混凝土强度不均匀性对悬臂法施工的桥梁结构影响分析

发布时间：2018-01-09 20:18

本文关键词：混凝土强度不均匀性对悬臂法施工的桥梁结构影响分析　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着大跨径预应力混凝土桥梁的发展,因悬臂浇筑法具有结构整体性好、施工变形易控制和不受桥下地形限制或通航限制等优点而被广泛采用。在悬臂浇筑施工过程中,混凝土受到配合比和现场养护条件等因素的影响,不仅使得混凝土强度和弹性模量偏离原设计值,而且每个节段的混凝土强度和弹性模量也会出现差异,从而使得桥梁结构受力偏离原设计值。因此,研究各个节段混凝土强度和弹性模量的差异对桥梁结构的影响具有重要的理论意义和工程实用价值。本文以某新建铁路线上预应力混凝土T形刚构为工程背景,借助有限元计算软件,通过合理的参数假设,研究因混凝土强度和弹性模量差异对桥梁结构的影响。通过修改混凝土的弹性模量,研究弹性模量的变化对成桥阶段影响,并通过定性分析给出合理的弹性模量的取值范围;通过修改各个节段混凝土强度和弹性模量发展函数,研究在施工阶段对主梁挠度和悬臂根部、跨中和最大悬臂端应力的影响。研究结果表明,混凝土弹性模量的变化对成桥阶段的挠度影响较大。当混凝土的弹性模量是1.0~1.1倍的设计值时,挠度变化的离散性较小,变形能得到较好的控制。当混凝土弹性模量发生变化时,对主梁1/4跨至最大悬臂端挠度影响较大。当修改混凝土强度和弹性模量发展函数时,在施工阶段结构体系发生转变前,对应力无影响,而在结构体系发生转变后,混凝土弹性模量的变化导致挠度产生变化,从而使得悬臂根部、跨中和最大悬臂端应力发生变化,并且当混凝土强度大于设计值一个等级时,应力偏离设计值较小。
[Abstract]:With the development of long-span prestressed concrete bridge, the cantilever pouring method has good structural integrity. The construction deformation is easy to control and is not restricted by the terrain under the bridge or navigation restrictions and other advantages are widely used. In the cantilever pouring construction process concrete is affected by mix ratio and site maintenance conditions and other factors. Not only the strength and elastic modulus of concrete deviate from the original design value, but also the concrete strength and elastic modulus of each segment will be different, which makes the force of bridge structure deviate from the original design value. It is of great theoretical significance and practical value to study the influence of concrete strength and elastic modulus on the bridge structure. In this paper, the T-shaped rigid frame of prestressed concrete on a new railway line is taken as the engineering background. By means of finite element calculation software and reasonable parameter hypothesis, the influence of concrete strength and elastic modulus on bridge structure is studied, and the elastic modulus of concrete is modified. The influence of the change of elastic modulus on the bridge stage is studied, and the reasonable range of elastic modulus is given by qualitative analysis. By modifying the development function of strength and elastic modulus of each segment of concrete, the effect of the construction stage on the deflection of the main beam, the root of the cantilever and the stress at the span and the maximum end of the cantilever are studied. The variation of elastic modulus of concrete has a great influence on the deflection of the bridge stage. When the elastic modulus of concrete is 1.0 ~ 1.1 times of the design value, the dispersion of the deflection change is smaller. The deformation can be controlled well. When the elastic modulus of concrete changes, the deflection of the 1/4 span to the maximum cantilever end of the main beam is greatly affected. When the development function of the strength and elastic modulus of concrete is modified. There is no effect on the stress before the structural system transition in the construction stage, but the change of the elastic modulus of concrete leads to the change of deflection after the transformation of the structure system, thus making the cantilever root. The stress changes at the end of the span and the maximum cantilever, and when the strength of concrete is larger than the design value, the stress deviation from the design value is smaller.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.466;U441

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