Research On The Stability And Ultimate Capacity Of Long-span Steel Arch Bridge

With the increase of the span of the arch bridge, the stability problem become more and more evidence and become one of the most important control factor of arch bridge design. This paper bases on the first design plan of Dong-Sha bridge located in PanYu,Guan-Zhou, through processing stability analysis ,and discusses all kinds of factors affecting the stability of long—span steel arch bridge and provides profitable suggestion for design of the same kind of bridge.Stability problem generally is divided into two sorts. The first type comes down to evaluate eigenvalue problem, which is easy to be calculated. Due to the effect of the material nonlinear, geometry nonlinear and original bug, the second kind stability is ultimate load carrying capacity problem, which is more reasonable comparing to the true result. The existing theory is my paper's guidance, considering both of the eigenvalue stability and ultimate load carrying capacity, I use finite element method, anglicizing the material nonlinear influence and geometry nonlinear and original bug upon stability factor and stability of arch bridge, arch rib obliquity's influence upon stability and ultimate load carrying capacity of arch bridge, transverse wind load influence upon ultimate load carrying capacity of arch bridge.The result of the calculation indicates that there are a rather sectional rigidities of arch rib , cross beam and radio of width-long ,the dead load of arch will much bigger than the vehicle load and wind load in operation, and the in-plane stability will larger than the out-plane stability and the in-plane stability is the main factor controlling of design.In the given geometry original bug, there is a few difference between the result of eigenvalue buckling analysis and the result of geometry nonlinear buckling analysis. Due to the material nonlinear influence, the result of nonlinear buckling analysis is far lower than the result of eigenvalue buckling analysis method due to the influence ofmaterial nonlinear, eigenvalue buckling analysis may induce non-conservative result.With the rake angle from one degree to eleven degree, the stability factor of eigenvalue buckling analysis is increasing, it will reduce when the rake angle still become bigger in this step.When the in-plane stability of such arch is in control of the bridge design, Transverse wind load has a little influence on the stability factor and ultimate load carrying capacity. The resistivity of wind load is not the main factor of the arch design. So it is a just right choose to design a similar arch bridge in the place that there is a big wind load.It only research all this factors about the stability of arch bridge in singer factor but not thinking about all factors in the same time. When coming to the unfavorable condition in the construction of an arch bridge, it is important to check the stability carefully. In facts, the wind load is not static, but dynamic. And the wind load is nonlinear. It regard the temperature load in the way of ascending temperature of the whole bridge regardless the local temperature difference. And it does not think about the welding remain stress. All these factors have great influence on the stability factor and the Ultimate load carrying capacity, which are worth further study.