斜靠式拱桥结构体系与稳定性分析

【作者】 阳霞；

【导师】 任伟新；

【作者基本信息】 中南大学 ， 土木工程， 2011， 硕士

【摘要】 斜靠式拱桥是一种新型的无风撑拱桥,由于拱肋是由主拱和斜靠拱构成的组合拱,是一种复杂的空间梁拱组合体系,确定合理的结构设计参数和主拱与斜拱共同作用的侧倾稳定性是斜靠式拱桥设计中的关键问题。本文以设计中的湖南常德市洞庭大道跨新河渠斜靠式拱桥为工程背景,建立了该桥的空间有限元模型,对斜靠式拱桥主要结构设计参数及稳定性进行了深入的探讨,研究成果可为斜靠式拱桥设计时参考。论文的主要工作和结论包括：1.按结构自重(恒载)、活载正载(车辆荷载满载+人群荷载满载)和活载偏载(车辆荷载偏载+人群荷载偏载)三种荷载,研究斜靠式拱桥结构的关键设计参数,矢跨比、主拱与主梁的刚度比、主斜拱的刚度比、拱轴线型,对结构内力的影响规律。2.以圆弧拱为研究对象,采用能量法推导了组合拱(主拱和斜拱)面外稳定的临界计算公式。通过数值算例和参数分析,从机理上研究斜拱对竖拱(主拱)面外(侧倾)失稳的影响。3.通过空间有限元模型,系统地研究主斜拱之间横撑的刚度、数量和位置、斜拱与主拱的刚度比等参数对斜靠式拱稳定性的影响规律。结果表明,主拱作为整座桥梁的主要承重构件,而斜拱主要提供横向稳定性,形成了一个受力合理、结构稳定的体系。更多还原

【Abstract】 The double X-arch bridge is a new type of arch bridges without the traditional transverse bracing. It is a complicated spatial combination system bridge of beam and arch contributed to the arch ribs comprised of the main arches and double X-arches. In the design and construction analysis of double X-arch bridge, it’s crucial to ascertain the structural design parameters and the out-plane stability of the main arch together with the inclined arch. This research bases on a double X-arch bridge crossing the Xinhe River Changde city, Hunan province. The three dimensional finite element model of this bridge is developed. The main design parameters and stability of this bridge is deeply discussed. The outcomes of this research can be references to the design of double X-arch bridge. Specifically, the main work of this thesis is showed as following:1. How the key structural design parameters, such as the ratio of rise to span, the ratio of rigidity of main arch to girder, the ratio of rigidity of inclined arch to main arch, and the type of arch axis, etc. influence the internal force of the bridge is investigated when the bridge is subjected to the dead weight of structure (dead load), symmetric live load (the capacity load of vehicle loading and crowd loading) and eccentric live load respectively (the eccentric load of vehicle loading and crowd loading).2. On the basis of the circular-arch, the calculation formula of out-plane stability critical load of combined arch (main arch and inclined arch) by means of energy method. Numerical examples and parameter analysis are carried to investigate how the inclined arch affects the stability of the main arch is studied.3. Also, systematic research is performed to discuss the effect of several parameters, such as cross-brace rigidity between main arch and inclined arch, quantity and position of the cross-brace, stiffness ratio of inclined, on the stability of double X-arch. It is confirmed that the main arches are the core structural members and the inclined have a significant positive effect on the out-plane stability of the bridge, which contributes a reasonable system in terms of load mechanism and stability更多还原