钢管混凝土框架-剪力墙结构抗连续倒塌能力评估及设计方法

Concrete-filled steel tubular frames with reinforced concrete shear walls structures have been widely used in high and super-high buildings structures. However, the research on mechanical performance of progressive collapse and design method were relatively deficient, both in China and abroad. This project will study the collapse mechanical mechanism and design approaches of concrete-filled steel tubular frames with reinforced concrete shear walls structures subjected to the accidental load. The collapse experiments will be performed of this type of structure when the key members were destroyed by anthropogenic factor. The mechanical behavior and mechanism of the composite structure with shear walls should be investigated based on experiments and numerical simulation. A 3-D finite element analysis(FEA) model will be developed to simulate the performance of the tested specimens. The test results are used to verify the FEA model. Parametric studies were carried out in a common scale for practical engineering using the validated FEA model under various physical and geometrical parameters, to study the influence law of resistance capacity index and displacement of the indicators, and given the collapse discriminated criterion of the composite structure with shear walls. The theoretical research was performed to investigate resistance collapse bearing capacity in beam mechanism and catenary mechanism. And then the theory of three dimensional calculation model of composite structure with shear walls was given considering the effect of reinforced concrete slab contribution. Tie force (TF) method is one of the major design methods proposed by foreign codes to resist progressive collapse, but the related researches are still lack in China. So the project will improvement of tie force (TF) collapse resistance design practical method, providing some reference for the research and collapse design of the composite structure.

钢管混凝土框架-剪力墙结构体系已经广泛应用于我国高层和超高层建筑之中，目前国内外尚缺少其抗连续倒塌性能及设计方法的研究。本课题以研究该类结构的倒塌机理和倒塌能力以及设计方法为目标，进行关键构件失效后钢管混凝土框架-剪力墙结构的抗倒塌试验研究，明晰结构的倒塌机理和破坏模态。建立基于三维弹塑性理论的有限元数值模型对试验试件进行有限元分析，基于全过程倒塌机理分析，进行该类结构抗倒塌性能影响参数分析，研究不同物理和几何参数对该类结构的抗力指标和位移指标的影响规律，提出该类结构的抗连续倒塌判定准则。在此基础上，进行该类结构在小变形作用下梁机制承载力和大变形作用下悬链线机制承载力的理论计算方法研究，给出考虑钢筋混凝土楼板贡献效应的三维理论计算模型；此外，针对现有抗连续倒塌设计方法中拉结强度法的存在不足，提出改进的拉结强度抗倒塌设计实用方法，为该类结构的倒塌研究和设计提供一定的参考。

钢管混凝土框架-剪力墙结构体系已经广泛应用于我国高层建筑之中，目前国内外尚缺少其抗连续倒塌性能及设计方法的研究。本项目以研究该类结构的倒塌机理和倒塌能力以及设计方法为目标，首先进行了不同工况下两层两跨钢管混凝土框架以及框架-剪力墙结构的抗倒塌试验研究，观察了不同倒塌试件的全过程破坏特征和破坏机理，实测了失效柱顶荷载-位移全过程关系曲线，绘制了不同梁、柱、板等关键部位应变-位移关系曲线，发现不同失效工况下，角柱失效后试件整体破坏主要集中于失效跨，破坏特征主要以钢梁断裂和扭曲变形为主，中柱失效后试件主要破坏特征为钢梁开裂及屈曲变形，失效柱附近组合板混凝土被压溃，左跨钢梁与压型钢板组合板局部发生分离；钢管混凝土框架-剪力墙结构的主要破坏特征为钢梁的断裂和屈曲变形，失效柱附近组合板混凝土被压溃，剪力墙混凝土出现斜向45°的裂缝，且二层剪力墙暗柱钢筋与钢梁发生分离，钢梁与压型钢板组合楼板局部发生分离。其次，基于ABAQUS精细化建模，进行了该类结构的全过程倒塌机理分析，明晰了不同失效工况、不同倒塌试件以及墙体和支撑结构对钢管混凝土框架抗连续倒塌承载力和破坏特征的影响；基于机理分析，开展了不同几何参数、物理参数和荷载参数作用下的该类结构的抗连续倒塌参数分析，获得了影响该类结构抗连续倒塌承载力的主要影响参数，提出了局部加强法抗连续倒塌设计方法。最后，基于试验研究和数值模拟，给出了该类结构在不同失效工况下的理论计算模型，根据试验结果进行该类结构抗倒塌机制的计算和分析。在此基础上，开展了基于采用能量等效原理分析该类结构的倒塌动力效应，提出了钢管混凝土组合结构抗连续倒塌过程中的动力放大系数(DIF)计算公式，并对该类结构的抗倒塌能力进行了简要评估，并从宏观结构层面提出了该类结构的抗连续倒塌设防对策，为工程应用和设计提供一定的参考。