大跨度PC连续刚构桥下挠及对策分析
发布时间：2018-10-31 09:12
【摘要】：随着工程技术的发展,越来越多的大跨度连续刚构桥广泛应用在我国及世界桥梁工程中,但是由于在施工过程及运营期间中的某些原因,导致现在许多的大跨度连续刚构桥出现了各种病害,其中最为典型为主梁的下挠及由此产生的开裂,严重影响了桥梁正常使用的适用性、安全性、耐久性及使用寿命。虽然现在对于桥梁下挠的成因有很多的研究成果,但仍缺乏更深层次的认识,因此很有必要对于这方面作进一步研究。本文主要内容如下:1.简单介绍了国内外大跨度PC连续刚构桥的发展情况及下挠现状,对于目前下挠成因的相关研究理论进行了阐述。2.运用Midas-Civil有限元计算软件对山店江大桥建立了空间有限元模型,对于下挠的成因,从混凝土收缩徐变、预应力损失、开裂、超重、合拢顺序等因素进行了分析,从而得到对于主梁下挠影响程度的认识。3.根据荷载平衡思想延伸出的“恒载零弯矩法”,以山店江大桥及另两座同类三跨连续刚构桥作对比,通过各桥主梁最大悬臂阶段的自重弯矩、预应力弯矩的数值与比值情况,得到不平衡弯矩对于主梁长期挠度的影响特点。4.从降低大跨度PC连续刚构桥中所占比例较大的恒载的角度出发,由高强轻质混凝土相对普通混凝土质量较轻、收缩徐变较大的特点,确定了高强轻质混凝土在主梁上有利于改善长期挠度的合理布置范围,并研究了高强轻质混凝土的不同布置范围对主梁关键截面的应力和内力影响特点。
[Abstract]:With the development of engineering technology, more and more long-span continuous rigid frame bridges are widely used in bridge projects in China and the world, but due to some reasons in the construction process and operation period, Many long-span continuous rigid frame bridges have been caused various diseases, among which the most typical is the deflection of the main beam and the resulting cracking, which seriously affects the applicability, safety, durability and service life of the bridge. Although there are a lot of research results on the causes of bridge deflection, there is still a lack of deeper understanding, so it is necessary to do further research on this aspect. The main contents of this paper are as follows: 1. This paper briefly introduces the development and current situation of long-span PC continuous rigid frame bridge at home and abroad. The spatial finite element model of Shandian River Bridge is established by using Midas-Civil finite element calculation software. The causes of the deflection are analyzed from the factors of shrinkage and creep of concrete, loss of prestress, cracking, overweight, closure sequence and so on. Thus, we can get the understanding of the influence degree of the main beam deflection. 3. 3. According to the "zero moment method of dead load" extended from the thought of load balance, the comparison between Shandian River Bridge and two other similar three span continuous rigid frame bridges is made. Through the self-weight moment and the ratio of prestressing moment in the maximum cantilever stage of the main girder of each bridge, The influence of unbalanced bending moment on the long-term deflection of the main beam is obtained. 4. From the point of view of reducing the proportion of dead load in long-span PC continuous rigid frame bridge, the characteristics of high strength lightweight concrete are lighter than ordinary concrete, and the shrinkage and creep of high strength lightweight concrete are larger than that of ordinary concrete. The reasonable arrangement range of high strength lightweight concrete on the main beam is determined, and the influence of different arrangement range of high strength lightweight concrete on the stress and internal force of the key section of the main beam is studied.
【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】：U445.71;U448.23
本文编号：2301622
[Abstract]:With the development of engineering technology, more and more long-span continuous rigid frame bridges are widely used in bridge projects in China and the world, but due to some reasons in the construction process and operation period, Many long-span continuous rigid frame bridges have been caused various diseases, among which the most typical is the deflection of the main beam and the resulting cracking, which seriously affects the applicability, safety, durability and service life of the bridge. Although there are a lot of research results on the causes of bridge deflection, there is still a lack of deeper understanding, so it is necessary to do further research on this aspect. The main contents of this paper are as follows: 1. This paper briefly introduces the development and current situation of long-span PC continuous rigid frame bridge at home and abroad. The spatial finite element model of Shandian River Bridge is established by using Midas-Civil finite element calculation software. The causes of the deflection are analyzed from the factors of shrinkage and creep of concrete, loss of prestress, cracking, overweight, closure sequence and so on. Thus, we can get the understanding of the influence degree of the main beam deflection. 3. 3. According to the "zero moment method of dead load" extended from the thought of load balance, the comparison between Shandian River Bridge and two other similar three span continuous rigid frame bridges is made. Through the self-weight moment and the ratio of prestressing moment in the maximum cantilever stage of the main girder of each bridge, The influence of unbalanced bending moment on the long-term deflection of the main beam is obtained. 4. From the point of view of reducing the proportion of dead load in long-span PC continuous rigid frame bridge, the characteristics of high strength lightweight concrete are lighter than ordinary concrete, and the shrinkage and creep of high strength lightweight concrete are larger than that of ordinary concrete. The reasonable arrangement range of high strength lightweight concrete on the main beam is determined, and the influence of different arrangement range of high strength lightweight concrete on the stress and internal force of the key section of the main beam is studied.
【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】：U445.71;U448.23
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