Experimental Study On Eccentric Compression Of GFRP Tube Reinforced Recycled Concrete Short Columns

In recent years,relying on the three carriages of investment,export and consumption,China has built infrastructure on a large scale across the country to accelerate urbanization and promote the development of China’s economic construction.Due to urban planning and development,a large number of old buildings have been demolished,resulting in a large amount of construction waste being randomly buried and piled up,which has greatly affected the development of the ecological environment.The above problems need to be solved urgently.At present,FRP research is hot,many scholars combined with FRP itself has strong tensile strength,strong corrosion resistance,high temperature resistance and so on.A lot of research has been done on FRP constrained ordinary concrete composite columns,and it is found that FRP can enhance the bearing capacity and ductility of FRP constrained concrete columns.Compared with FRP constrained recycled concrete composite column,there are few studies.This paper mainly analyzes the experimental phenomenon and experimental data to study the mechanical properties of GFRP pipe reinforced recycled concrete short column under eccentric action.A total of 29 composite columns were studied in this test,of which 5 columns were studied under axial compression and the remaining 24 columns were studied under eccentric compression.Based on the test results,the failure mode of GFRP tube reinforced recycled concrete short column under axial and eccentric compression is analyzed.The effects of the replacement rate of recycled coarse aggregate,the strength of recycled concrete,the winding Angle of GFRP tube fibers,the ratio of longitudinal reinforcement and the eccentricity on the load-displacement curve,deflection curve and stress-strain curve of the composite column under the action of bias pressure are analyzed.At the same time,it is verified that the plane section assumption and the deflection curve are close to the sinusoidal half wave curve.Two stress-strain models of constrained recycled concrete were selected for analysis and solution,and the fitting degree of the two models was compared.The model with better fitting degree was substituted into the simplified calculation formula for correction and comparison,which proved that the simplified calculation formula could be applied to simplify the calculation of the bearing capacity of recycled concrete composite column under bias pressure.