蝶撑桁架梁跨中挠度的计算方法研究

STUDY ON THE DEFLECTION OF BUTTERFLY-SHAPED CLIPS TRUSS GIRDERS

鉴于蝶撑桁架梁的连接件和弦管之间采用半刚性连接,且桁架梁主要由其跨中挠度控制设计,因此该文在试验研究的基础上,针对此结构的跨中挠度计算方法进行了研究。通过借鉴钢-混凝土组合梁跨中挠度的分析方法,在考虑上下弦管之间错动位移的基础上,以桁架梁微段为受力单元,推导出均布荷载作用下简支蝶撑桁架梁由错动位移引起的附加曲率,继而利用共轭梁法求得桁架梁跨中挠度的计算公式,并将公式计算值和试验及有限元分析值进行了对比。结果表明:该计算公式计算效果理想,可为该类型桁架梁的研究及实际工程应用提供理论依据。

With regard to the semi-rigid connection between the clips and upper or lower chord tube, the design of the light-gauge-steel truss girders with butterfly-shaped clips is often controlled by the mid-span deflection. This paper focused on the calculation of the deflection at the mid-span based on experimental research. The method of calculating the mid-span deflection of concrete-steel composite beam was used in this study. Also, in order to consider the slip effect between the upper and lower chord tubes of the girders, the paper took one infinitesimal section of truss girder as a basic element, and then the additional curvature of simply supported truss girders caused by the slip effect under uniformly distributed load was deduced. Then the conjugate beam method was used to calculate the mid-span deflection. The formula results were compared with the experimental and Finite Element Method results. It was shown that the analytical solution agrees well with the experimental data, and can provide theoretical basis for the study and the engineering application of the truss girders.