中文摘要：

考虑钢梁初始几何缺陷影响和残余应力影响，对体外预应力组合梁进行了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25组组合梁在初始几何缺陷、不同残余应力分布和不同综合力比下的承载力进行计算，给出了预应力组合梁的长细比计算公式，与我国现行钢结构规范钢柱稳定曲线进行了比较．研究表明，承受负弯矩作用的体外预应力组合梁可用文中提出的长细比作参数采用钢柱稳定曲线进行计算．

英文摘要：

Based on the proposed restrained torsional buckling model, inelastic finite element buckling analysis is made of the composite beams in negative bending with a consideration of the initial geometric imperfection and the residual stress patterns, and the analysis results agree well with the test results. By varying cross-section parameters, 25 groups of composite beams under negative uniform bending with initial geometric imperfection and different patterns of residual stress in steel beams are studied by means of the FE method. The slenderness of the studied beam is defined and the calculated result is compared with the Chinese codified steel column design curves. It is demonstrated that the Chinese codified steel column design curves can be used in the assessment of the buckling strength of composite beams with the slenderness defined.