Study On The Effect Of Initial Stress On The Stability Of CFST Arch Bridge

In recent years,Steel Reinforced Concrete(SRC concrete)has been more and more used in the construction of arch bridge.The general order of construction using SRC concrete is that steel assemble the arch— Mico expansive concrete poured— Stiff skeleton arch is as support,which poured into outsourcing concrete by layered section method—Arch building constructed.When the skeleton method being used in the construction,before the core concrete and the steel tube has not formed the joint structure,Steel will produce the initial stress and initial strain under the action of self-weight and wet weight of concrete,and initial stress will affect the stability and bearing capacity of concrete-filled steel tubular arch bridge.Paper relies on the boli channel bridge which is the 170 m span deck type CFST arch bridge as the engineering background,a,with the help of finite element software ANSYS for the linear and nonlinear stability analysis of the bridge,at the same time,the influence of various parameters on the stability is calculated and analyzed,finally,the finite element software Midas/Civil is used to calculate the bearing capacity of the bridge considering the influence of initial stress,and the main contents are as follows:1?The paper reviews the development of steel tube concrete structure,and expounds the application of steel tube concrete in bridge construction,and the research status of the initial stress tube and the stability of concrete-filled steel tubular arch bridge is discussed in this paper,the definition and theoretical calculation method of initial stress are introduced as well,in addition,this paper introduces the concept and classification of arch bridge stability,and the finite element method stability analysis of arch bridge are discussed and deducted.2 ? Relying on the boli bridge as engineering background,the space model is established by using the finite element software ANSYS,in which the constitutive model of concrete in steel KINH and MISO materials are adopted to perform the linear and nonlinear stability analysis of the bridge.The model analysis the material nonlinearity of considering the hoop and do not consider the hoop and the double nonlinearity of considering the hoop and do not consider the hoop and geometric nonlinear analysis considering geometric defects are taken into consideration in nonlinear stability analysis.After analysis and comparison,the geometric nonlinear of considering hoop action is selected as the computational method of analysis of the influence of different parameters of the stiff skeleton arch bridge stability under different initial stress degree.3?The paper studies the influence of the concrete-filled steel tubular arch bridge stability coefficient under the span(130m,170 m,210m,250m),steel ratio,steel type,core concrete grade,different perfusion sequence,the initial geometric imperfection,and builds more than simplified formula 200 m span and span of less than 200 m,which is not less than 0.9 as the boundary,suggested the optimum range is less than 0.6.4?With the help of finite element software Midas Civil and fitting function,which is included in the reduction of the initial stress,the bearing capacity of the boli bridge is checked,which can meet the requirements of the specification.