型钢增强节点钢管约束钢筋混凝土柱框架结构地震损伤控制与设计方法研究

Aiming at the current situation that joints of steel tubed reinforced concrete (STRC) column frame structures are relatively weak, the reinforcing scheme using embedded steel in joints is put forward in this applying program, and based on the principle of structural damage mechanism control and the idea of seismic performance design, STRC column frame structural systems with steel reinforced joints are studied systematically through theoretical analysis, experimental research and numerical simulation. Firstly, the hysteretic behavior and plastic hinge formation of STRC frame columns with non-penetrating steel are explored, and methods to evaluate seismic shear capacity based on ductility demand and design embedded steel are established. Secondly, the shear failure mechanism and performance of STRC joints reinforced by steel are discussed, and the methods to calculate shear compression ratio and mathematical model of shear capacity are developed. Thirdly, the overall seismic performance of STRC column frame structures with steel reinforced joints is assessed, and the restoring force model and evolution law of different levels of damage are determined; and meanwhile, the criterion to discriminate different damage mechanisms and condition to attain a beam plastic hinge mechanism are identified. Based on above, seismic damage performance levels and quantifying indexes for this type of frame structures are studied, on which the method to achieve the desired seismic performance objectives for a given level of design earthquake is proposed, and the seismic design method of structural systems based on damage mechanism control is established finally. The research results will provide the theoretical foundation and science support for improving the seismic performance as well as for facilitating the application of frames made from STRC columns with steel reinforced joints.

针对钢管约束钢筋混凝土（STRC）柱框架节点较为薄弱的现状，提出采用内置型钢增强的构造方案，基于损伤机制控制原理和抗震性能设计理念，对型钢增强节点STRC柱框架结构体系展开深入研究。拟通过理论分析、试验研究和数值模拟，确定内置非贯通型钢STRC框架柱的滞回特性和塑性铰形成机制，建立柱基于延性需求的抗震受剪承载力计算和型钢配置的设计方法；研究型钢增强STRC柱框架节点受剪破坏机理和性能，建立节点核心区的剪压比限值和受剪承载力计算模型；研究型钢增强节点STRC柱框架结构的整体抗震性能，确定其恢复力模型和多层次地震损伤演化规律，提出各损伤机制的判别准则及梁铰机制的实现条件；研究型钢增强节点STRC柱框架结构地震损伤性能水准和量化指标，建立结构在设计地震作用下性能目标的控制方法，提出其基于损伤机制控制的抗震设计方法。研究成果为提高STRC柱框架结构的抗震性能、推广其工程应用提供理论依据和科学支撑。

本项目瞄准高层建筑研究前沿，通过理论分析、模型试验和数值模拟，对型钢增强节点钢管约束钢筋混凝土（STRC）柱框架结构的地震损伤控制与设计方法展开深入研究。首先，提出一种内置型钢增强STRC柱节点的构造形式，针对节点中的内置非贯通型钢STRC柱，采用低周反复荷载试验研究其破坏模式、损伤演化和协同工作机理，明确了柱塑性铰形成机制，分析了轴压比和型钢长度对柱抗震性能的影响，建立了不同破坏形态下柱压弯承载力计算模型，提出非贯通型钢配置的设计方法。其次，明确内置型钢对STRC柱框架节点的抗剪增强机理，基于薄膜元理论在混凝土项中引入软化系数，建立了考虑型钢长度影响的腹板主应力计算公式，提出了内置型钢增强STRC柱节点抗剪承载力计算模型。结果表明：内置非贯通型钢STRC柱均发生压弯破坏，所有试件在加载后期仍具有稳定的承载能力；型钢长度较短时其抗弯性能不易发挥，增大长度可明显提升试件抗震性能，当长度超过一定值后，型钢增强作用趋于稳定；柱底部钢管主要提供横向约束作用，中部钢管主要参与截面抗弯；所提框架柱及节点承载力计算模型具有较高的精度和较小的离散性，可供实际工程参考。再次，分析了强节点系数和柱梁抗弯承载力比等对型钢增强STRC柱梁组合件抗震性能的影响，明确了组合件损伤机制与其设计参数的关系，建立了组合件梁铰机制的实现条件，分析了各非线性变形在组合件层间位移中所占比例及变化规律，基于修正的塑性铰长度及截面曲率计算公式，建立了内置型钢增强STRC柱梁组合件的弹塑性变形计算模型。最后，建立了考虑型钢增强节点影响的STRC柱框架结构精细化数值分析模型，确定了结构的地震损伤和耗能机制，揭示了构件、楼层到整体结构损伤之间的演化规律，提出了结构体系基于损伤控制的性能水准和抗震性能评估方法，分析表明，所提方法计算结果精确，可为结构抗震设计提供新的思路。项目研究成果对提升此类新型结构的抗震性能和推广应用具有重要的意义。