平头塔式起重机风荷载设计系数研究

发布时间：2018-05-22 19:53

本文选题：平头塔式起重机 + 风荷载　；参考：《华南理工大学》2015年硕士论文

【摘要】：塔式起重机是目前建筑工地使用的最为广泛的施工起重机械,随着现代建筑技术的不断发展,塔式起重机的发展也朝着工作高度更高、臂架长度更长的方向发展。对于高耸结构的塔式起重机而言,风载荷对其结构的影响也是不容忽视。目前塔式起重机的设计还是遵循着国家标准GB/T13752-1992《塔式起重机设计规范》进行的,该标准中对于风载荷对塔机的影响仅从风力系数、挡风折减系数、风压、迎风面积、截面充实率等几个变量进行描述,其中主要对于风载荷误差影响最大结构风荷载系数C已经远远不能满足现代塔机结构形式不断更新的要求,《塔式起重机设计规范》在塔机技术发展迅速的今天明显有着滞后性。本文针对QTP125平头塔式起重机为研究实例,通过分析其主要结构特点,整理出平头塔机常用的杆件类型,利用计算流体力学原理及有限元法,借助ANSYS CFX软件,主要研究塔机杆件结构在风环境下的稳态响应,稳态模拟通过标准的雷诺应力模型(SST)进行,计算塔机各部件在不同的结构形式、工况下,风荷载与结构风荷载系数C。本文首先对平头塔式起重机常用杆件进行分类整理,整理出圆管、圆角方管、槽钢三种主要型材类型及对应截面规格共20种,并对各截面规格的杆件的在不同长细比(长径比)下的风阻力特性、风荷载系数值进行模拟计算研究。并根据实际环境状态将风速分为极限工作风速和极限非工作风速进行模拟分析。分析结果显示,圆管的风荷载系数在所研究的范围内随着直径的增加而减小,圆角方管则基本不变,同时发现在规范中没有详细列明的槽钢则明显比规范参考值大幅增加,其主因是当槽钢正面受风时,正面区域形成较大的低风速区并对结构形成较大的风压。上述研究结果为后续的研究提供共重要的参考,也为现行的设计规范提供了很好的补充。最后,通过利用本文获得的风荷载系数值对QTP125平头塔式起重机进行结构抗风性能校核,通过计算结果与原设计进行对比发现,回转阻力矩值较原设计提高14.7%,整机结构风荷载值较原设计提高64%,并发现原设计塔身标准节L68B1结构存在明显的抗风性能缺陷,并进行结构优化设计。
[Abstract]:Tower crane is the most widely used construction crane on construction site. With the development of modern building technology, tower crane is developing towards higher working height and longer arm length. For towering tower crane, the influence of wind load on its structure can not be ignored. At present, the design of tower crane is carried out in accordance with the national standard GB/T13752-1992 "Design Code for Tower Crane". In this standard, the influence of wind load on tower crane is only from wind coefficient, windshield reduction coefficient, wind pressure, upwind area. Several variables, such as cross-section fullness ratio, are described. The maximum wind load coefficient C, which mainly affects the wind load error, is far from being able to meet the requirement of updating the structure form of modern tower crane. The Design Code for Tower Crane is obviously lagging behind with the rapid development of tower crane technology today. In this paper, by analyzing the main structural characteristics of QTP125 flat tower crane, the commonly used rod types of flat head tower crane are sorted out, and the principle of computational fluid mechanics and finite element method are used, with the help of ANSYS CFX software. The steady-state response of tower crane rod structure under wind environment is studied. The steady state simulation is carried out through the standard Reynolds stress model (SST). The wind load and wind load coefficient C of the tower crane are calculated under different structural forms and working conditions. In this paper, the common members of flat head tower crane are sorted out, and 20 kinds of circular pipe, round corner square tube and channel steel are arranged. The wind resistance characteristics and wind load coefficient of different aspect ratio (aspect / diameter ratio) of the members with different cross-section specifications are simulated and calculated. According to the actual environment condition, the wind speed is divided into the limit working wind speed and the limit non-working wind speed to carry on the simulation analysis. The analysis results show that the wind load coefficient of circular pipe decreases with the increase of diameter in the studied range, while the circular square tube is basically unchanged. At the same time, it is found that the channel steel which is not specified in detail in the code increases significantly compared with the reference value of the code. The main reason is that when the channel face is exposed to wind, the front area forms a large low wind speed zone and a large wind pressure on the structure. These results provide important reference for further research, and also provide a good supplement to the current design specifications. Finally, by using the wind load coefficient obtained in this paper to check the structural wind resistance of QTP125 flat head tower crane, the results are compared with the original design. Compared with the original design, the torque value of rotary resistance is increased by 14.7 and the wind load value of the whole machine structure is increased by 64. It is found that the original L68B1 structure of the tower body standard section has obvious anti-wind performance defects, and the structural optimization design is carried out.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH213.3

【相似文献】