结构静定特性对桥梁结构行为的影响

Impacts of Statically Determinate Property of Structures onto Bridge Structural Behaviors

通过分析结构几何组成与结构静定特性的关系,论证了几何可变体系用于工程结构特别是大跨度桥梁结构的适宜性。从解的存在性及惟一性、非荷载作用的影响、结构刚度的影响以及平衡力系的影响等方面对静定结构和超静定结构的特性进行了比较。分析了相对刚度对超静定桥梁结构行为的影响。当结构的相对刚度过于悬殊时,桥梁结构行为会表现出某种奇异的特性。以连续刚构桥的墩柱以及悬索桥的加劲梁和主塔受力为例,阐述了这些部位的刚度越大,其受力越是不利。

From discussing the relations between geometrical component and statically determinate property of structures, the suitability was explained in this paper to employ geometrical unstable systems in long-span bridge structures. The comparisons between structural characters of statically and hyperstatically determinate structures were carried out in the aspects of existence and uniqueness of solutions, effects of non-load action, effects of structural stiffness, effects of equilibrium force systems, and so on. Finally, the influence of structural relative stiffness to hyperstatically determinate structures were analyzed. It was realized that the structures with great disparity of relative stiffness will exhibit some unusual behaviors. As typical cases, for the piers of continuous rigid bridges, and the towers and stiffening girders of suspension bridges, the bigger the stiffness constant and section dimensions, the more unfavorable to their stress situations.