预应力混凝土桥梁徐变计算方法及应用分析

发布时间：2018-01-09 01:22

本文关键词：预应力混凝土桥梁徐变计算方法及应用分析　出处：《长沙理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着现代桥梁建设的不断发展,预应力混凝土桥梁的结构内力分析研究也逐渐走向成熟。而在桥梁结构分析中,徐变对预应力混凝土桥梁应力应变的影响不容忽视。本文主要的研究课题是对国内常用规范中的徐变计算模式提出修正方法。虽然从不同的角度看,徐变对结构或构件的性能会产生有利或不利的效果,但是若不计徐变的影响或计算方法简单粗略,则无法定性地判断徐变的具体影响效果和程度。一方面,预应力混凝土结构或构件会因徐变而出现应变过度变化的情况,使预应力损失大大增加的不利影响。另一方面,预设桥梁预拱度的徐变变形计算是大跨度预应力混凝土桥梁的线型控制与计算中的一项十分重要的内容。所以选择合理的徐变计算模式并正确有效地运用于结构的徐变分析,是徐变计算分析领域很值得研究的一个方向。基于此,论文在开展了以下主要的研究工作:本文针对预应力混凝土桥梁的徐变内力分析,整理了国内外关于构件和结构中徐变方面的研究成果,阐述了徐变产生的机理和影响因素,综述了徐变的计算理论、计算模式和徐变对构件和结构的应力变化、桥梁线型的影响。在分析徐变的重要影响因素基础上,探讨了构件徐变参数敏感性问题。其中重点对徐变名义参数敏感性作出了分析,通过改变其增量研究徐变参数敏感性对构件应力和线型的影响程度。基于有限元分析的手段,结合国内外四个徐变计算模式,分别计算实际工程中的刚构桥的徐变,并分析四个规范得到的数据,利用其应力和位移数据,计算出四个规范计算结果中每组所对应单元应力或节点的位移结果的差值,统计得出四种规范对修正的徐变系数影响各自所占百分比的相应比例,再根据统计结果把四种规范徐变系数曲线拟合为一合理的徐变系数曲线。基于JTGD62-2004规范中的徐变系数公式,把拟合出的徐变系数曲线与原规范的徐变系数曲线进行对比,从而找出所需的函数关系,并作为修正系数Ψ的表达公式。
[Abstract]:With the continuous development of modern bridge construction, the internal force analysis of prestressed concrete bridge is gradually maturing, and in the bridge structure analysis. The influence of creep on the stress and strain of prestressed concrete bridge can not be ignored. The main research topic of this paper is to propose a modified method to calculate the creep in common codes in China, although from different angles. Creep will have favorable or unfavorable effects on the performance of structures or members. However, if the effect of creep is not taken into account or the calculation method is simple and rough, it is impossible to judge qualitatively the concrete effect and degree of creep. On the one hand. Prestressed concrete structures or members will be due to creep due to excessive strain changes, so that the loss of prestressed greatly increased the adverse impact. On the other hand. The calculation of creep deformation of preset bridge pre-arch is one of the most important contents in the linear control and calculation of long-span prestressed concrete bridge. Therefore, a reasonable creep calculation model is selected and applied to the structure correctly and effectively. Creep analysis. It is a direction worth studying in the field of creep calculation and analysis. Based on this, the thesis has carried out the following main research work: this paper aims at the analysis of creep internal force of prestressed concrete bridge. This paper summarizes the research results of creep in components and structures at home and abroad, expounds the mechanism and influencing factors of creep, and summarizes the calculation theory, calculation model and stress variation of creep on members and structures. On the basis of analyzing the important influencing factors of creep, the sensitivity of creep parameters is discussed, and the sensitivity of nominal creep parameters is mainly analyzed. By changing its increment, the influence of creep parameter sensitivity on stress and line shape of member is studied. Based on the method of finite element analysis, four creep calculation models at home and abroad are combined. The creep of the rigid frame bridge in practical engineering is calculated, and the data obtained from the four codes are analyzed, and the stress and displacement data are used. The difference between the stress of each group and the displacement of the node in each group is calculated, and the corresponding proportion of the percentage of the four codes affecting the modified creep coefficient is obtained. According to the statistical results, the creep coefficient curves of the four specifications are fitted to a reasonable creep coefficient curve, which is based on the creep coefficient formula in JTGD62-2004 code. The fitted creep coefficient curve is compared with the original standard creep coefficient curve, and the required functional relationship is found out, which can be used as the expression formula of modified coefficient 蠄.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U448.35

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