带加强层结构在加强层处的刚度发生剧变,从而引起侧向荷载下结构内力分布及变形的相应变化,地震作用下此类结构容易形成薄弱层,因而抗震性能较差。同时,带加强层的建筑物很多属于超限复杂高层建筑结构,无法直接套用规范方法进行抗震设计。根据带加强层高层建筑结构的受力变形特点及国内外研究者的研究成果,结合模态推覆分析理论和能力谱抗震设计方法,本文对带加强层高层建筑结构的受力变形性能作了详细的分析,提出此类结构基于能力谱法的抗震设计方法。此法采用受力层间侧移角作为性能指标,并针对加强层和普通楼层采用了不同的性能水准量化值,根据结构特点以底部和加强层上部两层楼作为薄弱层进行验算,最后通过算例验证所提方法的可行性。
Horizontal strengthened stories can decrease the lateral displacement and increase the lateral stiffness of structures. But the internal force and strain distribution will be changed by the strengthened stories, which may induce weak stories of the structure. Structures with strengthened stories are mostly super tall buildings and can not be designed according to the current code directly. This paper proposes a capacity spectrum-based seismic design procedure on the basis of modal pushover theory and capacity spectrum method. The proposed method adopts actual interstory drift ratio as the performance index and uses different performance levels for strengthened stories and reg- ular stories. Bottom stories and two stories above each strengthened stories are taken as the key stories in the proposed method. Calculating example shows that the proposed procedure is applicable for actual design.