Stability Analysis On Thin-Wall High Pier Bridge In Mountainous Region

Chinese road transport volume is increasing, and promote the rapid development of highway construction, high pier and long span continuous rigid-frame bridge was applied and promoted in bridge construction projects, especially in the mountain gully region, high-piers continuous rigid frame was much more applied by a wide range of area. With the constant breakthrough in pier’s height, its stability will still be highlighted. From the construction process of the bridge, we can see that the world has had so many casualties bridge collapse instability and loss caused by the carrying capacity that the stability of high pier is becoming increasingly important. Taking the high road pier continuous rigid frame bridge- Yang Bay Bridge in the background, the construction of the bridge in the stability analyzes, the key elements as the following:(1) Describing two types of stability problems of bridge structure to understand the method for solving the problem of stability; summarizing the evaluation criterion and structural stability.(2) Using the finite element software Midas civil bare pier of the bridge points, the largest cantilever state, a bridge phase stability analysis. By analyzing the three construction phases, we can draw the most unfavorable load cases each phase. In addition, the stable eigenvalues largest cantilever state minimum, this means that the state is the most unfavorable stage; in the most unfavorable load conditions, the three-phase were geometrically nonlinear stability analysis, the buckling mode structure, and through the load-buckling load displacement curve obtained and all conditions of stability safety factor. We can draw that geometric nonlinear factors have an impact on the structural stability and reduce the stability of the structure to some extent; in various stages of construction, the axial force in the pier bottom and the maximum displacement become larger due to the presence of non-linear factors, especially the axial force in the pier bottom and displacement is obvious in the state’s largest cantilever, we can conclude that it is necessary considering the geometric nonlinear.(3) Obtaining the most adverse temperature according to the measured temperature data and the temperature curve based on semi-theoretical simulation and semi-empirical formula, drawing nonlinear temperature stresses simulation equations according the theory and change into linear equations. Analysis of the effect of temperature on the sunshine continuous rigid frame bridge self- stable and cantilever construction process affect the stability and maximum displacement of a bridge under the bridge situation and through calculation and analysis the effect is relatively small, especially the smaller impact on the stability of the longest cantilever bridge in the state. Sunshine influence of temperature on the deformation of the bridge is not obvious.(4) The number and arrangement of the beam position cross between double-limb thin-wall pier set on the high piers have some influence in stability, and more of the beneficial effects, but taking some factors into account such as the cost of construction, it is not better setting more. In addition, the uniform layout beam of high pier favor of the stability; the increases of concrete strength lead to the stability of high pier will also increase, but the magnitude is not increase much, indicating that efficiency of enhancing the stability of high pier initiatives by increasing the strength of the material to is not high; increasing wall thickness can improve the stability of the whole bridge, but at the same time increasing the amount of material, increasing the pier shaft section stiffness increases is not conducive to box girder stress and deformation, it is necessary to control the thickness of choice within a reasonable range.