大跨径PC连续刚构桥的空间受力分析

发布时间：2018-06-08 07:09

本文选题：大跨径PC连续刚构桥 + 裂缝　；参考：《长安大学》2014年硕士论文

【摘要】：近年来，轻巧纤细的桥梁结构受到了设计师们的青睐，并且桥梁的载重和跨径也在不断增加。连续刚构桥由于在这些方面有着得天独厚的优势而被大量采用。但随着跨径的不断增加，在后期运营中梁体开裂等问题也开始显现，，并存在一定普遍性，因此，对大跨径PC连续刚构桥的空间受力分析就显得尤为重要。本文主要完成了如下工作： 1）阐述了连续刚构桥的发展概况和体系特征，探讨了目前连续刚构桥中易出现的跨中下挠、梁体开裂这两大问题，并提出了对于大跨径PC连续刚构桥进行空间受力分析的必要性和意义。介绍了箱梁空间受力的特点和分析方法以及预应力钢束的设计方法和计算理论。 2）以跨径为55m+2×100m+55m的某座预应力混凝土连续刚构桥为工程背景，采用有限元软件Midas/Civil建立了全桥梁单元整体模型，实现了对全桥的整体受力情况的模拟，分析了全桥梁单元模型的静力特性。 3）采用有限元软件Midas/FEA对桥梁进行局部空间实体单元模型的仿真分析，这里选取了构造形式和受力较为复杂的主墩0号块以及延伸单元作为研究对象，进一步分析了连续刚构桥的空间受力特性，并与梁单元模型作对比分析，结果表明目前工程设计常采用的梁单元模型计算并不符合桥梁局部位置的真实受力情况，这也是箱梁容易开裂的原因之一，而实体单元模型则可以反映出箱梁腹板中锚固区位置等一些特殊截面的局部应力。 4）最后详细分析了竖向预应力作用下箱梁腹板的受力情况，并研究了竖向预应力钢筋的作用理论。通过对实体模型的分析，讨论了预应力钢束的预加应力在梁体中存在一定扩散角度，并详细分析了预应力的扩散效应，由此找到箱梁腹板存在的预应力盲区问题。通过对不同间距布置竖向预应力钢筋的对比分析，研究了在充分考虑预应力的扩散效应作用下，竖向预应力钢筋在腹板中的合理间距问题。
[Abstract]:In recent years, the light and slender bridge structure has been favored by designers, and the bridge load and span are increasing. Continuous rigid frame bridges are widely used because of their unique advantages in these aspects. However, with the continuous increase of span, the problems of beam cracking begin to appear in the later period of operation, and there is a certain degree of universality. Therefore, it is particularly important to analyze the spatial force of PC continuous rigid frame bridge with long span. The main work of this paper is as follows: 1) the development situation and system characteristics of continuous rigid frame bridge are expounded, and the two problems, such as deflection in span and beam cracking, which are easy to appear in continuous rigid frame bridge at present, are discussed. The necessity and significance of spatial stress analysis for PC continuous rigid frame bridge with long span are put forward. This paper introduces the characteristics and analysis method of space stress of box girder, the design method and calculation theory of prestressed steel beam. 2) taking a prestressed concrete continuous rigid frame bridge with span of 55m 2 脳 100m 55m as the engineering background. The finite element software Midas / Civil is used to establish the whole model of the whole bridge element. The static characteristics of the whole bridge element model are analyzed. 3) the finite element software Midas / FEA is used to simulate the local spatial solid element model of the bridge. In this paper, the spatial stress characteristics of continuous rigid frame bridge are further analyzed and compared with the beam element model by selecting block 0 of the main pier and the extension element of the main pier with more complicated structural form and force as the research object. The results show that the calculation of beam element model, which is often used in engineering design, does not accord with the actual stress condition of the local position of the bridge, which is one of the reasons why the box girder is prone to crack. The solid element model can reflect the local stress of some special sections such as the anchoring area in the box girder web. 4) finally, the stress of the box girder web under the action of vertical prestress is analyzed in detail. The action theory of vertical prestressed steel bar is also studied. Based on the analysis of solid model, the diffusion angle of prestress of prestressed steel bundle in beam is discussed, and the diffusion effect of prestress is analyzed in detail, and the problem of prestressing blind zone in box girder web is found out. Based on the comparative analysis of the vertical prestressed steel bars with different spacing, the reasonable spacing of the vertical prestressed bars in web plates is studied under the full consideration of the effect of prestress diffusion.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.5;U448.23

【参考文献】