Research On Shape Forming Process And Load Behaviors Of Post-tensioned And Shaped Barrel-vault

The post-tensioned and shaped space trusses is a new space structural system. Compared with the traditional space trusses,the assembly of the new space trusses can be finished wholly at ground level and it improves validly the stability behavior of single-layer shells because of the use of out-of plane web members,so the new space structural system will have the important advantage in the future application.Based on the research on the post-tensioned and shaped barrel-vault,a single-chorded plane space truss formed barrel-vault with post-tension is used in this paper,through nonlinear finite element analysis,the shape forming process and load behaviors is studied.The paper mainly does work as follows:Though simulating the shape forming process of post-tensioned and shaped barrel-vault by nonlinear finite element analysis,the joint connections in the traditional single-chorded plane space truss as well as the forming shape of barrel-vault are studied.It lays a theoretical foundation for the building of ideal model.A single-chorded plane space truss finite element model of post-tensioned and shaped barrel-vault is established and the finite element analysis and simulation on the shape forming and ultimate load are carried out.Results indicate that the single-chorded plane space truss model in this paper has very good deformability and it can form dome with more rise-to-span ratio by means of a post-tensioning technique, the forming shape of barrel-vault can be controlled by the gaps which are given in certain bottom chords.The post-tensioning forces and member forces produced in the shape forming process are small and the bending stress is much larger in comparison with the axial stress in the member forces.The post-tensioned and shaped single-chorded barrel-vault has satisfactory ultimate load capacity.Then the analysis and simulation using various finite element models with geometry,and material nonlinear taken into account is carried out on a set of influencing factors,such as the stiffness of joint connections,the post-tensioning forces,the member forces produced in the shape forming process,etc.Some useful conclusions are drawn from computer modeling.In the finite element analysis,the factors affecting the shape forming process of barrel-vault,such as the hinge of the web member at the top-chord joints,can be taken into account.A whole and continuous analysis method which is put forward by Dr.Liu is used for reference,for solving the question of applying the member forces produced in the shape forming process to the finite element models of load analysis.The nonlinear stability of single-chorded barrel-vault is preliminarily studied and the buckling model and ultimate load of the barrel-vault under the various load forms are analyzed.Last,the overall conclusion is drawn and the prospect of future study is also listed.