爆炸荷载下高层钢筋混凝土结构连续倒塌机制与模式研究

Research on Progressive Collapse Mechanism and Collapse Modes of High-Rise Reinforced Concrete Structure Under Blast Load

高层建筑结构构件尺寸较大,爆炸荷载作用下应力波传播造成的材料破坏效应不能忽略,需要采用精细化模型来分析其非线性响应行为与连续倒塌过程,计算效率低,实用性差.本文将多尺度建模方法引入到爆炸荷载作用下高层建筑结构的连续倒塌分析中,依据爆炸荷载作用下高层建筑结构非线性破坏与连续倒塌的特点,提出了多尺度模型不同区域的确定方法,使用该方法对某高层建筑结构的连续倒塌机制和倒塌模式进行了研究.结果表明,相同TNT当量炸药的爆炸荷载作用下,比例距离较小时,高层钢筋混凝土结构可能发生单柱失效-双向联合倒塌模式;比例距离增大至某一区间时,结构则可能发生多柱失效-竖向倒塌模式.多柱失效-竖向倒塌模式影响范围广,对结构危害大,应通过采取防护措施避免该倒塌模式的发生.

Because of the huge member size of high-rise building structure,material damage effect caused by stress wave propagation under blast load cannot be ignored,but the nonlinear response and progressive collapse process of high-rise buildings can only be well-captured by refined model with low efficiency. Multi-scale modeling method is used in this paper to analyze progressive collapse of high-rise building structure under blast load. The method for determining the different regions of multi-scale model is proposed based on the nonlinear structural response and progressive collapse characteristics of high-rise building under blast load. Progressive collapse mechanism and collapse modes of a typical high-rise building structure are studied. Results show that with the same amount of equivalent of TNT charge,vertical and horizontal progressive collapse mode caused by damage of one column tends to occur when scaled distance is small;vertical progressive collapse mode caused by damage of multiple columns may occur when scaled distance increases properly to a range,which brings much damage to structure and should be avoided by taking protective measures.