碗扣式脚手架的传力规律研究及缺陷分析

发布时间：2018-06-24 04:59

本文选题：碗扣式脚手架 + 试验　；参考：《安徽建筑大学》2016年硕士论文

【摘要】：随着中国经济在最近几年的飞速增长,各种各样的立交桥、地铁及建筑也得到了很好的建设,碗扣式脚手架在这些建筑中得到了广泛的使用。与此同时,近年来,施工现场常见的支架受力复杂、搭设不合理、构件的初始缺陷及荷载偏心等不利因素,使得脚手架事故时有发生,导致人员死亡及经济财产损失。因此对于支架缺陷的分析研究、支架整个传力过程和整个体系的关键受力点的研究以及有关支架有效完整的监控方法是被大量的使用人员所迫切需要的。本文以安徽某地铁项目为基础,在实验室对碗扣式模板支架承载力进行了相关试验,探究了碗扣式钢管支架在承受竖向荷载时,支架中立杆和横杆应力变化、支架体系从上到下的传递方式和相关规律、节点连接及受力性质,获得了支架受力最大的杆件,为以后设计及施工搭设提供参考价值。另外,本文还通过有限元分析软件ANSYS针对试验支架建立合理的有限元模型,本次模型节点采用铰接方式,模型按1:1比例建模,主要进行了线性及非线性屈曲分析,然后将试验分析结果与有限元ANSYS分析结果进行了对比,从而更好的印证了支架杆件传递规律及节点连接受力性质等结论。同时,本文对安徽某轨道交通车站主体结构地下一层顶板以及侧墙混凝土浇筑过程中的脚手架部分杆件内力进行实时监测,并运用ANSYS建立实际工程模型,该模型主要承受顶板混凝土浇筑时的竖向荷载作用以及在侧墙混凝土浇筑时的水平荷载作用。在建立顶板混凝土浇筑时的竖向荷载作用的模型时,主要分析了支撑体系的杆件及节点的受力情况,找到结构的薄弱点,并与上面脚手架试验及ANSYS模拟分析结果对比,从而进一步印证了支架杆件传递规律及节点连接受力性质等结论;在建立侧墙混凝土浇筑的水平荷载作用的模型时,主要研究分析了其混凝土浇筑速度、水平剪刀撑、垂直剪刀撑及模型采用刚接和铰接等因素对支架承载力的影响情况。最后以上面4×4跨碗扣式满堂脚手架支撑体系加载试验以及安徽某轨道交通车站施工现场使用的钢管脚手架为基础,通过检查了试验室以及施工现场脚手架的相关规格及搭设状况,发现脚手架存在外径不达标、壁厚不足、钢管弯曲及搭设不合格等问题,对试验室中碗扣式满堂支撑体系在理想情况下以及钢管缺陷、施工不合理及荷载偏心等缺陷情况下进行了杆件的强度、刚度和稳定性的计算,通过对比计算得出:支架的施工不合理、钢管缺陷及荷载偏心等缺陷对支架承载力有很大的不利影响。并针对这些缺陷或不足提出了选取材料及施工搭设过程的安全控制建议以及支撑体系计算优化建议。
[Abstract]:With the rapid growth of China's economy in recent years, various overpasses, subways and buildings have been well built, and bowl-buttoned scaffolding has been widely used in these buildings. At the same time, in recent years, the common unfavorable factors, such as complex force, unreasonable erection, initial defects and eccentric load, make scaffolding accidents occur frequently, resulting in death of personnel and loss of economic property. Therefore, for the analysis and research of the scaffold defects, the research of the whole load transfer process and the key force points of the whole system, and the effective and complete monitoring method of the support are urgently needed by a large number of users. Based on a subway project in Anhui province, the bearing capacity of bowl-buttoned formwork support was tested in laboratory, and the stress changes of stand bar and crossbar of bowl buttoned steel pipe support under vertical load were investigated. From top to bottom, the transfer mode and related law of support system, the connection of joints and the properties of bearing force are obtained, which provides the reference value for the design and construction of the braces with the greatest force. In addition, the finite element analysis software ANSYS is used to establish a reasonable finite element model for the test support. The joint of the model is hinged and the model is modeled according to the 1:1 scale. The linear and nonlinear buckling analysis is mainly carried out. Then, the experimental results are compared with the finite element ANSYS analysis results, which better confirm the support member transfer law and joint connection force properties and other conclusions. At the same time, this paper monitors the internal force of the scaffold in the concrete pouring process of the underground first floor and side wall of the main structure of a rail transit station in Anhui Province, and establishes the actual engineering model by using ANSYS. The model mainly bears the vertical load when the roof concrete is pouring and the horizontal load when the side wall concrete is pouring. In establishing the vertical load model of roof concrete, the stress of the members and joints of the bracing system is analyzed, the weakness of the structure is found, and the results are compared with the results of the upper scaffold test and ANSYS simulation analysis. In order to further confirm the support member transfer law and joint connection mechanical properties and other conclusions, in the establishment of lateral wall concrete pouring model of horizontal load, the main analysis of its concrete pouring speed, horizontal scissors brace, The influence of vertical shear brace and rigid joint and hinge joint on the bearing capacity of the support. Finally, on the basis of the loading test of the above 4 脳 4 span bowl-fastened scaffold support system and the steel tube scaffolding used in the construction site of a rail transit station in Anhui Province, By checking the relevant specifications and erection conditions of the scaffolding in the laboratory and the construction site, it is found that the scaffold has some problems such as the outside diameter is not up to the standard, the wall thickness is insufficient, the steel tube is bent and the erection is not up to standard, and so on. In this paper, the strength, stiffness and stability of the bar are calculated under ideal conditions and defects such as steel pipe defects, unreasonable construction and load eccentricity. Through comparison and calculation, it is concluded that the construction of the support is unreasonable, the defects of steel pipe and load eccentricity have a great adverse effect on the bearing capacity of the support. Aiming at these defects, the paper puts forward the safety control suggestion of selecting material and construction erection process and the suggestion of calculation and optimization of support system.
【学位授予单位】：安徽建筑大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU731.2;TU311

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