【作者】 王浩科；

【导师】 戴国欣；

【作者基本信息】 重庆大学 ， 结构工程， 2004， 硕士

【摘要】 中国工程建设标准化协会2002年制定了《门式刚架轻型房屋钢结构技术规程》(CECS102:2002)。该《规程》在对门式刚架楔形柱进行稳定验算时,对门式刚架最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,这样就使得设计工作大大简化。然而,实验及相关分析表明,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。柱脚实际存在的这种转动约束必然会增强楔形柱的稳定承载能力,那么这种约束究竟能在多大程度上增强楔形柱的稳定性能(实际上是门式刚架的整体稳定性能)?如何在设计中利用这一有利条件?针对上述问题,本文对比了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,引入了考虑不同的柱脚构造在柱子轴力、弯矩均随加载过程变化的变刚度柱脚约束力学模型,并采用考虑二阶非线性的有限元方法对门式刚架的整体稳定计算编制了程序,用计算机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。然后与不考虑柱脚约束的计算结果进行对比,研究了简易柱脚实际存在的抗转动约束能力能在多大程度上增强门式刚架的稳定承载力。发现柱脚配置4枚锚栓的柱脚具有很强的抗转动约束能力,该约束能力显著的提高门式刚架的平面内稳定承载力,可以在工程设计中考虑这种有利作用,更进一步节约材料,提高经济指标,并提出了具体的而且较为简单的措施。而柱脚仅配置2枚锚栓时,柱脚的抗转动约束能力表现的不太明显,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,不能过高的提高刚架的稳定承载力。但在保证一定的柱脚构造要求后,就可以较为安全使用《规程》的计算值。更多还原

【Abstract】 The Standardization Institute of Chinese Construction enacted Technical specification for steel structure of light-weight buildings with gabled frames (CECS102:2002) in 2002. In the Specification, two kinds of column bases which have one plate and two or four anchor bolts are the most popular in portal frames and are considered as pinned bases when the stability for wedge-shaped column of portal frame is checked. It simplifies the design greatly. However, it has been proved that the two kinds of column bases (especially the base with four anchor bolts) actually have remarkable ability of rotational restrict with the deduction of theory and experiments. The rotational restrict of column base certainly improved the stability of the frame, but how much can the restrict increase the stability? And how to use the advantage in design?On the above-mentioned issue, it is compared in the this paper that the research was made before on the rotational restricted stiffness of column base. With experimental information and relational analysis, it is introduced that the variational-stiffness column base modeling which is relative with axial force and moment. And the codes are made with second-order non-linear finite element methods for analyzing overall stability of portal frame. A lot of cases are computed with computer for stability of one-bay portal frame loaded by typical loads. After that, it is compared with the results of non-restrict column base. It is concluded that the column base with 4 anchor bolts has considerable anti-rotational ability, and the overall stability in plane of portal frame is remarkably strengthened by the ability. This advantage could be used in design, save lots of materials. And simple measures are introduced. And the anti-rotational ability of column base with 2 anchor bolts is neglectable. 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 when column base is consisted of 2 anchor bolts. But when the structure of column base is ensured, the Specification’s stable capacity could be used safely.更多还原