(1 中国建筑设计研究院 北京 100044)
(2 清华大学 北京 100084)
【提要】 国家体育场屋盖肩部次结构扭曲构件以受弯为主，构件壁厚很薄，板件容易发生局部屈曲。对扭曲构件受力机理进行了深入的研究，提出设置内部加劲肋的方式提高箱形扭曲构件的抗弯刚度，减小板件的面外变形。通过调整加劲肋间距，使扭曲构件与分段折线箱形构件的强度与刚度相等。在确定加劲肋形状时，综合考虑焊接操作空间、节约材料等因素。设计过程中除进行大量有限元计算分析外，还进行了缩尺模型试验，验证设计方法的可靠性。
【关键词】 扭曲构件 局部屈曲 受力机理 有效宽厚比 加劲肋 承载力
Design and Research of Twistcurved Boxsections for Roof Secondary Members of  the National Stadium/Fan Zhong1，Peng Yi1，Wang Zhe1，Qian Jiaru 2，Zhao Zuozhou2(1 China Architecture Design & Research Group,Beijing 100044,China；2 Tsinghua University,Beijing 100084,China)
Abstract:The twistcurved boxsections for the faade secondary members of the National Stadium are mainly subjected to bending moment,since the thickness of the member walls is very thin and local buckling of the plates occurs easily under compression.Based on the study of the behavior of the twistcurved member under bending moment,a design method for twistcurved members is presented.Using inner stiffeners can increase the bending stiffness and reduce the outward deformation of the plates effectively.The strength and stiffness of the twistcurved element can be equal to that of the segmental straightline box section by adjusting the distance between the inner stiffeners.In addition,the welding space and material cost should be considered when determining the shape of stiffeners.During the design procedure,except lager amount of finite element analysis,four scaledspecimen experiments are made to prove the reliability of the design method for twistcurved member.
Keywords:twistcurved boxsection；local buckling；working principle；effective width；stiffener；bearing capacity