钢-混凝土组合空间框架拟动力有限元分析

基于混凝土的塑性-损伤本构模型与钢材的弹塑性混合强化本构模型，采用ABAQUS有限元分析软件，对圆钢管混凝土柱-钢筋混凝土框架梁2层空间框架的三维实体精细有限元模型进行拟动力分析。模型中考虑了钢管与核心混凝土的约束作用以及连续地震作用下引起的塑性耗能累积效应。对钢管混凝土柱轴压比、钢管横向变形系数以及各关键点的钢管与核心混凝土、框架梁、环梁与楼板中的钢筋和混凝土的应力-应变滞回曲线以及框架结构的塑性耗能分布情况进行分析。结果表明：连续工况地震作用使框架结构产生塑性耗能累积效应，进而使楼层的位移响应明显增大，层间刚度减小；连续工况地震作用后，钢管和所有钢筋都屈服，钢管、环梁钢筋的约束作用使核心混凝土、环梁混凝土强度超过其轴心抗压强度，楼板混凝土因受拉而开裂；短边柱的轴压比有明显波动，罕遇地震作用下其值大于角柱、中柱和长边柱的轴压比；钢管混凝土柱为主要的塑性耗能构件，环梁次之。

Finite element analysis for pseudo-dynamic behavior of steel-concrete composite space frame

Based on the plastic-damage constitutive model of concrete and elasto-plastic mixed hardening constitutive model of steel, finite element software ABAQUS was used to build an elaborate 3D solid finite element model and perform pseudo-dynamic analysis of a two-story space frame with circular concrete-filled tubular (CFT) columns and RC frame beams. The model considers the confinement effect of the steel tube on the core concrete and the cumulative effect of the plastic energy dissipation caused by the continuous earthquake action. Further calculation was conducted on axial compression ratio of CFT columns, lateral deformation coefficient of steel tube, stress-strain hysteresis curves and plastic energy dissipations of the steel tube, the core concrete, as well as the rebar and concrete of RC frame beam, ring beam and floor slab. The results show that: because of the accumulative effect of plastic energy dissipation from pseudo dynamic test under continuous cases, the displacement of the floor is increased and the story stiffness is decreased significantly; after the seismic action of continuous cases, all the steel tube and rebar yield, the strength of the core concrete and the ring beam concrete exceeds its axial compressive strength due to the confinement effect of the steel tube and rebar. Besides, the concrete of floor slab cracks because of tension; the axial compression ratio of the CFT columns on the short side varies with time and exceeds those of corner columns, interior columns and columns on the long side under rare earthquake; the CFT columns are the main plastic energy dissipation members, followed by the ring beams.