【作者】 王金鹏；

【导师】 童根树；

【作者基本信息】 浙江大学 ， 结构工程， 2004， 硕士

【摘要】 本文通过分析一个简单的两层框架，表明如果采用传统计算长度系数法的理想假定，则必然会导致梁端约束在上下层柱之间的不合理分配。在放弃了传统计算长度系数法的三个不合理假定后，本文提出了两层和三层框架失稳时，考虑层间支援的框架柱计算长度的很精确的计算方法。对于两层框架，通过求解一个一元二次代数方程得到各柱柱端的转动约束；对于三层框架，通过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得到各柱的计算长度系数值。对于更多层的情况，先判断薄弱层，再假定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，取出薄弱层及其上下层的梁柱，按前面处理两层或三层框架的方法可以得到薄弱层柱很精确的计算长度系数，相应导得其它层柱的计算长度系数。对于更为一般的单跨不对称框架和多跨框架，本文采用梁柱合成的方法求解，精度也很理想。更多还原

【Abstract】 Through an analysis of a simple two-story frame, this paper revealed that the assumptions used in current effective length method led to unrealisticdistribution of beam restraints among the connected columns. With three assumptions of the conventional effective length approach discarded, a newapproach is proposed by which column effective length consideringinter-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 may be solved and the effective length factors can then be determined by the traditional formula or tables. For frames of more than 3 stories, the weakest story is first selected and a three-story sub-assemblage including the weakest column is taken out, and the proposed method is applied, the effective length of the weakest column is thus obtained, the effective length of the remaining columns are computed through a pre-defined relations. Because the sub-assemblage included beams at far ends of the columns above and below the column under consideration, the far end condition (hinged or fixed) may be considered easily.更多还原