Structural Stability Analysis Of Long Span Cable Stayed Bridge

As the main bridge across the river, cable-stayed bridge wins more and more favor of engineering with its basic design theory and matureconstructiontechnology. With the popularization of high-strength materials and the progress of construction equipment and construction technology, the span record of cable-stayed bridgeis constantly refreshedin recent years.Problems that come witheven more prominent.Because of the mature of special computer software of the bridge, conventional static and dynamic calculation of large cable-stayed bridge has almost no technical obstacles.In order to increase the span of cable-stayed bridge, its main tower becomes higher, and the wall of the beam thinner,so the stability of large span cable-stayed bridge has become very prominent.Although the ratio of instability problems in bridge engineering accident is low, there still have been a few bridge accident caused by instability.So we should pay attention to the stability issues in the design and construction of cable-stayed bridges.The background of this study is Wuhan Yangtze River highway bridge whichis one of the main spans of controlling project across the Yangtze River of Wuhan four link. It is a continuous half-floating system steel cable-stayed bridge whose main span is 760 m,twin towers 5-span, so the stability issue is quite prominent.The stability analysis on this bridge for the bridge construction and operation phases of the quantitative evaluation on structural stability, view the phase margin of stability.This extra large bridge of stability analysis for the bridge structural stability to make quantitative evaluation of the construction and operation stages, to check the stability in different stages of the surplus quantity.Introduces the background of the theory of structural stability theory first class stability theory and stability theory of the second kind.Explains the basis two types of stability, essential difference, and discusses two types of stability theory corresponds to the stability coefficient method and factors affecting the stability of cable-stayed bridges, evaluation standards..By space calculation model of limited element software Midas Civil contains 131 construction stage engineering background according to the construction process of cable-stayed bridge, extract the bare tower state,maximum double cantilever state, edge folded across the state, the largest single cantilever state, folded across the state and state into a bridge of six kinds of typical working condition and analyze stability.First of all, by the buckling mode and buckling analysis solution to the six typical working conditions to this kind of stability factor;Secondly, through the control points in each stage of solving nonlinear analysis module load- displacement curve and the buckling mode, launched by the curve of the corresponding phase instability critical point and the ultimate load, geometric nonlinear stability coefficient is obtained.The last,analyze the result of the two parts of stability,analyze and evaluation the stability of the bridge.