Piers Stability Analysis Of Jing He Continuous Rigid Frame Bridge

The continuous rigid frame bridge with high piers is built extensively due to its convenience construction as well as economy. Taking the Jinghe Bridge on the Fengxiang road to Changqing bridge section of Xichangfen Freeway in GanSu Province as the background engineering, the stability of structure is studied in this thesis. The conclusion is summarized as follows:(1) This thesis introduces the research result about inland and abroad the stability of bridge in history and current situation. The first and the second kind stability theories are described in detail. The nonlinear analysis methods and formulations of the bridge structure are discussed. Based on the literatures spatial stiffness matrix for a space element is formed by using the U.L Formulation in which the geometrically non-linearity of the bridge due to large displacement by the altering axis method.(2) Adopting the energy method and Finite element method, first-order linear elastic stability in representative construction stages of the Jinghe Bridge are analyzed, which include the highest pier stage, the maxium cantilever stage, so that The first-order Buckling mode and Buckling coefficient were available. The results showed that piers meet the stability requirements. Furthermore, this thesis compared the Buckling coefficients of pies from energy method and that of Finite element method, which showed stablility safety coefficient based on the energy method is larger than that of the Finite Element Method.(3) By using the software MIDAS-FEA, finite element model of piers of Jinghe bridges pier were built. When the Jinghe Bridge is in the maxium Cantilever stage, the relationship between defect in pier, initial eccentricity, tie beam of pier and geometrical nonlinearity stability of the piers are analyzed. The related Buckling coefficient is acquired and compared with that of the elastic analysis. The results demonstrate that there is little difference compared with the elastic analyis when considering geometrical nonlinearity only. In adddition, increasing too many of the numbers of tie beams is not necessary to the stability of the structure.