Stiffness analysis of the joint suitable for partial double-layer reticulated shell integrally formed by post-tensioning

This paper analyzes the forming process of a K6-type partial double layer reticulated spherical shell by post-tensioning.By tensioning the steel wire in the bottom chords which are insufficient,the plane space truss can be arched and transformed to reticulated spherical shell progressively.By research on the influence of the joint connection types on forming post-tension force and forming initial stress,the features which the joint should have are summarized.On the basis of the analysis above,this paper develops a new applicable joint.Finite element software is used for joint analysis to obtain the moment-rotation curves of the processes before and after welding.It is proved that this joint could meet the demand of increasing joint stiffness with certain measures.The influence of some basic parameters on the stiffness of the joint is also studied and the reasons of variation tendency and influence degree of joint stiffness are discussed.The computing formula of joint stiffness by the method of regression analysis is finally obtained.