组合框架-混凝土核心筒混合结构多层次地震损伤演化规律研究

Composite frame-concrete core wall structures are widely used in high-rise buildings, since they have the advantages of both steel and concrete structures. However, the energy dissipation and damage failure mechanisms of different material members in different locations of the structure are of obvious distinction, which makes it more difficult to predict and control the response performance and damage process of the structures. Besides, for the lack of practical earthquake information, the study of its seismic performance is not sufficient. This project is aimed at studying the damage evolution process and the seismic damage mechanisms of the composite frame-concrete core wall structures under earthquakes, by the method of combining the theoretical analysis, numerical analysis and experimental verification. The difference of the energy dissipation and damage evolution mechanisms between different material members will be fully considered, and the consistent damage model and the corresponding consistent performance levels of structural members of different materials will be built. Moreover, the project will discover the characteristics of the seismic damage of the structures under member level, floor level and the global level, and the inner relation between them. Then, the analysis model of the seismic damage in the evolution from low level to high level will be constructed. Finally, the reasonable seismic performance index of the composite frame-concrete core wall structures will be determined, as well as the corresponding quantitative relation between the seismic damage and the seismic performance index of the structures, thus establishing the preliminary basic theory and method of effective control of the seismic damage of the composite frame-concrete core wall structures.

组合框架-混凝土核心筒结构综合了钢结构和混凝土结构的优点，广泛应用于高层建筑结构中。但由于不同材料构件在结构不同部位提供的能量耗散机制及损伤破坏机理存在明显差异，结构响应性态和破坏过程更加难以预测和控制。由于缺乏实际震害资料，对其抗震性能的研究尚不充分。为保障组合框架-混凝土核心筒结构的地震安全和控制地震损伤，本项目拟采用理论分析、数值模拟和试验验证相结合的方法，对组合框架-混凝土核心筒混合结构在地震作用下的损伤演化过程与破坏机理进行研究。充分考虑不同材料构件耗能机制及损伤破坏机理的差异，建立不同材料构件的一致损伤模型及对应的一致性能水准；揭示构件、楼层和整体结构不同层次的地震损伤演化特点及内在联系，建立从低层次向高层次演化的地震损伤评估模型；确定合理的抗震性能指标，获得结构地震损伤状态与抗震性能指标之间的对应关系，从而初步形成组合框架-混凝土核心筒混合结构地震损伤评估的基本理论和方法。

不同材料构件在结构不同部位提供的能量耗散机制及损伤破坏机理存在明显差异，组合框架-混凝土核心筒结构响应性态和破坏过程难以预测。本项目对其在地震作用下的损伤演化过程进行研究，主要研究成果如下：1）基于附加约束应力作用效应，构造了考虑约束效应的混凝土本构方程，建立了适用于转换柱和型钢混凝土柱的数值分析方法。进行了广泛的参数分析，研究了构件变形和受力特点，提出了合适的抗剪承载力公式。并探讨了自阻尼混凝土局部增强对构件破坏的影响；2）基于Park-Ang损伤模型提出了不同材料构件一致损伤模型，利用收集的试验数据提出了组合系数计算公式。引入归一化参数，建立了一致损伤性能水准；3）通过一混合框架结构和一钢筋混凝土框架结构振动台试验分析算例，验证了采用一致损伤指标在楼层尺度进行性能评估的可靠性和有效性。4）对一混合结构的地震损伤进行研究，分析了截面属性、混凝土强度、钢材屈服强度和含钢率等参数对构件损伤的敏感程度；采用一致损伤指标研究了各构件发生不同程度损伤对楼层和结构整体损伤的影响，确定了不同失效模式下构件、楼层及结构损伤之间的内在关系。本项目成功探索了考虑不同材料构件性能差异的混合结构地震损伤的多尺度分析方法。