摘要
结构在水平荷载作用下产生水平侧移,竖向荷载作用于水平侧移而产生的内力与侧移增大的现象称为二阶效应,设计时有必要考虑此放大。支撑结构本身的变形特性不同时,这种二阶效应计算公式应有区别,但是目前各国规范只有剪切型结构的二阶效应系数。本文对在水平力和竖向力作用下的框架-弯剪型支撑体系中框架柱的柱端弯矩放大系数,提出了简单的计算公式,用ANSYS有限元计算了各种算例,算例中包括了变截面、变刚度、变轴力等各种形式。比较了有限元结果与近似公式,结果表明提出的公式精度良好。
Column＇s bending moments are increased duo to second order effect. Currently, the moment amplification factors are considered only for shear-type structures where inter-storey interaction is not obvious. This paper presents a study on the moment amplification factors in frames braced by a vertical Timoshenko＇s Cantilever, i.e. both shear and flexural deformations in the cantilever must be considered. An approximate formula for the amplification factor on the bending moment in the frame is proposed. Comparison with results from FEM for structures with varied axial force and varies rigidities shows the reasonable accuracy of the proposed formula.
出处
《建筑钢结构进展》
2008年第5期35-44,共10页
Progress in Steel Building Structures
关键词
弯矩放大系数
二阶效应
框架
支撑
弯剪型梁
moment amplification factor
P-△ effect
frame
brace
Timoshenko＇s beam
