大面积混凝土厂房地坪环境温度效应研究

发布时间：2018-04-03 20:52

本文选题：大面积混凝土　切入点：有限元　出处：《沈阳建筑大学》2013年硕士论文

【摘要】：随着制造业的飞速发展,厂房的建设规模在不断地扩大,对于厂房地坪这种大面积混凝土的研究重点之一就是如何处理环境温度和收缩作用引起的结构开裂,特别是在北方寒冷地区,结构投入使用前施工周期需要跨过一个采暖期的工程这一点非常重要。本文以实际工程为背景,通过理论和有限元软件的分析计算,研究了大面积混凝土地坪的环境温度效应。从已有的理论和工程实际出发,本文在研究结构环境温度效应过程中主要考虑了环境温度变化、收缩和徐变等因素,确定了混凝土地坪的最不利温差,最不利温差包括环境温度的整体变化和混凝土的收缩当量温差,并用理论公式和有限元软件ABAQUS分别计算出了在最不利温差下的温度应力,结果差异不大。按照工程实际建立有限元模型进行线弹性分析,分析中假定混凝土是连续均质材料,地基不发生不均匀沉降,混凝土的弹性模量不随时间变化。混凝土板的约束主要来自板与下部地基的摩擦作用。通过有限元分析得出的结果是：混凝土地坪板最大应力出现在板的中间部位,从板中到板端应力逐渐减小,这与实际工程中假缝切割后的混凝土板中间部位开裂相符合,进而可以说明施工过程中假缝的切割尺寸不合理,切割后的混凝土板内的温度应力仍大于混凝土的抗拉强度,造成混凝土开裂。之后取不同尺寸的混凝土板在相同的约束条件和荷载下分别计算其内部温度应力,通过比较最终得出比较合理的假缝切割尺寸为6m×4.5m。最后通过改变混凝土板的长度、厚度、混凝土强度等因素,分析这些因素对混凝土板的温度应力影响规律。
[Abstract]:With the rapid development of the manufacturing industry, the construction scale of the factory building is constantly expanding. One of the key points of the research on the large area concrete such as the workshop floor is how to deal with the structural cracking caused by the environmental temperature and shrinkage.Especially in the cold area of the north, it is very important that the construction cycle should cross a heating period before the structure is put into use.In this paper, the environmental temperature effect of large area concrete floor is studied by theoretical analysis and finite element software based on actual engineering.Based on the existing theory and engineering practice, this paper mainly considers the environmental temperature change, shrinkage and creep, and determines the most unfavorable temperature difference of concrete floor in the process of studying the structural environmental temperature effect.The most unfavorable temperature difference includes the whole change of ambient temperature and the shrinkage equivalent temperature difference of concrete. The temperature stress under the most unfavorable temperature difference is calculated by theoretical formula and finite element software ABAQUS.According to the engineering practice, the finite element model is established for linear elastic analysis. In the analysis, it is assumed that the concrete is a continuous homogeneous material, the foundation does not have uneven settlement, and the elastic modulus of concrete does not change with time.The constraint of concrete slabs mainly comes from the friction between the slabs and the subsoil.The results obtained by finite element analysis are as follows: the maximum stress of concrete floor slab appears in the middle part of the slab, and the stress decreases gradually from the middle of the slab to the end of the slab, which is consistent with the cracking in the middle part of the concrete slab after cutting the false joint in the actual engineering.It can be concluded that the cutting size of the artificial joint is unreasonable and the temperature stress in the cut concrete slab is still larger than the tensile strength of the concrete, which leads to the cracking of the concrete.Then the internal temperature stresses of concrete slabs with different sizes are calculated under the same constraint conditions and loads. The reasonable cutting size of false joint is 6m 脳 4.5m.Finally, by changing the length, thickness and strength of concrete slab, the influence of these factors on the temperature stress of concrete slab is analyzed.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU755

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