上翼缘受侧向支撑的固端钢梁整体稳定分析

采用ANSYS有限元程序对受混凝土板刚性约束的两端固定H型钢梁进行非线性屈曲分析,分别研究了钢梁在高度变化和下翼缘宽度变化两类情况下梁负弯矩段的侧扭屈曲对梁整体稳定的影响,结果表明上翼缘有刚性侧向支撑的两端固定H型钢梁存在部分屈曲后强度,钢梁在屈曲后承载力能继续提高,构件未发生过度变形前可充分利用钢梁的部分塑性,提高其设计承载力;另外下翼缘宽度变化对两端固定梁整体稳定影响较大,梁截面较高同时下翼缘又比较窄时,负弯矩段的侧扭屈曲会使钢梁发生过度变形,对下翼缘无侧向支撑的H型钢梁设计时仍需考虑其整体稳定性.

Stability analyses of fixed end beam with lateral bracing on its top flange

The effect of negative moment on stability of fixed end H beam with top flange braced is studied in this paper,by using the finite element nonlinear analysis.It is shown that the fixed end beam H with the lateral bracings on top flange exist the post buckling strength which can enhance its carrying capacity,and partial plasticity of beam can be made use of before excessive deformation occurring.The lower flange width has considerable effect on integral stability of the fixed end beam.Lateral buckling in the negative moment region will cause the fixed end H beam with the narrowed lower flange and shorter section to excessive deformation.The integral stability has to be taken account of in design of fixed end H beam without bracing on lower flange.