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两端支承钢梁的设计方法不适用于抗侧向屈曲的悬臂梁。悬臂梁与两端支承梁的约束不同,其最大位移和转角发生在自由端,而不是在跨中附近。因此,它们的屈曲模态不一样。这些方法考虑了弯矩分配法对两端支承梁弹性及非弹性屈曲的影响,但不适用于悬臂梁。悬臂梁的侧向屈曲设计法是对端支承梁设计法的修正,但其精度不高,有时过于保守,某些情况下,不能用于设计。使用弯矩分配法进行结构的屈曲分析,总结了该方法对悬臂梁弹性屈曲的影响。改进两端支撑梁的非弹性屈曲设计方法,使其能考虑弯矩分配法对悬臂梁非弹性屈曲的影响。改进的方法与简支梁的设计法是一致的。以某工程为实例,演示了此方法的应用。
Design methods for steel beams supported at both ends are not suitable for cantilever beams that resist lateral buckling. The cantilever beams have different restraints than the two support beams, and their maximum displacement and rotation occur at the free end, not near the mid-span. Therefore, they have different buckling modes. These methods take into account the effect of bending moment distribution on the elastic and inelastic buckling of the supporting beams at both ends, but do not apply to cantilever beams. Lateral buckling design of cantilever beams is a modification of the design method of end support beams, but its accuracy is not high, sometimes too conservative, and in some cases can not be used in design. The buckling analysis of the structure is carried out by using the moment distribution method, and the influence of this method on the elastic buckling of the cantilever beams is summarized. The non-elastic buckling design method of the beam with both ends is improved so that it can consider the influence of the moment distribution method on the inelastic buckling of cantilever beams. The improved method is consistent with the simple beam design method. Taking a project as an example, we demonstrate the application of this method.