基于抽柱法的钢框架连续倒塌分析

Progressive collapse analysis of steel frame structure using removing column method

为较准确地进行连续倒塌分析,对抽柱法分析框架连续倒塌时柱失效时间取值、柱失效位置等问题进行研究.采用动力非线性计算方法分别对不同跨度和高度的空间纯框架及框架支撑结构进行连续倒塌模拟分析,得到结构动力效应与柱失效时间的关系曲线和各失效点的位移时程曲线.分析结果表明:随着柱失效时间的减小,结构的动力效应趋于收敛;柱失效位置对剩余结构的影响较大,某些情况下可能会导致剩余结构产生共振.建议在对结构进行连续倒塌分析时,取剩余结构竖向振动周期的1/10,不应大于1/5.柱间支撑作为抗连续倒塌的一道防线起到的缓冲作用能很好地提高结构抗连续倒塌能力.

The issues of column failure time and position of removing column method are studied in order to carry on the progressive collapse analysis more properly. The progressive collapse analysis on moment resisting frames of various span length, height and braced frames is analyzed. The curves of dynamic effect to column failure time and the displacement-time of column failure point are obtained. The results indicate that the dynamic effect of the residual structure converges with the decrease of column failure time; the influence of the position of the failure column is remarkable, and under certain circumstance the resonant vibration may occur. The time of column failure is recommended to be 1/10 of the time period of vertical vibration of the residual structures, and should not be more than 1/5. The capacity of resisting progressive collapse can be obviously improved by locating the braces which may act as the impact damper.