The Research On Joint And Suitable Joint Stiffness Of Partial Double-Layer Barrel-Vault Reticulated Shell Integral Formed By Post-tensioning

Reticulated shell which is integral formed by post-tensioning is a new kind ofspace structure system, and an innovation of prestressed technology in space structurebuilding field. The principle of this structure system is：the original system issingle-chorded plane space truss, with some shorter bottom chords which havetensioning steel wires in them；by tensioning the steel wires, the gaps between thebottom chords are closed, and the plane space truss turns to space reticulated shell.This new type of space structure system introduces the prestressed technology into theprocess of reticulated shell construction, makes sure of that the assembly andtensioning processes of reticulated shell can be done on the ground, and uses out-planeweb members to improve the integral stability of the formed structure. This structuresystem has good application prospect, but there are still many key problem lack inresearching and to be solved.For the purpose of promoting the engineering practical of this system, we usefinite element software Abaqus6.10as the tool, on the basis of predecessors’ research,choose a square planar rectangular pyramid grid plane space truss as the initialtensioning model to research the joint applicability of the partial double-layerbarrel-vault reticulated shell integral formed by post-tensioning, and further developthe applicable new joint. In the study of joints’ applicability, this article mainly focuses on two aspects：theinfluence of joints connection types to the shell forming shape and forming initialstress. Using the method of shortening the bottom chords by negative temperature tosimulate the tensioning process, contrasting several space truss models with differentjoint connection, and considering the influence of geometric nonlinearity and materialnonlinearity at the same time. Analysis results show that：the stiffness of jointconnection influenced both the forming shape and forming initial stress of reticulatedshell integral formed by post-tensioning, and shared the same changing trend, but theimpact on forming initial stress was much bigger than that on forming shape；theconnection between joints and upper chords, which had the same direction withtensioning, had the biggest impact in all connections. Consulting the predecessors’research on the loading capacity of partial double-layer barrel-vault reticulated shell,we summarize the features which the joint should have to need the demands of twoprocesses.In the study of joints’ stiffness, this article first develops a new type ofhinge-to-rigid hollow ball joint on the purpose of engineering application, according todemands of the system. This joint meets the demand of low stiffness of tensioningprocess by constructing one-direction hinge. After forming, weld several connectedplates to meet the demand of increasing stiffness in loading process. Finite elementsimulation analysis is carried out on the joint entities, the results show that：this newhinge-to-rigid hollow ball joint could meet the demands of the joint stiffness in twoprocesses of the reticulated shell；the connection strength of the bar welding plates hadthe biggest influence on the rotation stiffness after reinforcement of the joint. Based onthe results of analysis, we use quadratic orthogonal linear polynomial to do theregression analysis on joint stiffness, then come out the reference regression formula.At the last, summarize the research of this article, and prospect the developmentof reticulated shell formed by post-tensioning in the future.