Reasonable Bridge State To Determine The Self-anchored Suspension And Sling Tension Optimization Study

In rencent years, self-anchored suspension bridge has drawn more and more attraction among the engineering for its merits such as graceful appearance, great flexibility and satisfactory economic features and so on. At the same time, it has also brought many problems in design and construction because its mechanical characteristics are different from land-anchored suspension bridge. The key issues of design are determination of the rational completion status and hanger tensioning procedure.With the help of a large finite element calculation and analysis program, MIDAS/CIVIL, this dissertation proceeds the study on determining the rational completion status and optimization of hanger tensioning for self-anchored suspension bridges. Based on the Foshan Pingsheng Bridge, work done and major research results achieved in this paper are as follows:(1) This dissertation summarizes the development of self-anchored suspension bridge, characteristics, research status, static calculation and optimization theory of hanger tension.(2) A step-by-step method of determining the rational completion status is proposed in this dissertation. The method has three steps. a) The force of the hangers is preliminarily determined with least bending energy method. Then, the irrational force should be adjusted. b) Take the bridge structure as study objects. The completion force status of the bridge structure will be obtained after the non-linear iteration calculation. Based on this, the moment envelope can be gotten with the linearization method of finite displacement. c) With internal force balance method to establish the feasible region of the live load moment for bridge completion status inspection. The rational completion status should satisfy the feasible region of the moment for the bridge.(3) Take Foshan Pingsheng self-anchored suspension bridge for example, the rational completion status of this bridge is determined with this step-by-step method mentioned above.(4) Based on the rational completion status, an optimization method of hanger tensioning is proposed in this dissertation. In this method, the divided tensioning technique is controlled by the unstrained length of the hanger and the jacking force. Take Foshan Pingsheng self-anchored suspension bridge for example, three hanger tensioning scheme are calculated with backward construction step analysis. The optimal hanger tensioning scheme is determined through comparing the feasibility, safety and efficiency of the schemes at length.