Research On Axial Compression Performance Of Recycled Concrete Filled Circular Steel Tube-profile Steel Composite Columns

With the social development change rapidly, the construction industry has been booming,resulting in the increase of construction waste especially waste concrete.On the one hand,the application of recycled aggregate concrete (RCA) technology can deal with a large number of abandoned concrete, on the other hand, The using of RCA to take place of natural aggregate can reduce the consumption of natural resources and protect the ecological environment,It is in line with the state environmental protection and the strategy of sustainable development. The recycled concrete filled circular steel tube-profile steel (RCFCSTPS) composite columns is proposed in this paper. As a new type of composite columns that have made full use of the advantages of steel- reinforced recycled concrete column and recycled aggregate concrete filled tubular . Steel tube play a good role in constraint the internal regeneration concrete. the profile-steel ? steel tube and RCA three shared load in common.lt improved the bearing capacity and deformation capacity and the consumption of waste concrete, so it has good engineering application value. In this paper, through the test and theoretical methods , the mechanical properties of (RCFCSTPS) composite columns under axial load were researched in detail .The design calculation methods of columns were also put forward in this paper.According to the characteristics of recycled and composite structure, the recycled concrete materials which met strength requirements were designed and prepared. On the above basis, 11 recycled concrete filled circular steel tube-profile steel composite columns were designed and produced in this paper. The design parameters mainly include replacement percentage of recycled coarse aggregate(RCA), diameter to thickness ratio of steel tube, steel reinforced ratio,slenderness ratio. Through the axial compression test research of recycled concrete filled circular steel tube-profile steel composite columns, the failure process and modes of the columns under the axial compression were studied, and the load-displacement curves,load-strain curves of steel tube, load-strain curves of profile-steel, lateral deformation coefficient curves of steel tube were analyzed. On the basis, the impacts of design parameter include replacement percentage of recycled coarse aggregate(RCA), diameter to thickness ratio of steel tube, steel reinforced ratio, slenderness ratio on axial compression performance of recycled concrete filled circular steel tube-profile steel composite columns were studied in detail.kinds of theories include limit analysis, the twin shear unified strength theory and superposition principle,respectively,the ultimate bearing capacity calculation formula which applies to recycled concrete filled circular steel tube-profile steel composite columns is proposed.The formula which build based on the different theory have been compared and analyzed, the Applicable conditions are given, The conclusions can be helpful for the scientific study and engineering application of recycled concrete filled circular steel tube-profile steel composite columns.