混合联肢PEC墙结构协同工作机理与抗震设计对策

Hybrid coupled PEC wall structure overcomes the shortcomings of brittle failure at the bottom wall and concrete coupling beams under seismic in reinforced concrete coupled shear wall, and is a two-stage energy dissipation system with excellent seismic performance. Meanwhile, the structure has large lateral stiffness, and is easy to assemble between components. However, the research on the cooperative working mechanism of hybrid coupled PEC wall structure is still insufficient, and the seismic design method is undefined. The project is aimed at studying the cooperative working mechanism of the system, establishing the mechanics model under seismic and achieving the seismic design strategy. A research method combining experimental research with theoretical analysis is proposed. Firstly, hysteretic behavior and cooperative working mechanism of rigid joints as well as an integral structure are analyzed, and seismic performance of the structure is evaluated comprehensively. Furthermore, a cooperative working mechanical model of the hybrid coupled PEC wall is proposed, and the mechanistic relationship between the overall failure of the structure and the damage of the component is constructed. Based on the mechanical model, the influence of coupling ratio on the cooperative mechanism and failure modes of the structure is studied, and the quantitative evaluation criteria for seismic performance is given. Finally, the reasonable failure mode control technology of hybrid coupled PEC wall structure under seismic is proposed, and the seismic performance-based design method is obtained. The research results have important theoretical significance and engineering application value for improving the seismic performance of the structural system.

混合联肢PEC墙结构克服了普通联肢墙地震作用下墙肢底部及混凝土连梁易脆性破坏的缺点，是一种抗震性能优良的两阶段耗能体系。同时，该结构侧向刚度大，构件间易于装配建造。然而针对混合联肢PEC墙结构协同工作机理研究还十分不足，抗震设计方法不明确。本项目以研究该结构体系的协同工作机理、建立地震作用下的力学模型、获得抗震设计对策为目标，拟采用试验研究和理论分析相结合的研究方法。首先分析钢连梁与PEC墙肢刚性节点及整体结构的滞回性能和协同工作机理，综合评价结构抗震性能。进而提出混合联肢PEC墙协同工作的力学模型，构建结构整体失效与构件损伤之间的力学关系。基于力学模型，研究耦连比对结构协同工作机理及失效模式的影响规律，给出结构抗震性能的定量评价标准。最终提出地震作用下混合联肢PEC墙结构合理失效模式控制技术，得到结构抗震性能化设计方法。研究成果对提高该结构体系的抗震性能有重要的理论意义和工程应用价值。

结合混合联肢剪力墙结构体系的概念以及型钢部分外包组合剪力墙（PEC剪力墙）抗震性能优异、装配化程度高等优点，提出了一种新型混合联肢PEC墙结构。设计合理的混合联肢PEC墙结构，小震作用下保持弹性，利用抗侧刚度大的PEC墙肢保证结构整体刚度，中震及大震作用下钢连梁首先剪切屈服耗能，然后PEC墙肢底部形成弯曲塑性铰耗能，是一种抗侧刚度大、抗震性能优良的两阶段耗能体系。为全面推进混合联肢PEC墙结构体系在高层、超高层建筑及高烈度抗震设防区的应用，本项目对混合联肢PEC墙结构的抗震性能、协同工作机理以及设计方法展开研究。分别进行了6个梁墙节点、2片3层混合联肢PEC墙2/3缩尺试件拟静力试验，分析其节点及结构整体破坏特征、承载能力及延性、强度和刚度退化、耗能能力及应变分布等。结果表明：弱节点试件的滞回曲线存在一定捏拢现象，后期承载力会出现退化，但抗震耗能能力仍优于普通混凝土联肢剪力墙节点，破坏形态为节点域剪切破坏，表现为节点域范围内型钢腹板屈服，混凝土被斜交叉裂缝分割劈裂并出现剥落。PEC墙肢的引入改善了钢筋混凝土墙肢底部易发生脆性破坏的缺点，显著提高了混合联肢墙结构的抗震性能，整体结构两个试件滞回曲线均呈饱满的梭形，未见明显捏缩现象，正反向位移延性系数平均值基本达到3的位移延性需求，破坏阶段等效粘滞阻尼系数均超过0.3，表现出良好的延性和耗能能力。基于混合联肢PEC墙节点及结构试验结果，采用ABAQUS对混合联肢PEC墙节点及结构进行了多参数分析，探讨了混合联肢PEC墙结构受力机理，建立了混合联肢PEC墙结构承载力计算简化力学分析模型。基于平截面假定，分别给出钢连梁剪切屈服的塑性抗剪承载力计算公式和PEC墙肢五种破坏模式下的极限承载力计算公式。基于性能化设计理念，提出了混合联肢PEC墙结构基于合理失效模式的性能化设计方法。