【作者】 李熠；

【导师】 颜东煌； 李学文；

【作者基本信息】 长沙理工大学 ， 桥梁与隧道工程， 2009， 硕士

【摘要】 大跨度斜拉桥是由主梁、塔柱、拉索三种基本构件组成的高次超静定柔性结构体系。其成桥内力状态具有多样性,而成桥内力分布的好坏是衡量设计优劣的重要指标之一。一旦斜拉桥结构体系确定,总能找出一组斜拉索索力,使结构体系在确定荷载作用下,某种反应成桥受力状态的目标达到最优,这就是该目标下的合理成桥状态。关于如何确定PC斜拉桥的成桥状态,工程师们已总结出很多的方法,这些方法各有特点及条件,本文结合忠县长江大桥的设计,综合采用最小弯曲能量法和应力平衡法来确定其成桥状态。针对最小二乘法调索要求的主梁弯矩控制条件,以主梁恒载弯矩可行域作为约束,综合考虑主塔受力、边墩辅助墩反力及索力均匀性,以成桥索力作为变量,建立优化模型,求解优化问题,从而得到合理成桥状态。该方法是最小弯曲能量法和应力平衡法的结合点。最后,以忠县长江大桥为例,详细介绍了用综合法确定大跨度PC斜拉桥成桥状态的步骤,得到的结果为下一步确定施工状态等工作奠定了基础,对斜拉桥的建设具有一定的参考意义。并且对不同成桥状态下收缩徐变对主梁弯矩的影响进行了分析。本文还介绍了施工状态的确定方法、施工过程控制的内容以及忠县长江大桥的施工方案,并结合影响斜拉桥合理成桥状态的因素,提出为确保实现成桥状态对施工的主要技术指标要求。更多还原

【Abstract】 The long-span cable-stayed bridge,a kind of indeterminate flexible structure with many redundant degrees,consists of three basic members:girder,tower and cables.Its’internal forces are not unique under finished state.Weather the inter forces are reasonable decides the level of this design.If the structure and loading are fixed,we always can make out a set of cable forces to make some aims that response the force state of finished structure optimum under fixed structure and loadings.This is the reasonable finished state under this aim.Engineers have concluded many methods to determine the reasonable finished state of prestressed concrete cable-stayed bridge.Each method has its character and condition.In this paper,we take the design of Zhongxian Yangtze River Bridge for example,proposed a comprehensive method that uses both the Minimum Bending Energy Method and the Stress-Balance Method to determining the reasonable finished state of this bridge.In use of the comprehensive method,the Least Squares Method is used to adjust the cable forces,under the controlling conditions according to the moment of main beam. Taking the cable forces of the finished bridge as variables,we can form an optimization model which is subjected to the restriction considering the requirements of uniform of the cable forces,the resistance of the side and assistant piers,the bending forces of the towers and the dead moment feasible field of the main beam.Make out the optimization model and then attain a reasonable finished state.This method is the combination of the Minimum Bending Energy Method and the Stress-Balance Method.In the end,taking the Zhongxian Yangtze River Bridge as example,introduced the step of the determination of the reasonable finished state of the long-span prestressed concrete cable-stayed bridges by the comprehensive method in detail.The result has laid the foundation on the next step of the determination of the construction state,and has the reference value to the constructions of cable-stayed bridges.And the influence of shrinkage and creep to the main beam bending moment which under the different finished state is analyzed,too.Finally,the method of the determination of the construction state,the contents of construction controlling and the method of construction of the Zhongxian Yangtze River Bridge have been introduced in this paper.According to the influential factors of the reasonable finished state of the cable-stayed bridges,this paper has gave the main technical requirement of construction.更多还原