下承式钢管混凝土拱桥自振特性研究

Study on Self-vibration Characteristics of Under-supported Concrete-filled Steel Tube Arch Bridge

为了对钢管混凝土拱桥进行结构优化,利用有限元通用软件ANSYS,对一座下承式钢管混凝土拱桥进行了自振特性分析。文章通过变换拱桥的矢跨比和横撑形式,来讨论了它们对结构自振特性的影响。分析发现该拱桥的振动主要有拱肋的面外横向振动、桥跨结构整体竖向振动和桥跨结构扭转振动;矢跨比对拱桥结构自振频率影响比较小;"K"形、"米"字形与"一"字形横撑比较,拱桥结构横向刚度大幅度增加。因此在钢管混凝土结构设计中可以采用"K"形、"米"字形横撑来增加拱肋横向刚度。

In order to optimize the concrete-filled steel tube arch bridge,the general finite element software ANSYS is used to analyze the self-vibration characteristics of a under-supported concrete-filled steel tube arch bridge.Through transforming the rise-span ratios of the arch bridge and forms of horizontal support,their influence on self-vibration characteristics is discussed in detail.It is found from analyses that the vibrations of the arch are main the transverse vibration outside the plane of ribs,the vertical vibration of the whole bridge structure and the torsional vibration of the bridge span,and the span ratio of the bridge structure is relatively small on the vibration frequency.While through comparing ＂K＂ form and ＂米＂ form with ＂一＂ form of horizontal support,it is found that the arch bridge would have a significant increase in lateral stiffness.Therefore,in the design of concrete structures,the horizontal with ＂K＂ form and ＂米＂ form could be used to increase the lateral stiffness of concrete-filled steel tube arch bridge.