周向明  李国强  丁  翔
    （同济大学建筑工程系  上海 200092）

[提要]  将高层钢-混凝土混合结构分为外部钢框架和内部混凝土核心筒两部分。外部钢框架进一步简化为半刚架和相应的弹性阶梯形等效弯曲杆的串联体系，这种简化模型能考虑柱轴向变形对结构动力反应的影响；内部混凝土核心筒则采用弯剪两弹簧墙单元模型，简化后的框架和混凝土芯筒之间通过位于楼面标高处的水平刚性连杆连接。考虑到几何非线性对高层结构动力反应的影响，再用一竖向受载杆与上述简化结构并联，从而得到了高层混合结构简化动力分析模型。对。个25层混合结构的1/20试验模型进行了理论分析，并与模拟地震振动台试验结果进行对比。分析表明，提出的简化模型能反映混合结构主要的动力特征，可大大减少计算自由度和降低计算工作量，且具有较好的计算精度。
[关键词]  钢框架  核心筒  混合结构  弹塑性  地震反应分析  半刚架模型  弯剪两弹簧墙单元模型

The modeling of hybrid structures comprising external steel frames and core concrete tube is simplified for nonlinear seismic analysis. The external steel frames are simplified as a series of half frames and the core-tube is modeled as a bending and shearing two-spring system. The two parts mentioned above are connected with horizontal rigid bars at the level of the floors. To verify the effectiveness and reliability of the proposed simplified model for analysis of elasto-plastic response of hybrid structures subjected to earthquakes, shaking table tests were conducted on a small-scale model of 25-story hybrid structure building. Comparing with the data obtained from the shaking table test, it is found that the theoretical analysis by employing the proposed analytical model can predict the response of the moclel building with satisfactory precision.
Keywords:  hybrid structures; tall building; elasto-plastic analysis; seismic response