提高拱梁固结拱桥刚度的有效方法

拱梁固结拱桥通过主梁作为刚性系杆来平衡拱的推力,但也带来结构刚度下降的不利影响,这使该类拱桥在高速铁路上的应用受到了一定的限制,为了解决这个问题,提出一种新的拱桥加以解决.其做法是,首先在每条拱肋和主梁之间增加10根刚性斜杆与拱肋及主梁节段形成11个三角形结构,尽可能通过三角形角点对拱肋均匀约束,提高拱肋的线刚度;其次,保证有三角形角点落在原结构拱肋位移包络图的最大位移处及主梁跨中位置处,使主梁或拱肋的薄弱点得到加强,线刚度亦得到提高.研究表明,新型拱桥在材料增加很少甚至相同的条件下,其整体刚度均能大幅度提高.还对疲劳和温度响应作了深入的研究,通过有限元分析表明,该结构对疲劳和温度也有很好的适应性.新型拱桥良好的刚度特性对高速铁路桥特别适用.

An Effective Method to Improve the Stiffness of Arch-beam Fixed Arch Bridges

The main beam of a Arch-beam fixed arch bridge acts as a rigid tie rod to balance the thrust of archs, but it also has the adverse effect of structural stiffness decrease. This has limited the application of this type of arch bridge on high-speed railways. In order to solve this problem, this paper proposes a new arch bridge. The method is, first of all, to add 10 rigid diagonal bars between each ribs and the main beam to form 11 triangle structures with the main beam and the each ribs segments. As far as possible, the arch ribs and the main beam are equally divided by triangular corner points so that the line stiffness of the arch ribs and the main beam are improved. Secondly, according to the original structure displacement envelope diagram, it is guaranteed that the triangular corner points fall at the position of maximum displacement and the mid-span of main beam so that the weakness of arch ribs is strengthened. Studies have shown that the overall stiffness of the new arch bridge can be significantly improved under the condition that the material increases little or even the same. In this paper, the fatigue and temperature responses are also discussed in detail, and finite element analysis shows that the structure also has good adaptability to fatigue and temperature. And the superior stiffness characteristics of the new arch bridge are particularly suitable for high-speed railway bridges.