【作者】 梅建松；

【导师】 蒋沧如； 王小平；

【作者基本信息】 武汉理工大学 ， 结构工程， 2005， 硕士

【摘要】 随着拱桥跨径的增大,稳定性变得越来越突出,成为拱桥设计的重要控制因素之一。本文以广州番禺东沙大桥的设计方案—钢箱系杆拱桥为工程背景,通过对其进行稳定性分析,讨论了各种因素对大跨度钢拱桥稳定性的影响,为以后同类桥型的设计提供有益的建议。 稳定问题通常分为两类,第一类稳定问题最后归结为求特征值问题,其计算比较简单;但由于材料非线性、几何非线性和初始缺陷的影响,第二类稳定问题即极限承载力问题更符合实际,本文以现有理论为指导,从特征值稳定和极限承载力两方面出发,通过有限元程序分析了几何非线性和材料非线性对拱桥极限承载力的影响;拱肋内倾对拱桥稳定及极限承载力的影响;横向风载对拱桥极限承载力的影响。 通过有限元理论计算结果表明,当采用截面刚度较大的拱肋、风撑以及较大的宽跨比时,拱桥结构的自重将远远大于运营时的车辆荷载和风荷载,拱桥面外稳定高于面内稳定,拱桥的面内稳定将控制设计。 在取定的初始几何缺陷下,线性特征值屈曲分析和几何非线性屈曲分析结果相差较小;由于材料非线性的影响,非线性稳定分析的稳定安全系数大大低于特征值屈曲分析的结果,线性特征值屈曲分析可能产生非保守的结果。 当拱肋内倾角在11度以内时拱桥的线性稳定系数随倾角的增大将增大,倾角再增加将降低稳定系数。实际桥梁设计时,应综合考虑选用适当的拱肋倾角。 当此类拱桥出现面内稳定控制设计时,横向风载的作用对拱桥的稳定系数和极限承载力影响较小。抗风并非设计控制因素。因此,在风荷载比较大的地方可以考虑采用由面内稳定性控制设计的同类拱桥。 本文只是分析了各因素单独作用对拱桥稳定的影响,未考虑各因素间的耦合作用。对于拱桥处于施工中不利状态时,要仔细验算其风的稳定性。实际风载并不是静态的,而是动态的,风载作用也是非线性的。对温度荷载的考虑本文仅考虑体系同时升降温而未考虑局部温差影响,另外未考虑钢材焊更多还原

【Abstract】 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.更多还原