【作者】 宋延勇；

【导师】 李元齐；

【作者基本信息】 同济大学 ， 结构工程， 2008， 硕士

【摘要】 材料科学的发展及加工技术的进步使得冷弯薄壁型钢结构在世界范围内得以广泛应用。冷弯薄壁型钢构件朝着高强、超薄方向发展,壁厚2mm以下的冷弯薄壁型钢构件已大量用于工程实际。而我国现行《冷弯薄壁型钢结构技术规范》仅适用于壁厚2mm～6mm的承重构件,壁厚2mm以下的冷弯薄壁型钢构件的设计与计算在我国尚无技术标准可依。本文以“低层冷弯薄壁型钢建筑试验研究”课题为依托,结合国内外现有研究成果,对壁厚2mm以下Q235钢材冷弯薄壁型钢偏压构件及自攻螺钉连接的承载力性能进行了系统的理论与试验研究。本文首先对66根壁厚2mm以下冷弯薄壁型钢偏压构件(包括开口C形及组合I形两种截面形式)进行了试验研究,并采用大型通用有限元软件ANSYS对其进行了数值计算与分析。基于试验研究及数值分析,本文对中国,澳大利亚(新西兰)和北美冷弯薄壁型钢结构设计规范偏压构件承载力设计计算方法进行了对比分析;对我国现行《冷弯薄壁型钢结构技术规范》相关设计计算方法对壁厚2mm以下的冷弯薄壁型钢偏压构件的适用性进行了验证;并提出了组合I型截面偏压构件的设计计算方法。结合试验研究结果,本文还对我国现行《冷弯薄壁型钢结构技术规范》的开口C形截面的冷弯薄壁型钢偏压构件设计计算方法进行了可靠度分析。其次,本文还进行了75个自攻螺钉连接的剪切试验研究,基于试验研究结果,探讨了螺钉数目、螺钉排列方式、螺钉间距及端距、板件材料等因素对连接性能的影响。本文研究结果表明:自攻螺钉连接中存在“群体效应”,我国现行《冷弯薄壁型钢结构技术规范》中相关设计计算方法忽略群体效应,对含多颗螺钉的自攻螺钉连接偏于不安全。基于试验及理论研究,结合国内外现有研究成果,本文提出了白攻螺钉连接抗剪承载力的设计计算方法。本文建议的设计计算方法考虑了自攻螺钉连接中存在“群体效应”,引入了螺钉间距修正系数,其理论计算结果与试件试验实测承载力比较吻合,具有一定的合理性。更多还原

【Abstract】 The use of cold-formed thin-walled steel structures has increased rapidly in recent years due to significant development of material science and improvements of manufacturing technologies. An important tendency of cold-formed steel structure is the application of more slender structure members and elements with higher strength. At present, cold-formed steel members with thickness less than 2mm have been widely used into practice projects. However, Chinese current national standard Technical code of cold-formed thin-walled steel structures can only be applied to calculate and design the cold-formed thin-walled steel members with thickness between 2mm and 6mm. The calculation and design methods for cold-formed thin-walled steel members less than 2mm thick have been not included in and there are no standards for cold-formed thin-walled steel members less than 2mm thick design and calculation in China yet. Cold-formed steel eccentrically-compressed columns less than 2mm thick and self-drilling screw connections are systemically researched in this thesis.Firstly, a series of experimental research on cold-formed eccentrically-compressed columns were carried out. 66 cold-formed steel members, including lipped-channels and combined I sections, were tested in this experimental research. Besides this, the widely used finite element software, ANSYS, was also employed for analysis. Based on experimental investigation and numerical analysis, calculation methods for the strength of eccentrically-compressed columns present in the codes or specifications of China, Australia/New Zealand and North American were compared and investigated. The research result shows that the calculation formulas of Chinese current national standard Technical code of cold-formed thin-walled steel structures can be used to calculate the strength of cold-formed steel eccentrically-compressed columns with thickness less than 2mm. A simplified calculation method for combined I section eccentrically-compressed columns was also proposed. Besides these, reliability analysis was also done to further verify the applicability of the channel calculation formulas of Chinese code.Secondly, a series of shear tests have also been conducted on self-drilling screw connections. The factors influencing the shear behavior of the connections, the number of screws, screw patterns, screw spacing, edge distance, sheet material included, were investigated. The findings of the research demonstrated the existence of "Group Effect" in the connections including more than one screw, which means that the assumption that the connection strength for a multiple screw connection is proportional to the number of screws in the connection, as the calculation method in Chinese current national standard Technical code of cold-formed thin-walled steel structures have based on, would result in an unconservative estimate for the shear capability of connections including more than one screw. Based on experimental study and existing research fruits, a modified calculation formula has been proposed in this paper. The shear strength of the specimens calculated via the modified calculation formula, in which both "Group Effect" and screw spacing influence were took into account, agreed well with the experimental result and the rationality of the modified calculation formula was verified thus.更多还原