Stability Analysis Of Introversive Type Arch Bridge

Arch Bridge is an ancient form of bridge, with a long history, With the development of science and technology, the modern arch bridge is turning toward the large-span and complex system direction to develop, so it is,the main compression member the stability problem is becoming more and more serious and has become the main factors that restrict its development. There are not only pressure on the arch rib of introversive type arch bridge but also bending moment, shear and torque, the force form is so complex that the stable problem must be considered in progress of construction and operation.There are two main types of stability problems, The first kind of stability is problems of eigenvalue, it has important guiding significance for the actual works. But in practice arch bridge stability problems are second kinds of instability problem,due to the structure of the initial defect. So the double nonlinear effect should be considered when analysising the stability of arch bridge.This paper takes Baiguan Bridge which located in the Hunhe Rive at Shenyang city as the engineering background, various structural parameters that influent the stability of this kind of bridge was analysised, and the law the change of the structure parameters influence on arch bridge stability has been mastered by the first kind of stability analysis. At the end of this paper the stability of this bridge at the disadvantageous stage in construction was analysised.The calculation results show that, there is lots of safety margin, and the weakest position in stability of this bridge is the arch rib â…¢ and â…£, The types of instability of arch rib â…¢ are mainly plane bucking, due to the exist of brace, the stability coefficient under load condition one is18.07. The types of instability of arch rib â…£ are mainly out of plane bucking, due to there is no brace on it, the stability coefficient under load condition one is18.44. The geometric nonlinear has great impact on stability analysis in bridge of complex system. Through the calculation analysis, it was known that, the stability coefficient of arch bridge is inversely proportional to boom space which is along the bridge, and is proportional to the internal angle of arch rib and non-directional force, in which the effect of non-directional force is obvious. The stability decreased when considered the geometric nonlinear. In this paper the stability of the most disadvantageous stage in construction was analysised, the results show that the stability of the construction process meets the safety standards.