超高层结构考虑加强层构件失效后的结构性能

Structural performance of super high-rise building with reinforced layer storiesunder the failure of special members

在超高层结构设计中,加强层的布置往往相对集中,容易引起刚度突变。根据已有的强震记录及工程试验,选定伸臂桁架上方框架柱为薄弱部位,假定在强震作用下,结构因刚度突变引起加强层局部构件失效,通过构件删除法分析了剩余结构的竖向承载能力和抗震能力,指出了局部构件失效进而导致加强层以上外圈结构在余震作用下可能倒塌的连锁反应过程。提出在加强层设计中,应同时重视加强层设置引起的加强层与其上、下层之间的刚度突变。建议在加强层上方设置数层环带桁架,既可以有效减弱刚度突变,也可托举强震下可能失效的框架柱的上方结构,避免结构连续倒塌。

The reinforced layer was designed to be few and strong in super high-rise buildings,which can cause saltation in stiffness. According to the earthquake records and the engineering experiment,the frame columns above the truss was selected to be weak part,which is supposed to be failed under seismic load caused by saltation in stiffness. The vertical load and seismic resistance capacity of the residual structure were analyzed by deleting the failed members. A chain reaction was pointed out that the structure out of the core tube will collapse under the aftershock load with the failure of the special members. The stiffness ratio of reinforced layer between the upper and lower layer should be valued. Several belt truss were suggested set above the reinforced layer to reduce saltation in stiffness and carry the failed frame under earthquake,which avoids progressive collapse.