Research On Axial Compression Performance Of GFRP Tube Filled With Steel Reinforced Recycled Concrete Composite Columns

GFRP(Glass Fiber Reinforced Polymer)has the advantages of light weight,high strength and corrosion resistance.And the application of recycled concrete has good economic and environmental benefits.Therefore,GFRP tube filled with steel reinforced recycled concrete composite columns were proposed to effectively utilize the environmentally-friendly recycled.concrete,give full play to the advantages of the superb corrosion resistance of GFRP and the good ductility of steel.In order to better understand the axial compression performance of GFRP tube filled with steel reinforced recycled concrete composite columns,GFRP tube filled with recycled concrete composite columns were proposed,and the two composite columns were analyzed comparatively.The specific contents are as follows:13 GFRP tube filled with recycled concrete composite columns were designed and manufactured.The failure process and failure modes of GF RP tube filled with recycled concrete composite columns were analyzed in detail.Based on test data,the effects of recycled coarse aggregate replacement rate,slenderness ratio,recycled concrete strength grade in composite columns’ axial compression performance were studied in detail b y the analysis of load-disp lace ment curve of the composite columns,load-strain curve of the GFRP tubes,transverse deformation coefficient of the GFRP tubes and the axial bearing capacity.11 GFRP tube filled with steel reinforced recycled concrete composite columns were designed and manufactured.Compared with GF RP tube filled with recycled concrete co mposite columns,the failure process and failure modes of GFRP tube filled with steel reinforced recycled concrete composite columns were analyzed in detail.In addition to recycled coarse aggregate replacement rate,slenderness ratio,recycled concrete strength grade,the axial compression performance of GFRP tube filled with steel reinforced recycled concrete composite columns which was affected by the ratio of profiled steel was also considered.The difference in axial compression performance of the two composite columns was studied in detail by the analysis of stress-strain curve of the two composite columns,stress-strain curve of the GFRP tubes and the axial bearing capacity.The test results showed that the axial compression performance of GFRP tube filled with steel reinforced recycled concrete composite columns was good.The profiled steel improved the ductility and axial bearing capacity of the composite columns significantly.Compared with GFRP tube filled with recycled concrete composite columns,the axial bearing capacity of GFRP tube filled with steel reinforced recycled concrete composite columns was increased by 10.6%on average.Based on the twin shear unified strength theory,the calculation method of the axial bearing capacity of the two composite columns was deduced by the analysis of stress state of recycled concrete,GFRP tube and profiled steel.For engineering applications of the composite columns,the theoretical calculation value was compared with the experimental value.