Joint Stiffness Of Cold-formed Steel Yurt And Its Influence On Internal Force And Sidesway Of Structure

Cold-formed steel is widely used in housing construction because of its green and environmental protection,good seismic performance and easy industrial production and processing.This paper uses theoretical analysis combined with numerical simulation to analyze the cold-formed steel beam-column inclined nodes and column foot nodes to provide a theoretical basis for the design of such nodes and the analysis of rigid frame forces.With reference to the component method of European Code(EC3),the initial rotational stiffness calculation model of cold-formed steel beam column inclined node and column foot node is proposed,and the influence of beam node bolts and node plate deformation on the rotational stiffness of beam column inclined node and column foot node,and the influence of column foot node bolts,column foot node plate deformation and column foot base plate deformation on the stiffness of column foot node are considered respectively,and the initial rotational stiffness theory of cold-formed steel beam column inclined node and column foot node is derived.This theoretical method complements the study of semi-rigid nodes of cold-formed steel.A numerical model was established to analyze the mechanical properties of cold-formed steel column foot nodes.A horizontal load is applied to the column foot node,and the node damage stress cloud,moment-turn angle curve and initial rotation stiffness are obtained by changing 18 factors affecting the node.The results show that the node load capacity and initial stiffness increase with the increase of C-section steel thickness and node plate thickness;the increase of base plate thickness can effectively improve the node load capacity;the base plate bolt diameter and column bolt diameter have less influence on the node performance.The nodal stiffness of the column foot within the parameters of this paper is 1800～2300 k N-m/rad.Combined with the conclusion of the research on the cold-formed steel beam-column inclined node in the early stage of the group,the Lin theory analysis and numerical calculation results of the two nodes are compared,and the average error is found to be 3.6% and 3.12%respectively,and the theoretical formula has high accuracy.By applying static load to cold-formed steel plane rigid frame,the effect of different nodal stiffness on internal force of rigid frame is obtained,and combined with Pushover analysis of cold-formed steel plane rigid frame and yurt rigid frame,it is found that the increase of nodal stiffness can effectively improve the lateral resistance and overall stiffness of the structure,and the semi-rigid nodal rigid frame has good seismic performance.The research results of this paper lay the foundation for the application of cold-formed steel nodes in engineering,and can also provide reference basis for the design of engineering.