圆钢管约束钢筋混凝土柱—RC梁节点的静力与抗震性能

Tubed RC columns are new kind of composite columns where the RC colums are tubed by thin-walled steel tube and the steel tube bears no axial load directly by disconnecting at the connection. Tubed RC columns evolve from concrete-filled steel tube columns and steel reinforced concrete columns. It is with great prospect of application by combining the advantages of conventional composite columns, including high bearing capacity, excellent seismic and fire resistance performance and conveniently connecting with RC beams. Research on tubed RC structures is focused on the behavior of columns at present, but research on the behavior of beam-column connection has not been investigated in detail. The static and seismic behavior of circular tubed RC column-RC beam connection will be investigated in detail in this research. Failure mechanism, failure modes, bearing capacity and ductility of the composite connections will be investigated by experiment, theoretical analysis and non-linear FEM. Simplified models and axial bearing capacity equations of the connections under axial compression, as well as simplified model and shear strength capacity equations under shear force will be proposed. The hysteretic behavior of the connection will be explicitly identified and the strengthening method of the connection will be proposed. Seismic design suggestions and details will also be proposed based on the research results.

钢管约束钢筋混凝土柱是指在钢筋混凝土柱外设置薄壁钢管，而钢管在节点区断开，不直接承担纵向荷载的一种新型组合柱。钢管约束钢筋混凝土柱是在钢管混凝土和型钢混凝土柱的基础上发展起来的一种框架柱形式，继承了钢管混凝土和型钢混凝土的优点，承载力高，抗震和抗火性能优越，与钢筋混凝土梁连接方便，应用前景广泛。目前，国内外对钢管约束钢筋混凝土柱的研究集中于构件方面，而对梁柱节点力学性能的研究还未系统开展。本项目将对圆钢管约束钢筋混凝土柱-RC梁节点的静力与抗震性能进行系统深入的研究。采用试验研究、理论分析和有限元数值模拟相结合的方法，对钢管约束钢筋混凝土柱-RC梁节点的受力机理、破坏模式、承载力和延性进行研究。建立节点核心区在轴压荷载作用下的简化力学模型和受压承载力公式；建立节点核心区的简化受剪力学模型和受剪承载力公式，明确节点核心区的受剪恢复力特性；提出节点区加强的有效措施，提出抗震设计建议和构造措施。

本项目在国家自然科学基金资助下，对圆钢管约束钢筋混凝土柱-RC梁节点的静力和抗震性能进行了系统的试验研究和理论分析，并按计划完成了预定的目标。项目研究取得的各项成果可为圆钢管约束钢筋混凝土柱-RC梁组合结构的应用和设计提供参考和建议。本项目的主要研究成果如下：.(1).提出了钢管约束钢筋混凝土柱-RC梁框架节点的三种加强措施，包括梁水平加腋、柱节点区并筋和节点区钢管贯通开洞三种形式，对38个节点和8个对比短柱进行了轴压试验研究，研究主要参数包括钢管贯通、加腋、并筋、直交梁等。.(2).根据轴压试验结果，节点区钢管贯通开洞的形式和采用节点区水平加腋提高轴压区有效受压面积的节点形式有优越的力学性能，纵筋并筋的形式可配合前两种节点形式使用。.(3).建立了轴压荷载作用下节点的简化力学模型，并建立了基于ABAQUS有限元软件的分析模型，基于约束机理和局压机理提出了轴压承载力公式和相应设计方法，计算结果与试验及有限元结果吻合较好。.(4).对节点区钢管贯通的节点形式进行了抗震性能试验研究，研究主要参数包括节点形式（中节点和边节点）、轴压比、节点区钢管厚度、节点区焊接钢筋环加劲肋、直交梁和楼板等。