冷弯薄壁C形钢柱翼缘转动约束刚度简化计算

畸变屈曲是冷弯薄壁型钢构件的主要破坏模式之一，按翼缘模型计算其弹性畸变屈曲应力时需要确定腹板对翼缘的转动约束刚度.现有转动约束刚度计算公式较复杂，求解过程需要进行一次迭代.为了简化计算过程，提出了冷弯薄壁C形钢柱翼缘转动约束刚度简化计算方法.该方法在Lau和Hancock公式的基础上，结合我国《冷弯薄壁型钢结构技术规范》（GB50018 2002）中关于腹板和翼缘局部屈曲系数的规定而导出的，并根据Lau和Hancock公式计算结果对其进行了修正.与有限条分析值对比表明：该方法可以准确、方便地计算转动约束刚度，能够应用于冷弯薄壁型钢C形截面柱的设计计算.

Simplified calculation of rotational restraint stiffness for flange of cold-formed thin-walled C-shaped steel column

The distortional buckling is one of the main failure modes for cold formed thin walled steel components. When the elastic distortional buckling stress of steel components is calculated with flange model, it is necessary to determine the rotational restraint stiffness provided by the web plate to the flange. However, the current calculation formula for the rotational restraint stiffness is complicated, and one iteration is required in the solution process. In order to simplify the calculation process, a simplified calculation method concerning the rotational restraint stiffness for the flange of cold formed thin walled C shaped steel column was proposed. Based on Lau and Hancock’s formulas, the proposed method was derived in combination with the regulations concerning the local buckling coefficients of the web plate and flange in the Technical Code of Cold Formed Thin Walled Steel Structures （GB 50018 2002） in China, and it was then modified according to the results calculated by Lau and Hancock’s formulas. Compared with the finite strip analytical values, it is noted that the proposed method can calculate the rotational restraint stiffness accurately and conveniently, and can be used for the design and calculation of cold formed thin walled C shaped steel columns.