上海中心大厦结构抗震分析简化模型及地震耗能分析

Study on simplified modeling and energy dissipation distribution of the Shanghai Tower

以结构高度为632 m的上海中心大厦结构为工程背景,建立其二维非线性简化分析模型,提出主要构件的简化分析方法,并与上海中心大厦结构精细有限元分析模型的模态、静力和弹塑性时程分析结果进行比较,对简化分析模型的准确性进行验证。结果表明:建立的简化分析模型能较好地反映上海中心大厦的基本动力特性,近似反映结构的地震响应。以FEMA P695推荐的22组远场地震动记录为基本输入,基于简化模型的弹塑性时程分析结果,分析不同地震强度下上海中心大厦结构不同构件对塑性滞回耗能的贡献及其总耗能沿高度的分布。分析表明:由于高阶振型影响显著,上海中心大厦结构的总塑性耗能主要集中在结构上部的4个区段,且伸臂桁架是主要的塑性耗能构件。本研究可为进一步完善超高层建筑结构抗震设计理论提供参考。

Based on the Shanghai Tower project,an actual super-tall building with a height of 632 m,the simplified modeling methods for the main components were discussed in detail and then the simplified 2-D nonlinear model was developed.The accuracy of the simplified model was validated by comparing the model,static and time-history analysis results of the refined finite element model.The validation indicates that the simplified model can represent the basic dynamic characteristics of the building and predicts the elastic and nonlinear seismic responses well.Taking the 22 pairs of ground motions suggested by FEMA P695 as the basic seismic input,the energy-dissipation contribution of different components and the distribution of the total energy-dissipation over the height under different seismic intensities were determined with the proposed simplified model.The results indicate that due to the significant contributions of high-order vibration modes,the total hysteretic energy distribution is mainly concentrated in the upper four zones of the building and that the outrigger is the major energy dissipation component.It will provide useful information for further development of optimum design for super-tall buildings.