Continuous Rigid Frame Bridge To Change The Stability Analysis Of The Cross-section Of High Pier

In the period of "the 11th Five-year Plan", the construction of highway of our country is being extended and developing constantly to the mountain area, design style of bridge piers changes from short-thick style to long-thin style, therefore stability issue of high piers exposes to be paid attention to. This paper introduces the state of development and structure characteristic of continuous rigid frame bridge; based on the project background of Yin Jia-xi Bridge, the stability of high piers with variable sections and elastic bearings is analyzed. The following main research results are obtained:1. Based on the Rayleigh-Ritz energy method and the assumption of unified shape function, the paper deduces the formula for critical load in the erection and construction stage of high piers, and calculates the critical load of the piers of Yin Jia-xi Bridge.2. The critical loads, including linear and nonlinear values, of No.4 and No.5 piers in every stage are calculated by use of common structural finite element program, and the linear results are compared with those results from the energy method and approximate method of rigid frame bridge, with the maximum difference being 10.5 percent. The stability factors of No.4 and No.5 piers in the erection and work stages are calculated by using the finite element's results, the conclusion that the nonlinear stability factor of No.5 pier in the erection stage is the minimum value with 6 is obtained.3. At last stability parameter analysis of high piers is carried out according to the deduced formula in the paper; the influences, including material of pier shaft, the diameter of piers, the length of piers and the bearing stiffness at the bottom of piers, over the longitudinal stability are discussed.