超限高层结构抗震性能化设计方法探讨

Discussion on performance-based seismic design method of out-of-code high-rise structures

随着我国超限高层建筑的大量涌现,团体标准《建筑结构抗震性能化设计标准》已颁布实施,对超限高层结构的抗震设计产生一定的影响。针对超限高层结构抗震性能化设计和抗震设防审查中若干值得探讨的问题,首先总结了超限高层结构抗震性能化设计方法;然后重点探讨了超限高层结构抗震性能化设计的3个重要指标:剪重比、框剪比和中震墙肢拉应力,提出了上述指标不满足规范要求时可采用基于抗震性能化设计的解决措施;最后,阐述了基于预设屈服模式的抗震性能化设计新方法。结果表明:长周期高层建筑的剪重比不满足限值时,建议通过修正反应谱的长周期段,验算结构的侧向刚度;对于框剪比限值,建议根据大震下的内力重分布规律对小震设计的框架剪力进行调整;基于预设屈服模式的抗震设计方法可实现对超限结构破坏模式的控制。

With the emergence of a large number of out-of-code high-rise structures in China,standard for performance-based seismic design of building structures has been formally implemented,which has a certain impact on the seismic design of out-of-code high-rise structures.Aiming at some problems worth to be discussed in the performance-based seismic design and the seismic fortification review of out-of-code high-rise structures,firstly,the performance-based seismic design method of out-of-code high-rise structures was summarized;secondly,three important indexes of out-of-code high-rise structures including the shear-gravity ratio,the frame-shear ratio and the tensile stress of the wall panel under middle earthquake were emphatically discussed,and corresponding solutions based on performance-based seismic design were proposed when the above indexes do not meet requirements of the codes;finally,the new performance-based seismic design method based on the predetermined yield mode was expounded.The results show that,when the shear-gravity ratio of long-period high-rise buildings does not meet the limit value,it is recommended to check the structural lateral stiffness by modifying the long-period segment of the response spectrum.For the frame-shear ratio limit,it is recommended to adjust the frame shear force designed under small earthquake based on the internal force redistribution under large earthquake.The seismic design method based on predetermined yield mode can control the failure mode of out-of-code structures.