武汉天兴洲公铁两用长江大桥空间几何非线性有限元仿真分析

【作者】 刘东芳；

【导师】 叶梅新；

【作者基本信息】 中南大学 ， 固体力学， 2007， 硕士

【摘要】 武汉天兴洲公铁两用长江大桥主桥设计为98+196+504+196+98m双塔三索面三主桁斜拉桥，上下分两层，上层为6车道公路，下层为4线铁路，两线客运专线，两线Ⅰ级铁路干线。铁路桥面采用纵横梁体系，有碴桥面。每两个节间设置一道伸缩纵梁，每道伸缩纵梁上方混凝土板开一条缝。该桥是我国第一座下承式钢—混凝土结合有碴铁路桥面斜拉桥，也是我国武广客运专线上的关键工程。本文对武汉天兴洲公铁两用长江大桥的有限元计算方法和受力特性作了系统的研究，主要完成了以下工作：1．分析了大跨度斜拉桥几何非线性的主要影响因素，包括斜拉索的垂度效应、梁—柱效应和大位移效应，并提出有限元分析中相应的处理方法。2．建立了天兴洲公铁两用长江大桥的空间几何非线性有限元分析模型，并研究了其恒载和活载作用下的挠度和各构件的应力。结果表明：该桥刚度和强度满足要求，受力合理。设计荷载下不考虑几何非线性计算所得的各种响应都偏小，偏于不安全，但最大误差不超过8％。3．研究了季节温差和日照温差对天兴洲桥受力状态的影响。结果表明：在整体升温和整体降温作用下，虽然在靠近主跨跨中的横梁结点处产生较大的应力，但与一期恒载、二期恒载和活载组合后总应力都不超过200MPa。4．对钢—混凝土组合铁路桥面系混凝土发生徐变后，混凝土板及纵、横梁之间的应力重分布进行了研究。结果表明：混凝土徐变后混凝土桥面板的应力变小，其中上板面应力变化比较明显，下板面应力变化较小；钢纵、横梁下翼缘的应力增大，但幅度较小，应力重分布后混凝土板及钢纵、横梁上的应力仍小于规范规定值。本文的研究成果不仅为武汉天兴洲公铁两用长江大桥的设计提供了依据，其基本思想和方法也可应用于其他大型复杂钢—混凝土组合结构斜拉桥的受力状态分析。更多还原

【Abstract】 The main bridge of Wuhan TianXing-zhou highway/railway Yangtze River bridge is a double-tower, three cable planes, three main trusses cable-stayed bridge with span arrangement (98+196+504+196+98) m.The expansion longitudinal beams are designed in every two panels and slots are designed in the concrete deck over the expansion longitudinal beams.The bridge is the first steel-concrete composite cable-stayed through bridge with ballasted deck and is the key project of Wuhan-Guangzhou Passenger Transport Railway.The finite element computing method and the mechanical behavior of Wuhan Tian Xing-zhou highway/railway Yangtze River bridge were studied systemically. Main work of this paper is as follows:1. The main influence factors of geometric nonlinearity of long-span cable-stayed bridge were analyzed, including cable stay sag effect, beam-column effect and big displacement effect, and the corresponding methods were proposed.2. Geometric nonlinear space finite element models of Tian Xing-zhou highway/ railway Yangtze River bridge were established. The deflections and stresses of various members of the bridge under the dead load and the live load were studied. The results show that the rigidity is high and the stress is reasonable.3. The influence of seasonal temperature difference and sunlight-induced temperature difference to the mechanical behavior was studied. The results show that there exists large stresses at the transverse beam crunodes closing with the main span midspan on the effect of the temperature increase or decrease. But combined the above stresses with the stresses under the first dead load, the second dead load and the live load, the total stresses are less than 200MPa.4. Stresses redistribution produced by creep on the concrete of steel-concrete composite railway bridge deck were studied. The results show that stresses in concrete slab become smaller and the stresses in steel beams become larger. The stresses in concrete slab and steel beams are still smaller than the ordainment in criterion after stresses redistribution.The research results in this paper provide references for the design of Wuhan TianXing-zhou highway/railway Yangtze River bridge, the basic ideas and methods can be applied to the analysis of other big and complex steel-concrete composite structure cable-stayed bridge as well.更多还原