钢管混凝土柱-钢梁外加强环螺栓连接节点抗震性能有限元分析

Finite element analysis of seismic performance of concrete-filled steel tubular column-steel beam with external reinforcement ring bolted joint

为深入研究钢管混凝土柱-钢梁外加强环螺栓连接节点的抗震性能,建立了螺栓连接节点的精细化三维实体有限元模型。在对已有试验成果进行验证分析的基础上,研究加劲肋、螺栓连接数量对节点塑性耗能分配机制的影响。结果表明:当钢材本构后期考虑韧性损伤后,有限元计算结果与已有拟静力试验结果更吻合;CFST-1节点(梁高300 mm,有螺栓垫板)耗能能力最优,但仅达到相应焊接节点的一半;与CFST-1节点相比,CFST-3节点(梁高300 mm,无螺栓垫板)及CFST-2节点(梁高250 mm,有螺栓垫板)的总耗能更低;各螺栓节点的塑性耗能分配机制主要依靠梁耗能,而相应的加强环焊接节点主要依靠梁与加强环耗能;当螺栓节点采用环板加劲肋、4排螺栓以及腹板加劲肋构造优化后,刚度、承载力、延性与相应焊接节点一致,总塑性耗能达到刚接节点的79.1%,基本达到刚接节点的抗震水平。

In order to study the seismic performance of the bolted joints of concrete-filled steel tubular column-steel beam with external reinforcement ring bolted joint,a refined three-dimensional solid finite element model of the bolted joint was established,and the influence of the number of stiffening ribs and bolted joints on the plastic energy dissipation mechanism of the joints was investigated on the basis of verifying and analyzing the existing experimental results.The results show that when the ductile damage is considered in the late stage of the steel structure,the finite element calculation results are in better match with the existing static test results.The CFST-1 joint(beam height is 300 mm and with bolt spacer)has the best energy consumption capacity compared to the corresponding welded joint,but only up to half,and the CFST-3 joint(beam height is 300 mm and without bolt spacer)and the CFST-2 joint(beam height is 250 mm and with bolt spacer)have a lower total energy consumption compared to the CFST-1 joint.The plastic energy distribution mechanism of each bolt joint mainly relies on beam energy dissipation,while the corresponding reinforcement ring welding joint mainly relies on beam and reinforcement ring energy dissipation.When the bolt joint adopts ring plate stiffening ribs,4 rows of bolts and web stiffening ribs,the stiffness,bearing capacity and ductility are consistent with the corresponding welded joint,and the total plastic energy dissipation reaches 79.1%of that of the rigid joint,which basically reaches the seismic level of the rigid joint.