Research On Optimal Setting Of Auxiliary Pier On Cable–Stayed Bridges With Unequal Height Towers

As an important part of the cable-stayed bridge with unequal height towers, Under normal circumstances, when the height of the side span is little or not affect navigation, choose increasing auxiliary piers to improve the stiffness of the cable-stayed bridge. Currently domestic and foreign research on cable-stayed bridge with low tower, single tower and equal height towers are more, But research on cable-stayed bridge with unequal height towers are is still small.In order to study the influence of auxiliary pier’s number and position to the force characteristics of cable-stayed bridge with unequal height towers. This article established the finite element model of using stage and construction phases under three scenarios with one, two and no auxiliary piers at the side span and the finite element models with a single auxiliary pier in different locations by using finite element analysis software MIDAS Civil 2013, analyzed the influence of auxiliary pier to the cable-stayed bridge with unequal height towers.Research indicates: compare with no auxiliary pier model, the single auxiliary pier model can slightly increase the cable tension of dead load, greatly reduce the bending moment and displacement under dead load and live load and improve the overall stiffness of the structure. For example, a pier auxiliary model can significantly reduce moments(74%) and displacement(77%) at side span of the higher tower, reduce moments at the bottom(35%) and displacement at the top of the higher tower(27%) in moving loads, However, the difference between an auxiliary pier and two auxiliary pier is little, which instructions continuing to increase the number of auxiliary pier to improve the structure stress performance is limited; the reasonable location of single auxiliary pier is about 0.4L from side pier; compare with no auxiliary pier model, the single auxiliary pier model can make fundamental frequency increased 15.85%, but compare with one auxiliary pier model, the two auxiliary pier model only can make fundamental frequency increased 1.12%, which instructions continuing to increase the number of auxiliary pier to improve the structural rigidity is limited.