Research On Mechanical Performance Of GERP Tube Confined Encased Steel Recycled Concrete Long Columns Under Eccentric Loading

Recycled concrete is a kind of green material,but it has some disadvantages such as,low strength,high porosity.In order to improve the performance of recycled concrete effectively,recycled concrete,steel and GFRP tube can be combined to form a new type of composite component-GFRP tube confined encased steel recycled concrete columns,which can not only use waste concrete effectively,but also fully take advantage of light weight,high strength,corrosion resistance and effectively confining recycled concrete of GFRP tube and high strength,good ductility of steel.Based on the previous research results of our research group and according to the stress state of the vertical members in the practical projects,this paper has carried out experimental research and theoretical analysis on the mechanical performance of GFRP tube confined encased steel recycled concrete long columns under eccentric loading.The main research contents are as follow:1.Test the material properties of the natural aggregates,recycled aggregates,GFRP tube and steel which used in GFRP tube confined encased steel recycled concrete long columns,including: apparent density,water content,water absorption of coarse and fine aggregates,crushing index and Los Angeles wear coefficient of coarse aggregate,compressive strength test of recycled concrete,tensile test of section steel,axial and hydraulic test of GFRP tube;2.With the layers of GFRP tube,recycled coarse aggregate replacement rate,heightdiameter ratio,eccentricity as the main parameters,10 GFRP tube confined encased steel recycled concrete long columns was designed and manufactured to eccentric compression test.3.Based on the test phenomenon of GFRP tube confined encased steel recycled concrete long columns,failure modes of each test components,encased steel and recycled concrete were compared and analyzed.4.According to the comparative analysis of 10 specimens’ test data such as,bearing capacity and deformation,the mechanical properties of GFRP tube confined encased steel recycled concrete long columns under eccentric loading were studied,and investigate the influences of the layers of GFRP tube,recycled coarse aggregate replacement rate,highdiameter ratio and eccentricity on its mechanical properties under eccentric loading.5.Based on the completed GFRP tube confined encased steel recycled concrete short column under axial compression test results,the calculation formula of bearing capacity of is obtained by superposition method;Considering the high-diameter ratio and eccentric distance reduction coefficient,the calculation formula of bearing capacity of GFRP tube confined encased steel recycled concrete long column is established by empirical coefficient method,and the correctness and applicability are verified by comparison with the test results.