Static Behavior Research On CFRP-Steel/FRP Composite Tube Confined Steel High Strength Concrete Short Columns Under Axial Compressive Load

Carbon fiber reinforced polymer(CFRP)has many advantages such as high strength-to-weight ratio and good corrosion resistance and so on.Structure columns should meet the requirement of bearing capacity and resistance to corrosion in high-rise buildings and periodic water environment.In order to adapt the developing trend of structure columns,an innovative composite structure column,named as CFRP-steel composite tube confined steel high strength concrete column,is proposed based on the concepts of FRP confined concrete column,steel tube confined concrete column and FRP confined steel tube concrete column.This new type of composite column confines steel tube confined concrete column with CFRP wraps to provide additional transverse confinement.To enhance the compressive strength and shear resistance capacity of core concrete column,C80 concrete has been used and steel has been put into core concrete in the process design of the specimens.Based on the monotonic axial compressive performance research of CFRP-steel composite tube confined steel high strength concrete short column,static behavior of FRP composite tube confined steel high strength concrete short column has been researched heuristically under axial compressive load and comparative analysis has been done between them.The specific contents of this paper are as follows:(1)A series of experimental studies were careied out to investigate the failure process and the failure mode of CFRP-steel composite tube confined steel high strength concrete stub columns.In this paper,the destruction of the whole process in detail were described,the failure process and the failure mode wre analyzed theoretically,at last the failure mechanism were elaborated.(2)The load-strain curves of CFRP-steel composite tube confined steel high strength concrete stub columns and other different types specimens were analyzed specifically.The axial behavior of specimens with different factors including the CFRP confinement factor,section type of columns and mechanical performance of steel tubular were analyzed.(3)FRP composite tube confined steel high strength concrete stub columns were tested under axial compressive load to investigatethe the failure process,the failure mode and the mechanism.The load-strain cruves of specimens were analyzed and experimental conclusions were drawn.(4)The effects of the steel tube confinement factor,steel tube/GFRP tube(internal confinement material),internal steel and CFRP wraps layer on the compressive property of FRP composite tube confined steel high strength concrete stub columns were investigated.The comparative analysis were carried out about the cooperative work property between CFRP wraps and steel tube /GFRP tube.(5)By combining the experimental research and the related theories of steel tube confined concrete column,CFRP confined concrete column and overseas study,the formula for calculating the axial compressive bearing capacity of CFRP-steel compostite tube confined steel high strength concrete stub columns and FRP composite tube confined steel high strength concrete stub columns was proposed.