【作者】 刘景生；

【导师】 钱永久；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2008， 硕士

【摘要】 近年来,随着我国综合国力的不断增强,高速公路也得到了前所未有的发展。高速度的行车要求公路上的桥梁具有较好的连续性能、较少的伸缩缝构造,以提供高速、平稳、舒适的行车条件。先简支后连续小箱梁结构体系结合了连续梁和预制梁的优点,因此得到了广泛的应用和发展。本文首先总结了先简支后连续结构体系的发展概况和研究现状,并总结了该体系的分析理论和次内力计算方法。在此基础上,针对体系转换和体系不转换结构中有争议的后连续端部浇筑顺序和后连续预应力张拉顺序问题进行了分析,提出了后连续端部的浇筑和预应力筋的张拉的“隔跨”原则。其次,以六跨一联先简支后连续桥梁为例,详细分析了结构在运营期间混凝土徐变对结构受力的影响,对影响徐变次内力的参数如:持荷时间、混凝土养护龄期、后期预应力筋长度、桥梁跨数、环境湿度因素等作出了分析,并根据分析结果对该类型桥梁的设计提出了相应的改进方案。另外,对于不同国家规范下温度梯度对该结构体系的内力影响进行分析。最后指出了下一步工作的研究重点和方向。更多还原

【Abstract】 Recently, the highway had unprecedented developed with the enhancement of comprehensive national power in our country.In order to provide fastly and comfortable driving condition, high qualities of the bridges were required in the highway.The high qualities were better continuous performance and less expansion joints. Because of the first simply then continuously supported small span box-girder bridge combines the advantages of the continuous beam bridges and the precast beam bridges, it had been widely applied and developed.Firstly, this thesis summarizes development situation, present research status, analysis theory and method of the first simply then continuously supported structure systerm.On the basis of the simulative research results, the method is applied to analyze some controversial problems(such as the concrete pouring sequence of continuous ends, the applying sequence of prestressing force) in this kinds of structural transformative/untranformative system. Some important conclusions are drawn: the concrete pouring sequence of continuous ends and the applying sequence of prestressing force should be in accordance with the principle of "interval end".Secondly, taking six-spans the first simply then continuously supported bridge for example, this paper analyzes in considerable details the effect of concrete creep upon the internal force of the structure during service period of the bridge, in which the parameters such as loading duration. concrete ages, the number of spans, the humidity of circumstance and later period length of prestressing tendons are considered, and also proposes the corresponding improvements to the design of such type of bridge structure in accordance with the analytical results obtained therefrom.Finally, on the basis of different national codes, effects of temperature gradient to this structure systerm are analyzed in the thesis and next direction and emphasis of research are pointed out .更多还原