碗扣式模板支架体系稳定承载力分析

发布时间：2018-09-07 12:42

【摘要】：碗扣式模板支架体系是工程施工中的一种临时结构,具有复杂性、变化性、随机性和难控性等特点。近年来,与模板支架坍塌的相关安全事故在施工项目安全事故发生总频次中占有很大比例。因此,如何保证碗扣式模板支架体系的整体稳定性已成为目前重点关注的课题之一。本文在已有研究的基础上,利用有限元软件ANSYS建立碗扣式模板支架有限元模型,对模板支架整体稳定性及其影响影响因素进一步分析和探讨,主要得出以下几点结论:(1)将模板支架简化为有多个弹簧支座的多节间连续压杆的计算简图来计算其稳定承载力是合理的,考虑到剪刀撑、扫地杆高度和立杆伸出顶层水平杆长度、架体高度等因素对支架稳定承载力的影响,对该理论的计算公式进行修正。(2)连续压杆理论中的弹簧刚度k的取值取决于立杆与水平杆连接处的碗扣节点的结构特性和材料特性两个方面,偏于安全,取二者中的较小值;(3)建立支架半刚性有限元模型分析支架稳定承载力的影响因素,得出:支架承载力随着扫地杆高度和立杆伸出顶层水平杆长度的增大而减小;在架体较弱方向的节点施加假想水平力来模拟初始缺陷是合理的;减小步距更能提高支架的承载力,并且进一步提出了立杆计算长度修正系数;立杆底端支座脱空对支架承载力的影响程度:拐角立杆最大,边部立杆其次,中间最小。(4)通过15种工况的支架有限元模型分析了剪刀撑的斜杆配置率xa与支架稳定承载力crP之间的关系,当架体构架参数相同时,剪刀撑的作用是随着斜杆配置率和其搭设方式而变化的,只有当剪刀撑科学搭设时,支架稳定承载力才随着斜杆配置率的增大而增大。
[Abstract]:The bowl-button formwork support system is a kind of temporary structure in the engineering construction, which has the characteristics of complexity, variety, randomness and difficulty to control and so on. In recent years, the safety accidents related to the collapse of formwork support occupy a large proportion of the total frequency of safety accidents in construction projects. Therefore, how to ensure the overall stability of the bowl fastener has become one of the most important issues. On the basis of the existing research, the finite element model of the bowl-button formwork bracket is established by using the finite element software ANSYS, and the overall stability of the template bracket and its influencing factors are further analyzed and discussed. The main conclusions are as follows: (1) it is reasonable to simplify the template support to the calculation diagram of the continuous pressure bar with multiple spring supports to calculate its stable bearing capacity, considering the shear braces, The influence of the height of floor sweeping rod, the length of horizontal pole extending out of the top floor and the height of frame body on the stable bearing capacity of the support, The calculation formula of this theory is modified. (2) the value of spring stiffness k in the theory of continuous compression rod depends on the structural characteristics and material characteristics of the bowl-buckle joint at the connection between the vertical bar and the horizontal bar, and is more safety. (3) establishing semi-rigid finite element model to analyze the influence factors of the support stability bearing capacity. It is concluded that the support bearing capacity decreases with the increase of the height of the floor sweeping rod and the length of the horizontal bar extending out of the top floor of the vertical pole. It is reasonable to apply hypothetical horizontal force to simulate the initial defect at the node in the weaker direction of the frame, and to reduce the step distance can improve the bearing capacity of the support, and further put forward the calculation length correction coefficient of the vertical rod. The degree of influence on the bearing capacity of the support is as follows: the corner shaft is the biggest, the side shaft is the second, (4) through the finite element model of 15 kinds of working conditions, the relationship between xa and crP is analyzed. When the frame parameters are the same, The effect of shear-brace varies with the collocation rate of skew rod and its setting mode. Only when the shear-bracing is scientifically installed, the stable bearing capacity of the support increases with the increase of the collocation rate of the skew rod.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU731.2

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