大跨度钢桁架拱桥抗震性能分析

发布时间：2019-04-25 12:24

【摘要】：对于处于地震频发但地形平坦开阔的平原地区来说,刚柔相济的钢桁架拱桥是一种相对较为理想的大跨度桥梁方案。由于钢桁架拱桥结构的复杂性、行波效应以及桥头堡的影响,其地震响应较为复杂,因此对大跨度钢桁架拱桥进行抗震性能研究是必要的。文章首先介绍了大跨度钢桁架拱桥的发展情况、结构形式和特征并简述了抗震性能相关的研究现状。然后,以某工程项目作为背景,计算分析该结构在静力状况下受几何非线性的影响程度,并分析了该结构的动力特性。最后通过反应谱分析方法、一致激励时程分析方法、考虑行波效应的时程分析方法、考虑桥头堡影响的精细计算模型来对大跨度钢桁架拱桥进行抗震性能分析。通过研究发现:钢桁架拱桥整体刚度较大,几何非线性的影响较小,但是横向刚度相对于纵向刚度较小,横桥向地震响应较大,在进行结构设计时应注意加强横向刚度;该桥型频带较窄,在振型组合时应考虑振型之间的耦合,同时该桥型高阶振型的影响不可忽略;当地震作用由E1提升到E2时,靠近拱脚位置的杆件应力变化更为显著;行波效应对大跨度钢桁架拱桥影响显著,在进行大跨度钢桁架拱桥抗震性能分析时,应考虑行波效应的影响,各个构件中靠近拱脚处的杆件对行波效应更为敏感;由于顺桥向地震激励与竖向激励的耦合作用,考虑竖向地震作用之后,行波效应对结构拱顶和拱脚处面内弯矩影响变小,行波效应对结构拱脚处面外弯矩影响变大;为了偏于安全,在进行大跨度钢桁架拱桥抗震性能分析时,应计入桥头堡等结构的影响。
[Abstract]:The steel truss arch bridge, which is rigid and flexible, is a relatively ideal long-span bridge scheme for plain areas where earthquakes occur frequently but the terrain is flat and open. Because of the complexity of steel truss arch bridge structure, the traveling wave effect and the influence of bridge head fortress, the seismic response of steel truss arch bridge is more complex, so it is necessary to study the seismic performance of long span steel truss arch bridge. In this paper, the development, structure form and characteristics of long-span steel truss arch bridge are introduced, and the research status related to seismic performance is briefly introduced. Then, taking a project as the background, the influence of geometric nonlinearity on the structure under static condition is calculated and analyzed, and the dynamic characteristics of the structure are analyzed. Finally, the seismic performance of long-span steel truss arch bridge is analyzed by response spectrum analysis method, uniform excitation time-history analysis method, time-history analysis method considering traveling wave effect, and precise calculation model considering the effect of bridgehead fortress on the seismic performance of long-span steel truss arch bridge. It is found that the overall stiffness of steel truss arch bridge is larger and the influence of geometric nonlinearity is small, but the transverse stiffness is smaller than the longitudinal stiffness and the seismic response of the transverse bridge is larger. Therefore, the transverse stiffness should be strengthened in the structural design. The frequency band of the bridge is narrow, the coupling between the modes should be considered when the vibration modes are combined, and the influence of the high-order mode shape of the bridge type should not be ignored, when the earthquake action is raised from E1 to E2, the stress change of the member near the arch foot is more obvious. The traveling wave effect has significant effect on the long-span steel truss arch bridge. In the seismic performance analysis of the long-span steel truss arch bridge, the traveling wave effect should be considered, and the members near the arch foot in each member are more sensitive to the traveling wave effect. Because of the coupling action of along-bridge seismic excitation and vertical excitation, the effect of traveling wave effect on the in-plane bending moment at arch top and arch foot becomes smaller, and the effect of traveling wave effect on out-of-plane bending moment at arch foot becomes larger after considering vertical earthquake action. In order to be safe, the seismic behavior analysis of long-span steel truss arch bridge should take into account the influence of bridgehead and other structures.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U442.55;U448.22

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