Analysis of the influence of combined joint stiffness on the seismic performance of combined frame

Combined framework;  combined node stiffness;  self-oscillation period;  layer displacement;  Underlying shear

In order to study the influence of the stiffness of the steel-concrete composite joint on the seismic performance of the composite frame, the stiffness of the composite joint and its influencing factors are discussed firstly, and then through a multi-layer steel structure engineering example, Ansys finite element software is used to establish the pure steel frame and the composite frame, and four frame models are assumed to be rigidly connected and the joint stiffness is considered, and the multi-encounter seismic response spectrum analysis and elastic time history analysis are carried out, and the calculation and comparison are carried out. The calculation results show that after considering the combined effect of the steel frame, the overall self-oscillation period of the structure becomes shorter and the basic self-oscillation period is reduced by 4.13%, indicating that the overall stiffness of the structure becomes larger. However, after considering the joint stiffness, the seismic period increased, the basic self-vibration period of the pure steel frame and the composite frame increased by 4%, the corresponding seismic displacement became larger, and the layer displacement of the response spectrum analysis terms of the two models increased by 17% and 2%, respectively, indicating that the combined joint stiffness is a non-negligible factor on the seismic performance of the structure.