程  鹏    童根树
    （浙江大学土木系  杭州 310027）

[提要]  通过大量的计算，对现行《门式刚架轻型房屋钢结构技术规程》中的考虑腹板局部屈曲的薄壁工形截面压弯强度计算进行了分析。指出了《规程》中的缺陷及其改进方法：一是对单轴对称截面较大翼缘受压的情况，除了验算受压区屈服的情况外，还应补充验算受拉翼缘先屈服的情况，作者给出了具体的验算公式。二是用《规程》中的方法进行计算时，只在轴力作用下，腹板宽厚比（h_w /  t_w）√f_y / 235 > 217时， ρ<o，即整个腹板受压区都失去作用，这与实际情况不符合。对此，使用美国AISI规范公式进行了计算，给出了以美国AISI规范公式为基础的精度良好的简化近似公式，以供参考使用。
[关键词]  强度计算  有效面积  薄壁工形截面

The current code presents a complicated procedure for calculating the strength of beam-columns with thin-walled H-section considering the local buckling of webs. This paper calculates the interactive relations between the axial force and bending moment based on the current code procedure. lt is found that code CECS102:98 gives an unsuitable in-teractive curve when the web slenderness A.is greater than 3.87. This paper presents a simplified formula for the in-teractive curves based on AISI specification, which has a very good accuracy compared with the code method. For monosymmetrical H-sections, the tensile side of the section may yield first, the current specification pays no attention to this problem at alI. A simple formula is also put forward for this case.
Keywords: strength calculation; effective section; thin-walled H-section