Experimental Study On The Buckling Performance Of Reinforced High-strength Concrete Columns Confined With GFRP Tube

With the progress of society and the development of the economy,ordinary concrete is no longer able to meet the requirements of many high-rise and super-high-rise buildings for loadbearing components’ carrying capacity.Therefore,the application of high-strength concrete has become increasingly widespread.However,high-strength concrete has the characteristics of high brittleness and poor ductility.To further enhance the strength of concrete and improve the deformation performance of high-strength concrete components,the common method is to use steel tube-confined concrete composite structures.However,the poor fire resistance,poor corrosion resistance,and high maintenance costs of steel tubes have led to situations where this composite structure is not applicable in many cases.Therefore,a new type of composite structure,FRP-confined concrete,has emerged.Domestic and foreign scholars have also conducted a lot of research on FRP-confined concrete.However,when applying FRP confinement to high-strength concrete,the increase in material strength will inevitably lead to a decrease in the column section size and an increase in the slenderness ratio,making the component more prone to instability failure.Therefore,this article uses a combined method of experimental research and theoretical derivation to explore the buckling performance of GFRPconfined high-strength concrete columns under axial compression:1.Twelve axial compression tests were designed and conducted using GFRP tube-confined high-strength concrete with parameters such as GFRP tube thickness,section shape,section size,and column height to investigate the influence and regularity of key parameters on the mechanical stability of GFRP-confined high-strength concrete columns.2.The section bearing capacity calculation method of GFRP-confined concrete and the dimensionless slenderness ratio were modified based on the experimental results.The buckling curve and its expression of GFRP-confined high-strength concrete columns within the range of dimensionless slenderness ratio of 0-1 were fitted.3.A new method for measuring and calculating the initial bending of composite structure columns was proposed based on the characteristics of the test pieces.By calculating the height of initial bending moment,the Perry-Robertson formula in steel structure stability theory was used to propose a calculation method for the stable bearing capacity of slender(dimensionless slenderness ratio above 0.2)GFRP-confined high-strength reinforced concrete columns.The validity and availability of this method were verified based on the experimental results.However,further research is needed to accurately calculate the stable bearing capacity.