Study On Mechanical Properties Of High Strength Concrete With High - Strength Spiral Stirrups

Along with the development of science and technology,people are far more curious about the unknown;the people’s congnition of beauty has changed a lot in recent decades;more expectations of the functional demonds and the fabulous appearances of constructures.Therefore, more and more domestic and foreign reseachers have paid more attention to the ultra-high-strength reinforced concrete.In comparison with the common concrete,the ultra-high-strength reinforced concrete shows many advantages,such as smaller cross section dimension,lighter weight,which can reduce the presure of the foundation.The ultra-high-strength reinforced concrete has good properties of density,frost-resistance,impermeability and corrosion-resistance,which makes the comprehensive technical and economic profits much significant.However,the fatal drawback of brittleness makes the ultra-high strength concrete difficult to apply to costructures widely.So the most important problem is how to change the ductility of the ultra-high strength concrete.The purperse of the paper is to establish a model of the ultra-high strength reinforced concrete column comfined by high-strength spiral stirrups,which is the base of the designing of the ultra-high strength reinforced concrete constructures.It is very significant for the costruction of skyscrapers and long-span constructures.Based on the summary of the results of domestic and foreign reseachers,the autor of the paper did the axial compression experiment with 19 ultra-high strength reinforced concrete columns comfined by high-strength spiral stirrups,and has analyse the mechincal behaviour of the ultra-high strength reinforced concrete columns comfined by high-strength spiral stirrups.The main factors include the space of stirrup,the strength of concrete,the scale of dimension. The finding shows that the smller space of stirrup and higher strength of concrete,the higher of the ultimate bearing compacity and better ductility,which agrees with most of the similar reseaches.And the result of this expriement also shows that the ductility and ultimate bearing compacity can be impoved by configurate proper quantity of spiralstirrups.Acording to domestic and foreign reseachers’ achivements of the relation of stress-strain of comfined cocrete and the anlysis of this experiement,the author proposals a new constitutive model of comfined concrete.The results of calculation agree with the results of experiement.The model can be used to analyse the ultra-high strength reinforced concrete column comfined by high-strength spiral stirrups.