钢-混凝土组合梁在负弯矩作用下的屈曲失稳系数研究  

BUCKLING COEFFICIENT OF STEEL-CONCRETE COMPOSITE BEAMS IN NEGATIVE BENDING

作　　者：贾远林[1,2] 陈世鸣[1] 

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学建筑设计研究院,上海200092

出　　处：《工程力学》2009年第11期121-126,共6页Engineering Mechanics

基　　金：国家自然科学基金项目(50678132)

摘　　要：组合梁与钢梁的侧扭失稳机理与形态存在显著差异,与纯钢梁的失稳相比,组合梁中钢梁上翼缘受到刚度较大的混凝土板约束,表现为与纯钢梁不同的畸变失稳。采用钢构件的Perry-Roberson失稳设计曲线来计算组合梁的失稳极限承载力的适用性急需验证。采用组合梁力学模型,考虑钢梁初始几何缺陷和残余应力影响,进行了组合梁有限元非线性稳定分析,计算结果与试验实测值吻合。通过改变截面参数,对43组组合梁的极限承载力进行了计算,根据EC4截面分类方法,定义了1类、2类截面和3类、4类截面的长细比,研究表明:负弯矩下的组合梁可通过长细比参数采用我国的钢柱稳定曲线进行求解。A steel-concrete composite beam, whose steel top flange is restrained laterally by the stiff concrete slab, may encounter lateral buckling in distortional mode when in negative bending, which is sharply different from the lateral torsional buckling of bare steel beams. However, the design approach uses the Perry-Roberson formula, which is basically derived from bare steel component tests. To solve this contradiction, inelastic FE buckling analysis is carried out on composite beams in negative bending based on the proposed restrained torsional buckling model. The initial geometric imperfection and the residual stresses are considered. The FE results agree well with the test results. Changing cross-section parameters, 43 groups of composite beams in uniform negative bending are studied. In accordance with EC4, slenderness of the considered beams is defined for, class 1-2 cross-section and class 3-4 cross-section respectively. It is demonstrated that the Chinese Codified steel column design curves can be used in predicting the buckling strength of composite beams with the modified slenderness.

关 键 词：组合梁 失稳 负弯矩 极限承载力 稳定系数 

分 类 号：TU398.9[建筑科学—结构工程] TU311.2