Research Of The Influencing Factors On Constrained Concrete Flexural Member Filled With Steel Tube

The concrete will produces instantaneous elastic deformation under loading on the concrete member. Even if the loading does not increases, the concrete will still produces creep deformation. Creep deformation can redistribute the internal force of cement member and structure. Specifically, it has some influence as follows:Creep deformation redistributes the internal force of the concrete member filled steel tube. Creep deformation makes the prestressed concrete produce prestress loss. Creep deformation makes the statically indeterminate structure produce secondary internal force. Creep deformation makes the force of compression member eccentric. Creep deformation makes the deflection of the cement member increase. So it is necessary to research the features and influence factors of the concrete filled steel tube.This paper introduces the mechanic property of the concrete filled steel tube and the working mechanism of its creep. The creep of the concrete flexural member is calculated on the base of concrete creep prediction model and the characteristic of the concrete filled steel tube. Then the creep curve of different influence factors is drawn. The degree of influences of every influence factors on concrete filled steel tube flexural member is analyzed. The development tendency of the creep curve is discussed.Based on the comparison of the creep curves of the concrete filled steel tube under different conditions, the conclusions are educed as follows:The degree of influences of every factor on the creep of concrete filled steel tube flexural member is different. The factors are classified in order of the degree as follows:member size, steel ratio, bending moment, loading age, relative humidity, concrete strength grade, maintenance method and concrete added fly ash. As the loading time prolonging, some creep curves of every influence factor assume convergence tendency. These factors include as follows:member size, loading age, relative humidity, concrete added fly ash and maintenance method. Some creep curves assume divergence tendency and the influence factors include steel ratio and concrete strength grade.This paper researches the creep behavior of concrete flexural member with steel tube and it can provide theory support for large scale application of the concrete flexural member with steel tube.