球节点刚度对单层柱面网壳地震响应影响随 PGA 变化的规律

Effects of Spherical Joint Stiffness on Seismic Response of Single-Layer Cylindrical Reticulated Shell Changing with Peak Ground Acceleration

已有研究发现单层柱面网壳焊接空心球节点刚度对结构的地震响应有一定影响,为了解此影响随PGA(地震动峰值加速度)变化的规律,对相同尺寸的单层柱面网壳精细化模型和常用模型进行了地震响应对比分析。其中精细化模型是按照空心球节点和钢管杆件的实际尺寸建立的壳单元模型;常用模型采用梁单元建模,不考虑球节点。改变PGA后,对比2种模型相同位置节点的位移时程曲线可以看到:随着PGA的增加,精细化模型与常用模型的节点位移响应差值越来越大;PGA超过结构的失稳临界值后,随着PGA的增加,加大精细化模型节点壁厚对提高结构抗失稳能力的作用越来越小。

The previous studies find that the hollow spherical joint stiffness has a certain influence on seismic response of single-layer cylindrical reticulated shell .In order to analyze the rule of this influence with PGA （peak ground acceleration） changing ,two types of finite element models are built .The two types of models have the same size except the spherical joint .The first type is a fine model built by shell element and its spherical joints and tubes are built by considering the real size ;the other type is the common model w hich is built by beam element ,and the spherical joints are neglected .Comparing with the seismic response of the two types of models when PGA changes ,the results show the difference between the two types of model in node displacement-time curves is increased as PGA increases ;w hen the PGA is larger than the collapse acceleration of structure , the influence of increasing joint wall thickness on improving the structural capacity of anti-stability is decreased as PGA increases .