实测缺陷对扣件式钢管脚手架结构极限承载力的影响分析

发布时间：2018-07-28 19:45

【摘要】：脚手架作为一种临时结构，，它的运用已经成为建筑行业不可缺少的一个部分。而在脚手架的众多种类中，扣件式钢管脚手架因具有造价低廉、搭设简单、对场地要求低、承载力高等优势而处于主导地位。扣件式钢管脚手架是一种杆系结构，为缺陷敏感结构体系，而结构所用的钢管杆件是长期重复使用的，存在壁厚磨损、初弯曲等累积效应。虽然规范中有规定，但现实管材重复使用后的缺陷实测及统计分析很少有报道，尚未形成统一的缺陷分析理论与方法。为确保扣件式钢管脚手架结构使用安全，开展实测缺陷对结构性能的影响研究具有重要的理论意义和工程应用价值。本文基于故障树分析法，建立扣件式脚手架的安全事故的故障树图，分析引起事故的各个底事件的结构重要度，为预防事故提供一定的参考价值。根据在某省注册登记的建筑施工企业资质等级情况，结合某市实际情况，按随机分层抽样方法，对18个不同资质等级企业的扣件式脚手架工程所用管材，在现场随机抽测尺寸48mm×3.5mm和48.3mm×3.6mm、长度为6m和3m钢管的壁厚、外径、初始弯曲等原始数据共2340个，对数据样本进行统计分析，运用改进型格拉布斯法对数据进行检测，剔除异常值，建立了初始缺陷随机分布规律和概率函数参数的统计信息。在此基础上，基于有限元理论知识，考虑节点的半刚性，借助ANSYS软件，建立扣件式钢管脚手架的有限元模型。以实测初始缺陷为基础，运用一致模态法，以不同的荷载工况（满跨均布荷载、满跨不对称荷载）、不同扣件扭紧力矩（30N·m、40N·m、50N·m）、不同的缺陷（规范限值3L/1000、实测L/220）等作为参数，通过分析对结构极限承载力的影响程度，获得特征点的荷载位移曲线，为脚手架的安全使用提供理论依据。
[Abstract]:Scaffolding as a temporary structure, its application has become an indispensable part of the construction industry. Among the many kinds of scaffolding, fastener steel tube scaffolding is dominant because of its advantages of low cost, simple installation, low demand for the site and high bearing capacity. The steel tube scaffolding with fastener is a kind of rod structure, which is a defect-sensitive structure system, and the steel tube member used in the structure is reused for a long time, which has the cumulative effects of wall thickness wear and initial bending. Although there are some regulations in the specification, there are few reports on the defect measurement and statistical analysis after repeated use of practical pipes, and a unified theory and method of defect analysis have not yet been formed. In order to ensure the safety of fastener steel tube scaffolding structure, it is of great theoretical significance and engineering application value to study the effect of the measured defects on the structure performance. Based on the fault tree analysis method, the fault tree diagram of the safety accidents of fastener scaffolding is established, and the structural importance of each bottom event caused by the accident is analyzed, which provides a certain reference value for the prevention of accidents. According to the qualification grade of construction enterprises registered in a certain province and the actual situation of a certain city, according to the random stratified sampling method, the pipes used in fastener scaffolding engineering of 18 enterprises with different qualification grades are studied. The size of 48mm 脳 3.5mm and 48.3mm 脳 3.6mm is measured at random in the field, and the wall thickness, outer diameter and initial bending of steel pipe of 6m and 3m are measured at random. The data samples are statistically analyzed, and the data are detected by improved Grubbs method, and the abnormal values are eliminated. The random distribution of initial defects and the statistical information of the parameters of probability function are established. Based on the knowledge of finite element theory and considering the semi-rigidity of joints, the finite element model of fastener steel tube scaffolding is established by means of ANSYS software. Based on the measured initial defect, the uniform mode method is used to take different load conditions (full span uniform load, full span asymmetric load) and different fastener torsion moment (30N mNs 40N mNM / 50N m),) as parameters, such as different defects (code limit value 3L / 1000, measured L / 220), and so on. The load-displacement curve of the characteristic point is obtained by analyzing the influence degree on the ultimate bearing capacity of the structure, which provides the theoretical basis for the safe use of the scaffold.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU731.2

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