【作者】 朱鹏志；

【导师】 余钱华；

【作者基本信息】 长沙理工大学 ， 桥梁与隧道工程， 2007， 硕士

【摘要】 随着高速公路交通的发展,国内外修建了很多大跨度桥梁,预应力混凝土连续刚构桥应运而生。特别我国西部是山区V型峡谷地形居多,很适合修建连续刚构桥。随着已建成的连续刚构桥出现的一系列类似问题,跨中下挠严重和腹板局部开裂。本文将从布束方案入手,探讨连续刚构桥合理布束问题和预应力的优化设计,以三跨对称的广西龙潭库区布柳河大桥和四跨不对称的湘西不二门大桥为依托工程,从合理内力分布角度来探讨跨中下挠问题,对其中三向布束的湘西不二门大桥,建立全桥实体模型,进行腹板主拉应力进行研究。本文研究的主要内容有:1.针对现阶段的几种布束方案,本文分析了各自的优缺点;从混凝土强度准则的角度来分析在连续刚构桥竖向预应力的设计问题。2.连续刚构桥预应力优化设计和下弯束参数优化。3.建立了基于BRanaysis程序的空间杆系有限元模型,对布柳河大桥和不二门大桥下挠问题进行了研究。通过调整预应力大小来控制结构恒载内力,分析桥梁上部结构恒载内力分布对桥梁营运过程中时效弹性下挠的影响。其中对不同布束方案的布柳河大桥进行了经济性分析。4.采用ANSYS通用有限元软件,以三向布束的湘西不二门大桥为例,介绍利用实体单元模拟连续刚构桥施工过程的计算方法,实现了整个施工过程的仿真计算。将这种方法计算的结果和空间梁单元的模拟计算结果进行比较,分析这种方法作为辅助计算的合理性和优点。最后对成桥状态腹板主拉应力及竖向预应力损失对腹板主拉应力的敏感程度进行研究。更多还原

【Abstract】 With the development of highway, many large span bridges, including pre-stressing concrete continuous rigid frame bridges, are built at home and abroad. Especially in the west of China where V-shaped gorge is of the main terrain feature, such bridges are very appropriate. A series of similar problems of this kind of bridge exist, such as serious excessive deflection at the span centre and some local cracks in sternum. Started with the program of layout of strands, the problems of reasonable layout of pre-stressing strands and optimization design of pre-stressing force are discussed in this thesis. Take the symmetric three-span Buliuhe Bridge in the surrounding area of Longtan Reservoir in Guangxi and asymmetric four-span Buermen Bridge in the west of Hunan for instance. The problem of deflection at the span centre is discussed from the point of view of reasonable inner force distribution. The solid model of Buermen Bridge of which strands are laid in three directions is established in order to carry out the research on the principal tensile stress of sternum. The main content of research in the thesis is as followers:1. Advantages and disadvantages of several different programs on how to lay bars at present are analyzed.The problem of vertical pre-stressing force design of continuous rigid frame bridge is analyzed according to concrete strength criterion.2. The optimization design of pre-stressing force of the PC continuous rigid frame bridge and the coefficient optimization of low bended bars are discussed.3. The special braced construction model is founded based on Poweranalysis program. The deflection of Buliuhe Bridge and Buermen Bridge is further studied. By adjusting the size of different pre-stressing force to control permanent load inner force distribution of the superstructure in the bridge, and further analyze the effect of aging elastic deflection influenced by this inner force distribution during the process of bridge service. Take Buliuhe Bridge for example analyze different economic design project of pre-stressing strands.4. Take Buermen Bridge in the west of Hunan of which strands are laid in three directions for example, the calculation method using solid elements to simulate the construction process of the continuous rigid frame bridge is proposed, and the whole construction process has been simulated and calculated. As an assistant method, its validity and superiority have been proved, compared with the result of the other method using spatial beam element. Finally, the principal tensile stress of the sternum and its sensitivity toward the loss of vertical pre-stressing force at the phrase of construction are studied.更多还原