of traditional composite beams,in order to propose and explain the concept ofsteel encased-steel reinforced concrete composite beams.Then describes the advantages of thisnew composite beam section.Establishes the theory formula of steel encased-steel reinforcedconcrete composite beam’s ultimate bearing capacity,outlines the selection process of finiteelement software,units selection and modeling process.Use ABAQUS analysis to determinethe several important parameters of high ratio, aspect ratio,etc. The high ratio of steel encased-steel reinforced concrete composite beams in the range of14to18, the best high ratio is15;the aspect ratio in the range of2/3to1, the best value is1,and because the bottom plate shearlag effect, this beams should not be made wide flat beams; in the same steel ratio, add thethickness of the bottom plate can increase the combined beam carrying capacity by7.30%and13.45%, so increasing the thickness of the bottom plate of this beam is better for flexuralstrength than increasing the thickness of the web and flange steel obviously. Then describe thedetailed measures of steel encased-steel reinforced concrete composite beam.Use SAP2000to analyze three transfer beams,such as reinforced concrete transfer beams,steel reinforced concrete transfer beams and steel encased-steel reinforced concrete transferbeams.There are many important factors to affect the design of high-rise buildings,such asdisplacement ratio,the period ratio,axial compression ratio,etc. Compared these factors toanalyze the mechanical properties of the three transfer beams.Then with the aboveanalysises,summarize the advantages of steel encased-steel reinforced concrete transfer beamsin girder transfer floor structure.