中承式拱桥吊杆疲劳研究

发布时间：2018-05-31 05:06

本文选题：中承式拱桥 + 吊杆　；参考：《沈阳建筑大学》2015年硕士论文

【摘要】：19世纪后,中承式拱桥以其特有的造型魅力和结构特点在我国迅猛发展,已经成为我国的主要桥型之一。吊杆是中承式拱桥的重要传力构件,因其尺寸小、构件组成部分多、对疲劳腐蚀因素比较敏感,所以吊杆及其组件的运营状态相当复杂。它的正常与否决定了整个桥梁的安全运营和寿命长短。但是目前的桥梁设计理论并没有跟上拱桥的发展,对吊杆的设计准则、服役损伤、寿命预判等都没有统一而科学的规范。再加上桥梁设计人员对吊杆的受力重视不足,忽视对吊杆疲劳和腐蚀问题的控制,对影响吊杆疲劳的因素没有进行过系统全面的研究,因此吊杆破损的现象屡屡发生。为此,本文在参考、总结已有研究成果的基础上,结合沈阳一既有桥梁,对吊杆的荷载行为、吊杆的静动力特性、影响吊杆的疲劳因素进行了较为深入、全面的研究。本文首先概述了拱桥的发展现状、特点以及分类,对吊杆在恒、活作用下的静、动力行为进行了分析,又对吊杆的疲劳问题作了较为详尽的阐述,说明了疲劳失效是吊杆破损的主要原因,介绍了疲劳破坏与静力破坏的区别,总结了吊杆破损的原因和机理,给出了吊杆目前的吊杆防护方法,对疲劳累积损伤理论以及吊杆的腐蚀疲劳进行了详细的介绍,最后结合工程实例,利用有限元分析软件对包括吊杆的间距、吊杆的位置以及吊杆内钢丝材质的三个影响吊杆疲劳的因素进行对比计算分析,得出以下结论：(1)适当减小吊杆间距不但会减小吊杆的应力和应力幅,而且对改善全桥的整体受力情况都是有益的。但间距太小也对吊杆的疲劳产生不利影响,因此间距应在4-10m的范围内；(2)短吊杆的破坏问题不仅是荷载疲劳的原因,是由其自身刚度大、变形大以及构造等各方面综合作用的结果,最大的应力和应力幅值基本出现在1/4跨和跨中之间的位置上；(3)矢跨比对吊杆受力影响极其微小,在设计的时候确定矢跨比主要考虑其对拱肋和主梁整体受力的影响,可以忽略其对吊杆疲劳的影响。吊杆疲劳问题越来越受到人们的重视,随着时间的推移,越来越多的桥梁采用中承式拱桥的桥型,同样吊杆的疲劳问题也会越来越多样化,本文的研究成果可对目前和以后的桥梁设计工作提供参考和指导,具有广泛的应用价值和前景。
[Abstract]:After the 19th century, the through arch bridge has become one of the main bridge types in our country because of its unique shape charm and structure characteristics. The suspension rod is an important force transfer component of the through arch bridge. Because of its small size, many component components and sensitive to fatigue corrosion factors, the operation state of the suspender and its components is quite complex. Whether it is normal or not determines the safe operation and life span of the whole bridge. However, the current theory of bridge design has not kept up with the development of arch bridge, and there are no unified and scientific standards for the design criteria of suspenders, service injury, life prediction and so on. In addition, bridge designers pay less attention to the stress of the suspenders, ignore the control of the fatigue and corrosion of the suspenders, and have not carried out systematic and comprehensive research on the factors affecting the fatigue of the suspenders, so the phenomenon of the breakage of the suspenders occurs frequently. Therefore, on the basis of the reference and summary of the existing research results, combined with an existing bridge in Shenyang, the load behavior of the suspender, the static and dynamic characteristics of the suspender, and the fatigue factors affecting the suspender are deeply and comprehensively studied in this paper. In this paper, the development status, characteristics and classification of arch bridges are summarized. The static and dynamic behaviors of suspenders under constant and active action are analyzed, and the fatigue problems of suspenders are described in detail. This paper explains that fatigue failure is the main reason for the failure of suspenders, introduces the difference between fatigue failure and static failure, summarizes the causes and mechanism of the breakage of suspenders, and gives the current protection methods of suspenders. The fatigue cumulative damage theory and corrosion fatigue of the suspender are introduced in detail. Finally, the distance between the suspenders is analyzed by the finite element analysis software combined with an engineering example. The position of the suspender and the three factors affecting the fatigue of the steel wire in the suspender are compared and analyzed. The following conclusion is drawn: 1) decreasing the spacing between the suspenders will not only reduce the stress and stress amplitude of the suspenders, but also reduce the stress amplitude of the suspenders. Moreover, it is beneficial to improve the whole load condition of the whole bridge. However, too small spacing also has a negative effect on the fatigue of suspenders, so the failure problem of short suspenders should be in the range of 4-10 m) the failure problem of short suspenders is not only the cause of fatigue, but also due to the large stiffness of the suspenders themselves. As a result of the combined action of large deformation and structure, the maximum stress and stress amplitude basically appear in the position between the 1 / 4 span and the middle span. The sagittal / span ratio has very little effect on the stress of the suspender. In the design, the influence of rise-span ratio on the stress of arch rib and main beam is considered, and the influence on the fatigue of suspender can be neglected. People pay more and more attention to the fatigue problem of suspenders. With the passage of time, more and more bridges adopt the bridge type of mid-through arch bridge. Similarly, the fatigue problem of suspenders will become more and more diversified. The research results of this paper can provide reference and guidance for the current and future bridge design work, and have wide application value and prospect.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.22;U441.4

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