聂建国
    （清华大学土木系  北京 100084）

[提要]  对钢-混凝土组合梁的长期变形问题进行了分析和讨论，指出我国现行《钢结构设计规范》关于组合梁长期变形的计算值偏小，并建立了组合梁的长期刚度计算公式，反映了混凝土徐变系数大小的影响，同时还考虑了混凝土收缩对变形的影响。公式意义明确，形式简单，应用方便。
[关键词I  钢-混凝土 组合梁  长期变形  徐变  收缩

Based upon the discussion and analysis for long-term deformation of composite beams of steel and concrete, it is found that the long-term deformation is under- evaluated by the current code "Design of
Steel Structures" used in China. The formulae of long - term rigidity is derived for composite beams under sustained load, in which the effect of creep and shrinkage of concrete is taken into account, The formulae in the paper, with clear physical concept, are simple and easy to be used in practice.
Keywords: composite  beam; long - term  rigidity; shrinkage; creep; concrete