斜靠式拱桥动力特性研究

Study on Dynamic Characteristics of Leaning-type Arch Bridge

平顶山市城东河路湛河桥是一座斜靠式钢筋混凝土箱肋拱桥,该桥内拱外倾、外拱内倾,组成组合拱肋与系杆梁、横梁组合成空间结构体系.该桥型较少见,为了了解该桥型的动力性能,需要对桥梁进行空间动力特性分析.采用ANSYS软件建立该桥梁空间有限元计算模型,计算得到桥梁前15阶振动周期和振型.计算结果表明:该种桥型的拱肋面内外刚度相差较大,横向刚度较竖向刚度弱,桥梁低阶以拱肋横向振动为主;桥梁的自振周期较大;桥梁振型较为密集.

Zhanhe Bridge of Chengdong Road in Pingdingshan is a leaning - type arch bridge. Its inner arches lean outward and its outer arches lean inward, which constitute its combinational arch ribs and make space structural system with tied beams and transverse beams. In order to acquire the dynamic characteristics of this type of bridge, which is rare in constructional application, its space dynamic characteristics need to be analyzed. According to the structural characteristics of the bridge, its space finite element computational model is set up. The first 15 orders of period and modes are obtained by the ANSYS program. The result indicates that the transverse stiffness of this bridge is smaller than its vertical stiffness and the transverse vibrations of arches occupy the main part of its lower order modes. The results reveal that there exist considerable differences of the arch ribs between the stiffness in plane and the stiffness out of plante. Meanwhile the transverse stiffness of the bridge is smaller than its vertical stiffness and the transverse vibrations of arches occupy the main part of its lower order moodes. It also incdicates that the natural vibration period of the bridge is relatively large and vibration modes are close.