考虑层相互作用的框架柱计算长度

COLUMN EFFECTIVE LENGTH CONSIDERING THE INTER-STORY INTERACTION

在放弃了传统计算长度系数法的三个理想化假定后 ,提出了有侧移框架失稳时考虑层间支援的框架柱计算长度的计算方法。对于两层框架 ,求解一个一元二次方程得到各柱柱端的转动约束 ;对于三层框架 ,求解一个一元三次代数方程 ,得到各柱柱端的转动约束。进而由传统公式或规范附表可得到计算长度系数值。对于更多层的情况 ,先确定薄弱层 ,并假设薄弱层的上下层柱远端的梁端约束全部提供给与薄弱层相邻层的柱 。

With three assumptions of the conventional effective length approach abandoned,a new approach is proposed by which column effective length considering inter-story interaction can be obtained in un-braced two-story or three-story frames.A quadratic equation with one variable for two story frames and a cubic equation with one variable for three story frames are derived from which the rotational restraint provided to each column end may be solved and the effective length factors can then be determined by the traditional formula or tables.For frame of more than 3 stories,a sub-assemblage of three stories is taken out,and this method is also applicable for this sub-assemblage,and the result is of high accuracy.