饶芝英  童根树    （浙江大学土木系  杭州 310027）

[提要]  提出了与钢结构稳定性计算有关的多高层钢结构的分类，由此可以更好地理解钢结构稳定性的计算方法，合理选择钢结构稳定计算的图表或公式，判断某些钢结构规范稳定性计算条文的合理性。
[关键词]  钢结构  稳定性  框架  支撑  高层建筑

A classification of multistory and tall steel structures is presented in seismic design, which is closely related to the stability design. Based on this classification, the designer may make a correct decision on what kind of method should be used in the structural analysis( first order or second order analysis) and select an appropriate formula or table from the code to determine the column effective length or calculate the column load-carrying capacity. This paper summarized the definitions of total 7 technical terms, i. e. sway and non-sway frames, laterally stiff structure and laterally flexible structure, and strongly braced, weakly braced and unbraced frames. The presented classifying method is based on a research on the buckling of unbraced,weakly braced ancl fully braced frames. Criteria for judging whether a structure is fully braced or not is presented. The stability design formula for weakly braced frames is put forward.
Keywords:  steel structure; stability; frame; brace; tall building