摘要
桁架受压弦杆受到相邻杆件的约束,其计算长度不能直接按两端铰接或两端固定杆件来取值。基于合理的假定,考虑相邻节间弦杆内力比对矩形钢管混凝土桁架受压弦杆计算长度的影响,推导出矩形钢管混凝土桁架受压弦杆屈曲的特征方程,给出相应的计算长度系数,并对不同截面的矩形钢管桁架受压弦杆进行了有限元计算。结果表明,采用计算长度系数的计算结果与有限元计算结果吻合较好,相邻弦杆的内力比对受压弦杆的计算长度影响明显,考虑相邻弦杆的内力比对计算长度的影响后,受压弦杆的计算长度系数有所减小。最后给出了便于工程应用的受压弦杆计算长度系数简化计算公式。
The calculation for the effective length of the compress ive chord members in the truss can not be considered as hinged joints or fixed i n each member end,because the compressive chord members of the truss are restra ined by the contiguous ones.Based on the reasonable hypothesis,the eigenvalue equa tions of the compressive chord members in concrete-filled rectangular steel truss（CFRT） are derived by considering the effect of the internal force ratio of the contiguous chord members,whose coefficients of the effective length of compressive chord members are elicited.The finite element calculations of the different sections of the compressive chord members in CFRT were carried out.The calculating effective length of compressive chord members in CFRT by the equations proposed agrees well with the finite element calculating ones.The re sults show that the effect of the internal force ratio of the contiguous chord membe rs to the effective length of compressive chord is prominent.As considering the effect of the internal force ratio of the contiguous chord members,the coeffic ients of the effcetive length of compressive chord members are decreased.The simplified formula of the coefficients of the effective length of compressive cho rd members are given,which can be conveniently applied in projects.
出处
《钢结构》
2009年第4期23-25,29,共4页
Steel Construction
基金
国家重大基础研究前期研究专项资助项目(2004CA03300)
国家自然科学基金(50878087)资助项目。
关键词
矩形钢管混凝土
桁架
受压弦杆
计算长度
稳定性
有限元
concrete-filled rectangular steel tubular
truss
compressive chord member
effective len gth
stability
finite element
