Study On Local Structural Design Parameters Of Ground Anchored Concrete Single Oblique Pylon Cable-Stayed Bridge

Single slanted pylon cable-stayed bridge is of novel design and clear mechanical conception,slanted pylon,cable and main beam perfect interpretation of the balance of force beauty.When the main beam is heavy and the tower is light,it is necessary to set up the corresponding backcable support tower.For no side span bridge,it needs a special anchor structure to anchor the back cable,form a ground anchored single-oblique-pylon cable-stayed bridge.At present,the cable-stayed bridge with single slanted pylon is widely used in China,but there is a relatively small number of ground anchored single-oblique-pylon cable-stayed bridges with no side span,so it is necessary to carry out the relevant research work on this type of bridge.In this paper,based on the science and technology project of Guizhou provincial department of transportation,"the key technology research on the construction of the anchored concrete inclined pylon cablestayed bridge of Furong River Bridge"(2016-123-048),starting from the study of local structure,studying on the local structural design parameters of ground anchored single-oblique-pylon cable-stayed bridge by using a combination of theoretical analysis and finite element calculations.The main research contents and related conclusions are as follows:(1)Based on the simplified mechanical model,the influence of four main design parameters on the stress of anchorage zone is analyzed theoretically,the finite element software Midas/FEA is used to simulate the ground anchor box,and the reasonable simulation method of the boundary conditions and the influence of prestress on the stress of the anchorage zone are discussed.At the same time,the influence of the four parameters on the stress of the anchorage zone is analyzed by numerical calculation,which proves that the theoretical analysis has certain applicability.Finally,the sensitivity degree of each parameter is obtained by defining the sensitivity coefficient k,and the theoretical results are consistent with the results obtained by the finite element analysis.(2)The main form of the cable and the plane layout of the asymmetric cross cable are described,according to the "two equilibrium" principle of force and moment,the anchor position of the back cable on the leaning tower is discussed.According to the formula derivation,the relationship between the the ratio of stay-cables spacing of beam and tower and the axial force of the main beam,and the relationship between the inclination of the tower and the axial force of the main beam are obtained,and the influence of the stiffness of the cable(ground anchor cable,main span cable)on the deflection of the main beam and the horizontal displacement of the tower are obtained.The finite element model of the bridge is established by Midas/Civil,and the two parameters(the elastic modulus and area of the cable)related to the stiffness of the cable are analyzed and compared,and discusses the influence of the horizontal spacing of the mainspan cable on the tower.(3)The anchor form and design points of the tower are elaborated,and the Midas/FEA finite element software was used to analyze the cross-anchorage structure of the leaning tower,the stress distribution of the tower under various working conditions is discussed.The effect of transverse prestress of cable tower is analyzed,and puts forward some suggestions for its lateral arrangement.The stress distribution of the stress at the intersection of the upper edge of the M18 anchor block and the anchorage surface is analyzed in detail,and its stress attenuation law is obtained.At the same time,the influence of the outer steel plate on the anchorage zone of the tower is also discussed.