Research On Displacement Of Piers Of Concrete-filled Steel Tubular Tied Rigid Frame Through Arch Bridge On Construction Stages

The Nanpu rainbow bridge in Ezhou city of Hubei province is a concrete-filled steel tubular (CFST) tied rigid frame through arch bridge with a net span of 120m. Concrete-filled steel tubular arch bridge is a new style of bridge that rose about ten years ago. It uses the feature of high compressive strength of concrete-filled steel tube to depress deadweight, and construct without brackets. Concrete- filled steel tubular (CFST) tied rigid frame through arch bridge uses tie bar to balance the horizontal thrust. So it is an arch bridge without thrust. But the stiffness of tie bar is lower, the increment of thrust will be borne by pier. So pier will still exist horizontal displacement, and it will bring additional internal force in the arch ring. So the research about the displacement of pier will have important referenced value in engineering.First this thesis analyses the reasons of the displacement of piers, and based on Winkler foundation model, piles are regard as erect beams on elastic foundation and surrounding soil of piles are regard as discrete linear spring, then obtain elastic differential equation of pile that bear horizontal load. Power-series solution is obtained by solving the equation. On the basis of the solution, considering holistic distortion and compatible relation of internal force, the complete solution is obtained about pile through several soil layers. Associated with the practical engineering of the Nanpu rainbow bridge in Ezhou city of Hubei province, using this solution to calculate the displacement of pier under horizontal load of various cases.Using software of the finite element to set up the spatial model of bridge, and then simulate the distortion of pier under spatial forces. A comparison of computed result of the finite element with theoretical result shows good agreement. Associated with experimental result, the conclusion is obtained that "m" method based on Winkler foundation model calculating the displacement ofpiles bearing horizontal load can satisfy the require of engineering on the condition of small displacement.Some problems about this research worth to be studied afterward are put up in the end of the thesis.