索桁结构在铁路专用悬索桥中的初步研究

发布时间：2018-03-03 20:34

本文选题：索桁结构　切入点：铁路悬索桥　出处：《华中科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：索桁体系悬索桥作为一种新型的“拉-拉”体系桥梁结构,在活载-恒载比值较大情况下,与普通悬索桥相比显示出更好的结构行为,因而在铁路桥梁领域具有较好的应用前景。本文针对单跨索桁结构铁路专用悬索桥结构体系进行力学行为分析和概念设计研究,尝试为该类桥梁的初步设计提供有价值的借鉴和参考。以240m单跨钢桁铁路专用悬索桥为工程背景,采用大型有限元计算软件Midas Civil建立了该桥的空间有限元计算模型,对传统单跨铁路专用悬索桥和索桁结构铁路专用悬索桥进行了初始成桥状态、动力特性及移动荷载作用下桥梁整体刚度等问题的分析研究,得出以下结论:(1)初始成桥状态下,索桁结构悬索桥中主缆张力高于传统悬索桥,即其主缆的重力刚度相对更大,具有更好的桥梁整体高度;(2)动力特性和振型分析表明,与普通悬索桥相比,增设桁架索可以提高悬索桥体系的竖向刚度和横向刚度;(3)移动荷载作用下,与普通悬索桥相比,索桁结构悬索桥的跨中挠度值更小,且主缆、吊杆及索塔的内力、应力增量也更小,抗疲劳能力更强。(4)在保证两者主缆、吊杆总内力接近的情况下,与普通悬索桥相比,索桁结构悬索桥具有更好的整体刚度,显示其在铁路桥梁的具有更好的应用前景。
[Abstract]:Cable truss suspension bridge, as a new type of "pull-pull" system bridge structure, shows better structural behavior than ordinary suspension bridge when the ratio of live load to dead load is large. Therefore, it has a good application prospect in the field of railway bridges. In this paper, the mechanical behavior analysis and conceptual design of single-span cable-truss suspension bridge system are studied. This paper attempts to provide valuable reference for the preliminary design of this kind of bridge. Taking the 240m single-span steel truss railway suspension bridge as the engineering background, the spatial finite element calculation model of the bridge is established by using the large-scale finite element calculation software Midas Civil. In this paper, the initial bridge state, the dynamic characteristics and the overall stiffness of the bridge under moving load are analyzed and studied for the traditional single-span railway suspension bridge and the cable truss structure railway special suspension bridge. The following conclusions are drawn under the initial bridge completion state. The tension of main cable in cable-truss suspension bridge is higher than that of traditional suspension bridge, that is, the gravity stiffness of the main cable is relatively larger, and the cable has better dynamic characteristics and vibration mode analysis of the whole bridge, which shows that compared with the ordinary suspension bridge, the tension of the main cable in the cable truss suspension bridge is higher than that of the conventional suspension bridge. The addition of truss cable can improve the vertical and lateral stiffness of suspension bridge system under moving load. Compared with ordinary suspension bridge, the mid-span deflection of cable-truss structure suspension bridge is smaller, and the internal force of main cable, suspension rod and cable tower is smaller than that of ordinary suspension bridge. The stress increment is also smaller, and the fatigue resistance is stronger. 4) under the condition that the total internal force of the two main cables and suspenders is close, the cable-truss suspension bridge has better overall stiffness than the common suspension bridge. It shows that it has a better application prospect in railway bridges.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U448.25

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