【作者】 陈正娟；

【导师】 戴国欣；

【作者基本信息】 重庆大学 ， 结构工程， 2007， 硕士

【摘要】 在依照中国工程建设标准化协会于2002年颁布的《门式刚架轻型房屋钢结构技术规程》(CECS102:2002)对门式刚架楔形柱进行稳定验算时,通常将经常采用的两种简易柱脚形式(1块底板加2或4枚锚栓的柱脚)一概视为铰接,这样就使设计工作大大简化。然而,实验及相关分析[55]表明,这两种柱脚形式(特别是4枚锚栓的简易柱脚)实际上具有相当程度的抗转动能力。文献[55]就柱脚实际存在的这种转动约束能在多大程度上增强楔形柱的稳定承载能力做了细致的研究,然而在研究过程中未能计入初始缺陷对该承载力提高的影响。针对上述问题,本文主要针对初始缺陷中的H型钢残余应力,对比前人所做的关于柱脚转动约束刚度的研究,在借鉴实验资料及有关分析的基础上,引入了三种焊接残余应力的计算模型,并对在文献[55]中采用的考虑了二阶非线性有限元方法计算门式刚架整体稳定的计算机程序进行了修改,对单跨门式刚架在有代表性的荷载形式作用下进行了大量的计算。然后与不考虑残余应力的计算结果[55]进行对比,研究了残余应力对单考虑柱脚转动约束的门式刚架稳定承载力增强的影响。发现焊接残余应力对柱脚配置4枚锚栓的抗转动约束能力的影响较弱,证明可以在工程设计中适当考虑该有利作用,进一步节约材料,提高经济指标,并提出了具体的且较为简单的措施。而柱脚仅配置2枚锚栓时,柱脚的抗转动约束能力在计入焊接残余应力影响后降幅较大,而且当锚栓直径、底板厚度较小时,刚架的实际承载能力甚至低于《规程》的计算值,因此,建议当柱脚仅配置2枚锚栓时,不宜提高刚架的稳定承载力,在保证一定的柱脚构造要求后,才可以较为安全的使用《规程》的计算值。更多还原

【Abstract】 When testing the in-plane stability of portal frame according to Technical specification for steel structure of light-weighted buildings with gabled frames (CECS102: 2002) enacted by the Standardization Institute of Chinese Construction in 2002, it usually takes the two staple simplified column feet as hinged column feet, which makes the designing work rather easily. However, it has been proved that the two kinds of column feet (especially the foot with four anchor bolts) actually have remarkable ability of rotational restrict with the deduction of theory and experiments. In referenced essay [55], the improved the stability of the frame is carefully studied, but the was not concerned.Aiming at the above-mentioned issues, considering residual stress in this paper, compared with the researches on the rotational restricted stiffness of column feet made before, with experimental information and relational analysis, three sealed residual stress modeling are introduced. Codes are modified which were made in referenced essay [55] based on second-order non-linear finite element methods and for analyzing overall stability of portal frame. Three typical modeling of residual stresses are introduced to compute stability of one-bay portal frame loaded by typical loads with computer. After that, it is compared with the results without the affection of partial residual stresses, studies the affection due to sealed residual stresses act on one-bay portal frame based on column feet by rotational restriction. It is concluded that sealed residual stresses has a faint impact on the anti-rotational ability of column feet with 4 anchor bolts, and the overall influences slightly decrease the in-plane stability of portal frame based on column foot by rotational restriction without the residual stresses. It is proved that this advantage could be used in design, saving lots of materials and simple measures are introduced as well. On the other hand, the infection on anti-rotational ability of column base with 2 anchor bolts is un-negligible. Moreover, the actual stability is less than Specification’s when the diameter of anchor bolts and the thickness of column base plate are too small. So it is suggested that no improving the overall stable capacity could be introduced when column base is consisted of 2 anchor bolts. Only when the structure of column base is ensured, could the Specification’s stable capacity be used safely.更多还原