上海环球金融中心大厦结构抗震性能研究

Study on seismic behavior of Shanghai World Financial Center Tower

上海环球金融中心大厦结构高度492m,地上101层,高宽比8.49,拟建成为世界上结构高度最高的建筑。该建筑总高和高宽比都超过了我国《高层建筑混凝土结构技术规程》(JGJ 3—2002)所规定的限值,为研究该超限的复杂超高层结构体系的抗震性能,进行了1∶50比例的微粒混凝土整体模型的地震模拟振动台试验,得到了结构在7度多遇、7度基本、7度罕遇和8度罕遇地震作用下结构的动力特性、动力反应以及结构的破坏型式。利用ANSYS对结构进行了有限元分析,并与试验数据进行了对比,对比结果表明试验与理论分析结果吻合良好。研究得到:该结构体系在7度多遇至7度中震地震作用下结构自振频率基本不变,结构基本处于弹性阶段;在7度大震作用下,结构自振频率有所下降,最大层间位移角满足规范的弹塑性变形要求;在8度大震作用下,结构局部出现混凝土开裂和压碎现象,但能维持结构不倒塌的工作状态。综合研究结果表明该结构体系满足小震不坏、中震可修、大震不倒的抗震设防要求。

The 101-storey Shanghai World Financial Center is 492m above ground and its aspect ratio of height to width is 8.49, which makes it possible to be the tallest building in the world when completed. The overall height and the aspect ratio clearly exceed the limits stipulated by Chinese technical specifications for concrete structures of tall building （JGJ3-2002）. A scaled model was made and tested on shaking table to study its dynamic characteristics and seismic responses under various seismic actions from frequent to rare earthquake levels. A 3-D finite element analysis was conducted to evaluate the structural seismic performance. The comparisons between the analytical and experimental results showed that the natural frequencies remained almost constant demonstrating an elastic behavior of the structure until basic earthquake of intensity 7. Under rare earthquake of intensity 7, natural frequencies decrease to some extent. Corresponding to rare earthquake of intensity 8, concrete crush occurrs but no collapse happens to the model. The maximum inter-story drifts under different earthquake levels are smaller than the allowable limits stipulated in Chinese code. Conclusion can be drawn that the structure can meet the requirements of no damage under frequent earthquake, repairable damages under basic earthquake and no collapse under rare earthquake.