框架-核心筒高层混合结构的三维空间弹塑性抗震分析

Seismic performance evaluation using nonlinear time history analysis with three-dimensional structural model for a hybrid frame-core tube structure

准确预测结构在强震作用下的非线性行为,对评估结构抗震设计的安全性具有重要意义。在总结了现有的结构弹塑性分析模型基础上,以通用有限元程序MSC.MARC为平台开发了一系列新的结构弹塑性分析模型。通过对试验的模拟,表明这些模型可以直接将构件的非线性节点力(轴力、剪力和弯矩)、节点变形(平动和转动)和材料的非线性应力-应变行为联系起来,能够较好地模拟各种复杂受力构件的滞回行为和轴力-双向弯曲-剪切耦合行为。同时,借助通用有限元程序的前后处理功能和非线性计算功能,这些模型可以细致地模拟地震作用下整体结构的三维非线性地震响应。利用所开发的分析模型,对一个复杂框架-核心筒高层混合结构实际工程进行了弹塑性动力时程分析,较好的模拟了该工程结构在地震作用下的复杂抗震行为,并根据不同强度地震作用下的分析结果,说明该工程外框架与4个子筒组成的核心筒可组成有效的双重抗震结构体系,并具有连梁、子筒和外框架三道抗震防线,为工程抗震设计提供依据。

Accurate prediction for the structural nonlinear behaviors is important to the structural safety assessment against earthquakes. Some new models, which are used to establish three-dimensional structural model for nonlinear time history analysis under strong earthquakes, are presented. In these models, the material stress-strain relationship can be connected directly with the force-displacement behavior of the structural elements, such as beams, columns, shear walls and core tubes, so that the complicated coupled axial force-bending moment-shear force behaviors, as well as the corresponding cycle behaviors, can be properly simulated. With the secondary development user subroutines, convenient pre and post process functions and extinct nonlinear capacity of general purpose FEA software of MSC. MARC, the spatial seismic responds of structures can be simulated in detail. A practical hybrid frame-core tube structure was analyzed with dynamic time-history analysis based on these models and the complicated seismic behaviors of the structure were simulated. According to the analytical results under ground motions with different intensities, the exterior frame and the core tube made up of four sub-tubes in this structure can form effective dual seismic resistant system which has three seismic fortification lines： coupling beam, sub-tubes and exterior frame.