确定框架和排架柱计算长度的实用图表法

The practical calculation charts to determine column effective length of frame and bent frame

确定柱的计算长度是稳定验算的关键一环,对此,GB50017—2010《钢结构设计规范》中给出了一些相关的计算公式和表格,但这些公式和表格仍存在两方面的不足:一是这些公式和表格基于计算假定只适用一般情况,对于一些特殊情况,如框架各柱内的轴力或各排架柱的轴力和柱高相差较大时,这些公式和表格就不再适用了;二是使用这些公式和图表难以得到计算长度随各相关参数变化的直观表现。针对这些不足,本文作者利用二阶位移法推导了相关的公式并制成了确定计算长度的实用图表,利用这些图表可快速地确定计算长度,并可得到计算长度随各参数变化的直观趋势。

Calculation of effective length of columns is key of stability checking in design, therefore some formulas and tables are given in Code for Design of Steel Structures （GB 50017--2010） ,which show some application limitations. Firstly these formulas and tables are made based on assumptions for regular frames. For some special cases ,such as existence of the large difference of the column axial force or column length among the framework columns, these formulas and tables are no longer applicable. Secondly it is difficult to find out the trends of effective length cause by the related parameters. The practical calculation charts are derived by authors by using the displacement method with the second-order theory, which can be used to quickly determine column effective length and show intuitive trends of the lengths.