连续刚构桥梁的动力优化研究

发布时间：2018-03-25 02:05

本文选题：高墩大跨连续刚构桥　切入点：抗震性能　出处：《昆明理工大学》2015年硕士论文

【摘要】：预应力混凝土连续刚构桥梁是一种墩梁固结的结构形式,从结构力学上来讲是一种超静定结构。其优点较多：整体性好、跨度大；结构连续无伸缩缝、行车平顺；相关材料用量省；施工方便；墩顶处的负弯矩消减了跨中的正弯矩；能够较好的适应预应力、混凝土收缩、徐变以及温度变化产生的位移；在大跨度桥梁结构中造价相对来说低很多；结构形式纤巧,造型优美等。基于这些优点,连续刚构广泛应用于高墩大跨结构形式之中,例如对于航行要求较高的大河、深山中的V沟等复杂地形,连续刚构的应用就大量存在。由于此种桥型的大量应用,相关方面设计要求非常高,但是,这种桥型的设计工作量大,结构中的设计参数大多是经验得来的,这是不合理的。高墩大跨径的PC连续刚构桥广泛应用于云贵高原西南地区地形复杂的地方,而且这样的地区地震活动频繁,大震重现期较短,并且连续刚构桥基于抗震性能的参数优化又少之又少,利用经验值对连续刚构桥进行设计既不经济,又没理论依据,结构安全储备度尚不可知。因此,对高墩大跨径PC连续刚构桥基于抗震性能的参数优化有着重大的意义。本文以昆明市轿子山旅游专线公路3合同段的马过河大桥为研究背景,围绕连续刚构桥基于抗震性能的参数优化展开研究工作,主要完成的工作和结论如下：(1)介绍了地震对桥梁造成的各种各样不同程度的损害,以及地震对桥梁造成损害后的启示以及教训,同时介绍了连续刚构桥的发展历程和抗震方面的研究进程。对结构地震反应的分析方法进行了详细阐述,引出了本文所用的抗震研究方法-静力弹塑性分析方法(Pushover分析方法),并详细介绍了其方法使用的理论依据和使用方法。(2)对已经建成的连续刚构桥的参数进行整理归纳,得出相应的使用范围。根据地震的设防等级,设定目标函数。首先,利用了正交表对参数进行优化,初步得出了参数组合：边中跨比值为0.6,双薄壁墩墩间距为10m,墩厚度为4m,相应的墩壁厚度为0.7m。利用正交表在节省优化时间的前提下,又保证了优化结果的精度。(3)正交表只能在已经组合好的参数中,选出最优的参数组合来,并不能脱离这个范围,有一定的局限性。在正交表36个参数组合不变的情况下,利用神经网络和遗传算法进行求解最优值,神经网络具有很强的非线性映射能力,将训练结果保存用遗传算法进行寻优,求解出最优值。得出的最优组合是：边中跨比值为0.53,墩间距为9.56m,墩的厚度为3.99m,墩壁厚度为0.654m。
[Abstract]:Prestressed concrete continuous rigid frame bridge is a structural form of consolidation of piers and beams, which is a statically indeterminate structure in terms of structural mechanics. It has many advantages: good integrity, large span, continuous structure without expansion joints, smooth running; The negative bending moment at the top of the pier reduces the positive moment in the span, and can adapt to the displacement caused by the prestress, concrete shrinkage, creep and temperature change. In the long span bridge structure, the cost is much lower, the structure form is slender, the shape is beautiful and so on. Based on these advantages, continuous rigid frame is widely used in the form of long span structure with high piers, such as the river with high navigation requirements. The application of continuous rigid frame exists in a large number of complex terrain such as V-ditch in the deep mountains. Because of the extensive application of this kind of bridge, the design requirements of related aspects are very high, but the design workload of this kind of bridge is great. The design parameters of the structure are mostly experienced, which is unreasonable. The PC continuous rigid frame bridge with high piers and long span is widely used in the places with complicated topography in the southwest of Yunnan-Guizhou Plateau, and the seismic activity is frequent in this area. The recurrence period of large earthquake is short, and the parameter optimization of continuous rigid frame bridge based on seismic performance is rare. It is neither economical nor theoretical basis to design continuous rigid frame bridge by using the experience value. Therefore, the degree of structural safety reserve is unknown. It is of great significance to optimize the parameters of PC continuous rigid frame bridge with high piers and long span based on seismic performance. The research work on parameter optimization based on seismic performance of continuous rigid frame bridge is carried out. The main work and conclusions are as follows: 1) the various damage caused by earthquake to bridge is introduced. At the same time, the development history and seismic research process of continuous rigid frame bridge are introduced. The analysis method of seismic response of structure is described in detail. The static elastic-plastic analysis method and pushover analysis method used in this paper are introduced. The theoretical basis and application method of the method are introduced in detail. The parameters of the completed continuous rigid frame bridge are summarized. Get the corresponding range of use. According to the level of earthquake fortification, set the objective function. First, the orthogonal table is used to optimize the parameters, The parameter combination is obtained: the ratio of side to middle span is 0.6, the spacing of double thin-walled piers is 10m, the thickness of piers is 4m, and the corresponding thickness of piers is 0.7m.The orthogonal table is used to save optimization time. It also ensures the accuracy of the optimization result. (3) the orthogonal table can only select the optimal parameter combination among the parameters that have already been assembled, which is not out of this range, and has certain limitations. When the 36 parameter combinations of orthogonal table are not changed, Using neural network and genetic algorithm to solve the optimal value, neural network has a strong ability of nonlinear mapping, the training results are saved using genetic algorithm for optimization, The optimum combination is: the ratio of side to middle span is 0.53, the distance between piers is 9.56m, the thickness of piers is 3.99m, and the thickness of pier wall is 0.654m.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.23

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