悬臂施工箱梁桥空间效应及腹板应力状态的精细化分析

发布时间：2019-07-09 12:06

【摘要】：在预应力混凝土箱梁桥的设计分析中,目前主要采用平面杆系计算模型,不能反映其空间受力和局部受力特点。而采用实体单元的大型通用结构分析程序(如ANSYS等)虽具有功能强大、通用性强的特点,但在分析预应力混凝土桥梁时,如果不经过二次开发,难以完成对预应力、活载、混凝土收缩徐变等模拟计算。针对这一情况,江苏省交通规划设计院历时多年开发了“预应力混凝土箱梁精细化数值模拟系统”(简称RNAS-PCBB),可以较好地进行预应力混凝土桥梁的实体元精细化分析。本文结合“预应力混凝土箱梁精细化数值模拟系统”的内核原理和应用实践,阐述了在预应力混凝土箱梁桥分析中对混凝土与钢筋的本构模型选取考虑,讨论了利用ANSYS在三维实体有限元模型中预加力的模拟方法和预应力混凝土箱梁桥的三维实体建模方法。论文以预应力混凝土箱梁桥为分析研究对象,结合某工程实例,建立了全桥空间分析模型,考虑三向预应力作用荷载工况,进行关键部位的应力状态分析。讨论了沿桥纵向不同位置截面的剪力滞效应。在模型中考虑车道荷载的偏心作用,活载正应力偏载系数沿纵桥向的规律。同时分析了腹板配束形式与应力分布的关系,指出了腹板竖向预应力与下弯束对减小腹板主拉应力的重要作用。最后研究了底板、齿板在预应力作用下的局部应力分布,提出防止底板、齿板在施工及使用过程中出现开裂的构造设计措施。研究结论对指导预应力混凝土梁桥的设计具有较好的应用参考价值。
[Abstract]:In the design and analysis of prestressed concrete box girder bridge, the plane bar system calculation model is mainly used at present, which can not reflect the characteristics of spatial force and local force. Although the large-scale general structural analysis program (such as ANSYS, etc.) with solid element has the characteristics of powerful function and strong generality, it is difficult to complete the simulation calculation of prestress, live load and concrete shrinkage and creep if the prestressed concrete bridge is analyzed without secondary development. In view of this situation, Jiangsu Traffic Planning and Design Institute has developed the Prestressed concrete Box girder Fine numerical Simulation system (RNAS-PCBB) for many years, which can carry out the fine analysis of the solid element of the prestressed concrete bridge. Based on the core principle and application practice of "Prestressed concrete Box girder refinement numerical Simulation system", this paper expounds the selection of the constitutive model of concrete and steel bar in the analysis of prestressed concrete box girder bridge, and discusses the simulation method of preloading force in three-dimensional solid finite element model by using ANSYS and the three-dimensional solid modeling method of prestressed concrete box girder bridge. In this paper, the prestressed concrete box girder bridge is taken as the analysis object, combined with an engineering example, the spatial analysis model of the whole bridge is established, and the stress state analysis of the key parts is carried out considering the load condition of the three-way prestress. The shear lag effect of different cross sections along the longitudinal direction of the bridge is discussed. Considering the eccentricity of lane load in the model, the law of live load normal stress bias coefficient along the longitudinal bridge direction is considered. At the same time, the relationship between web beam distribution and stress distribution is analyzed, and the important role of web vertical prestress and downward bending beam in reducing the main tensile stress of web is pointed out. Finally, the local stress distribution of the bottom plate and the tooth plate under the action of prestress is studied, and the structural design measures to prevent the cracking of the bottom plate and the tooth plate in the process of construction and use are put forward. The research results have good application reference value for guiding the design of prestressed concrete beam bridge.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.5;U448.213

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