环梁式圆钢管约束H型钢混凝土柱-钢梁节点的抗震性能

Seismic Behavior of Circular Steel Tube-Confined H-Steel Reinforced Concrete Column-Steel Frame Ring Beam Joint

设计了一种环梁式圆钢管约束H型钢混凝土柱-钢梁节点,并建立了该试件的全尺寸三维有限元分析模型,计算得到了此类节点试件的滞回曲线、骨架曲线及破坏模式,经与试验结果进行对比,两者吻合良好.在此基础上,对试件进行有限元变参数分析,考察了轴压比、混凝土强度、梁柱线刚度等对试件抗震受力性能的影响,同时提出了一种改进型梁端削弱翼缘的节点形式.结果表明:随轴压比增大,试件的耗能及延性性能明显下降;混凝土强度的变化对试件滞回性能影响不大;当保持柱截面不变,仅变换钢梁尺寸时,节点的承载力、延性及抗震耗能性能均随梁-柱线刚度比的增大而显著增大;而当保持钢梁截面不变,仅改变柱内型钢含钢率时,节点抗震受力性能随梁-柱线刚度比的变化并不明显;改进的梁端翼缘削弱形式的试件可在不明显降低其承载力及耗能性能的情况下,将塑性铰外移至距节点区较远的地方,从而更好地保护节点区.上述研究结论可为此类新型节点的应用提供理论基础.

In this paper,a circular steel tube-confined H-steel reinforced concrete column-steel frame ring beam joint was designed,and a full-scale three-dimension finite element analysis model of the specimen was established.Then,the hysteretic curves,skeleton curves and failure modes of the specimens were calculated,and the results were compared with those obtained by experiments,with good accordance being found.Moreover,a finite-element variable parameter analysis was carried out to reveal the effects of axial compression ratio,concrete strength and line stiffness ratio on the seismic behavior of specimens.Finally,an improved node form of beam end-weakening flange was put forward.The results show that(1)with the increase of axial compression ratio,the energy dissipation and ductility of the specimen decrease significantly;(2)the change of concrete strength has little effect on the hysteretic behavior of specimens;(3)the bearing capacity,ductility and seismic energy dissipation performance of the joints all increase significantly with the increase of beam-column linear stiffness ratio when the column section remains unchanged and only the steel beam size varies;(4)when the section of steel beam remains unchanged and the steel content in the column varies,the change of seismic behavior of the joint with the line stiffness ratio of beam to column is not obvious;and(5)the adoptin of beam end-weakening flange helps to move the plastic hinge far away from the joint area without remarkably reducing the bearing capacity and energy dissipation performance of the specimen,thus protecting the joint area more effectively.The above-mentioned relevant conclusions lay a theoretical foundation for the application of this new type of joint.