Stability Analysis Of Long-span Continuous Rigid-Frame Bridge With Double Limb Thin-walled High Piers

With the rapid development of our country’s transportation enterprise and large-scale construction of highway bridges and other infrastructure, long-span continuous rigid-frame bridge because of it’s unique characteristics and advantages and has been widely used.Such bridges generally adopts the method of cantilever construction, environment construction process is complicated and the less controlled, and gradually to the trend of development of long-span, gently, makes the structure stability problem is particularly prominent, therefore, research the problems of stability of the continuous rigid-frame bridge is become very important. In this thesis, a continuous rigid-frame bridge as the engineering background, the stability of high piers and long-span continuous rigid-frame bridge is analyzed and researched.The mian research work is summarized as follows:(1) Introducing the development of long-span continuous rigid-frame bridge’s structure characteristics and the classification method, expounds the domestic and foreign research present situation and future development trend of continuous rigid-frame bridge,explained the stability of bridge structure theory in detail, and summarizing several common methods to solve the critical load.(2) Based on the finite element program Midas/Civil, using beam elements to establishing the finite element model at different stages of this bridge, analysis the 7# main piers of autologous stability, the largest cantilever construction stage bridge stability and the stability of the whole stage, it is concluded that the stability coefficient and buckling modes of each stage in the different working conditions, summarizing high piers and long-span continuous rigid-frame bridge construction phase stability of linear variation, and proposed some advice for reference.(3) Considering the maximum cantilever construction stage condition is more complex, the security is low, so analysis the geometrical nonlinear stability of ideal condition;initial defect;wind load;initial defect and wind load influence, got the high piers nonlinear stability safety factors, and the effect of wind load;initial defects on the stability of the continuous rigid-frame bridge.The research content of this paper for continuous rigid-frame bridge provides a theoretical guarantee stability, as well as provide some reference and suggestions for the similar bridge stability.