Study On Construction Stability Control Of Wide Box Single Cable Plane Concrete Cable-stayed Bridge

The single cable plane cable-stayed bridge is widely used and has distinct structural features.The anti torsion effect of the cable on the main girder is limited,especially in the construction stage.In order to study the torsional effect of the eccentric load and the stability under the static wind load in the construction stage of the single cable plane cable-stayed bridge,this paper uses the finite element simulation method to analyze this kind of bridge based on the actual bridge engineering The stability of the typical construction stage,and put forward the control index.The spatial refined finite element model is established.Four typical cantilever construction states are selected in the whole construction stage,and three eccentric load grades are set up.The section displacement and stress in each stage are analyzed in detail,and the torsional performance of the bridge in the cantilever construction process is evaluated.The influence of deflection movement on the torsional displacement of the structure is studied,and the index of controlling deflection torsional effect in the construction stage is put forward.In this paper,the basic theory of computational fluid dynamics(CFD)is introduced in detail,and the appropriate model analysis method is selected to study the static wind load three component coefficient of the main girder section of the single cable plane cable-stayed bridge.Through the visualization of the cloud chart of wind field,the reasons for the variation of each coefficient are analyzed.Considering the accuracy of the calculation of the static wind load in the following static wind stability,the variation of the three-component force coefficient under the influence of different wind field speed and different section parameters is studied,and the variation law of the three-component force coefficient under the influence of the standard wind field speed and the section parameters of the main beam is obtained.The theory of three-dimensional static wind of bridge is introduced.Accordingto the form of static wind instability,the value of three-component force coefficient of section in each construction stage is selected reasonably,mainly including resistance coefficient and lifting moment coefficient.By introducing the effective wind angle of attack,the calculation of static wind instability is considered as a non-linear problem,and the calculation flow method is put forward.Two critical wind speeds of static wind instability in the construction stage with torsional instability risk are obtained.Using the evaluation method of wind resistance,the wind resistance performance of the bridge in the construction stage is evaluated.The results show that the bridge can resist the extreme wind speed once in a hundred years,and the wind resistance performance is good.