新型约束钢管高强混凝土组合柱的破坏机理研究

High strength concrete encased CFST composite columns with high strength steel tube and high strength stirrups (hereinafter called as new type high strength concrete encased CFST composite columns) can not only solve the key technical problems of poor seismic performance and node complex structure on the traditional concrete encased CFST composite columns used in high-rise and heavy load buildings, but also promote the application of high strength and high performance material to achieve the purpose of energy conservation and environmental protection. Therefore, the popularization and application of this new type composite column has notable economic and social benefit. Through the methods of combining test research and finite element simulation as well as theoretical analysis, the failure mechanism and compression behavior of this new type composite column will be studied. Meanwhile, the reasonable matching relationship of high strength steel tube and high strength stirrups to high strength concrete, and the calculation theory of ultimate bearing capacity and stiffness will also be proposed. The seismic damage mechanism, horizontal bearing capacity, stiffness degradation, ductility, energy dissipation capacity and other nonlinear behavior of this new type composite column will be analyzed detailedly under the action of earthquake. This research project mainly discusses the influence of failure mechanism on the double constraint under combined high strength steel tube and high strength stirrups, and proposes the design calculation theory of horizontal bearing capacity, axial compression ratio limit value, stirrup level limit, steel tube area ratio and confinement index, etc. Research results can provide the scientific basis for the engineering application of this new type structure system.

高强箍筋约束高强钢管高强混凝土组合柱（以下简称“新型约束钢管高强混凝土组合柱”）的提出及推广应用，不仅能解决高层重载建筑中传统钢管混凝土组合柱的抗震性能不理想、节点复杂等关键技术问题，还可以促进高强高性能材料的应用，节能环保，具有显著的经济效益和社会效益。本项目通过试验研究、有限元方法和理论分析，研究新型约束钢管高强混凝土组合柱的受压力学性能和破坏机理，建立高强箍筋、高强钢管和高强混凝土的合理匹配关系，提出组合柱受压强度和刚度计算理论；研究该新型约束钢管高强混凝土组合柱的地震损伤机理、承载力、刚度退化、延性以及耗能能力等性能，建立非线性有限元模型进行参数分析，重点考察高强箍筋和高强钢管双重约束对组合柱破坏机理的影响，提出组合柱水平承载力设计计算理论，给出保证组合柱延性的轴压比限值、配箍水平限值、钢管面积比、套箍指标等的确定方法及建议值。研究成果可为该新型结构体系的工程应用提供科学依据。

为了解决高层超高层建筑中传统钢管混凝土组合柱的抗震性能不理想、节点复杂等关键问题，促进高强高性能材料的应用，为此本项目研究不同约束情况下钢管高强混凝土组合柱（以下简称“新型约束钢管高强混凝土组合柱”）的破坏机理及受力性能。主要研究成果包括：对高强混凝土标准试块和钢管高强混凝土柱进行试验，研究了高强混凝土力学性能及其与钢管界面黏结性能；完成了一些列新型约束钢管高强混凝土组合柱试件的轴压、压弯、压弯剪性能试验，变化参数有箍筋强度及配箍形式、钢管截面尺寸、偏心距、长细比（剪跨比）、加载制度、轴压比等，重点考察不同受力状态下新型约束钢管高强混凝土组合柱的内力分布、破坏形态、承载力、刚度退化、变形能力等性能；试验基础上进行理论分析，全面深入地揭示新型约束钢管高强混凝土组合柱各受力状态下的破坏机理，确定钢管、箍筋与高强混凝土的匹配关系，建立理论模型，提出了能够反映钢管影响的刚度和承载力计算理论及实用设计方法，建立了能够考虑加载制度影响的双参数地震损伤模型和恢复力模型，给出了有关的构造措施及设计建议。研究成果可为该新型结构体系的工程应用提供科学依据。