内管加强型中空夹层钢管混凝土柱-钢梁节点抗震机理与设计方法研究

Concrete-filled double skin steel tube(CFDST) columns is the component that consist of two concentric steel tubes with sandwich concrete between them. CFDST has much good performance, such as light weight, good anti - seismic, unfolding cross-section, high flexural stiffness and so on. The difference between CFDST and the CFST is how to transfer the force to the inner steel tube reliably. A new type of joint with concise and specific transmission path, high stiffness, high bearing capacity and convenient construction is proposed, which named circular or square CFDST columns and steel beam joints with reinforced inner tube and ring stiffeners. By means of experimental research, finite element modelling and theoretical analysis, the bearing capacity of the joint is determined and the joint is optimized by studying the static behavior of the joint. Then the seismic behavior and design technique of the joint are systematically studied, including the effect of axial compression ratio, hole rate of cross section, type of ribs and other parameters on the seismic behavior of joints, the force-transmission mechanism of the joint, the moment-rotation hysteretic model, the shear-shear deformation model in core area, the degradation of ductility, energy dissipation, strength and stiffness, and the proper joint construction. The research team has already completed the scientific study of circular and square CFDST columns under the various action of single load, compound load and reciprocating load, which laid a theoretical foundation for the research to smoothly carry out.

中空夹层钢管混凝土是在同心放置的内外两层钢管间灌注混凝土而成的构件，具有自重轻、抗震性能好、截面开展、抗弯刚度大等优点。中空夹层钢管混凝土与实心钢管混凝土节点的区别在于如何将力传递给内钢管，课题组提出了一种传力路径简洁明确、节点刚度大、承载力高、施工方便的新型节点——内管加强型圆、方中空夹层钢管混凝土柱-钢梁加强环式节点。拟采用实验研究、有限元模拟和理论分析的方法，通过对节点静力性能的研究确定截面类型、空心率和加肋形式对节点工作机理的影响，再对新型节点的抗震机理和设计方法进行系统的研究，包括：多种参数对节点抗震性能的影响，节点的传力机理，节点抗弯和抗剪承载力计算方法，荷载-位移滞回模型，延性，耗能，刚度退化及合理的节点构造。课题组已完成对圆、方中空夹层钢管混凝土柱在各种单一、复合受力及往复荷载作用下的系统研究，这为该研究的顺利开展奠定了理论基础。

中空夹层钢管混凝土柱是在同心放置的内外两层钢管间灌注混凝土而成的构件，具有自重轻 、抗震性能好、截面开展、抗弯刚度大等优点。本项目提出了一种传力路径简洁明确、节点刚度大、承载力 高、施工方便的新型节点——内管加强型圆、方中空夹层钢管混凝土柱-钢梁加强环式节点。 并采用实验研究、有限元模拟和理论分析的方法，对此类新型节点的抗震机理和设计方法进行系统的研究。.(1)对17个内管加肋型圆（方）套圆中空夹层钢管混凝土柱-钢梁节点进行低周往复试验。分析了节点试件在往复荷载下的强度退化、刚度退化、节点延性和节点的耗能能力等得到相关规律。试验结果表明，各试件滞回曲线均较为饱满，没有出现捏拢现象，呈梭形，表现出良好的耗能能力。.(2)采用ABAQUS有限元软件上建立此类节点模型，根据钢管混凝土、钢梁等不同材料的性质，分别引入相对应的本构关系，通过设置各种材料间的接触来模拟框架结构中各个部件组合的方式，设置合适的边界条件与加载方式，将计算得到的有限元分析结果与试验结果相比较，二者较为吻合。有限元模拟验证滞回曲线与单调曲线拟合良好，可以通过单调荷载下节点受力情况进而研究其各项性能。.(3)对节点在肋长、肋宽、空心率、轴压比、梁柱抗弯承载力之比、混凝土强度等参数变化下的节点的荷载-位移关系曲线、弯矩-转角曲线和剪力-剪应变曲线进行了系统分析，确定节点抗震性能的影响参数。.(4)对节点的受力机理进行了详细的分析，研究了在加载过程中特征点的外钢管、核心混凝土、内钢管和钢梁的应力状态。.(5)通过调用abaqus的python接口，实现了参数化自动建模以及由滞回曲线提取出骨架曲线、强度退化、刚度退化、耗能数据的插件。对参数化功能模块进行黑盒验证测试并分析验证结果，可以看出所开发出的参数化建模插件和后处理插件程序是可以实现所需的建模和数据处理功能。