Construction Procedure Optimization Of Self-anchored Prestressed Concrete Suspension Bridge

Self-anchored prestressed concrete (PC) suspension bridge, on account of its pleasant appearance, great flexibility and satisfactory economic features, has been rapidly applied in China. As this type of bridge is newly developed domestically in recent years, there are few references with respect to this structure, and there are fewer literatures regarding its construction. Self-anchored suspension bridge is different from ordinary suspension bridge with ground anchorage. Due to the special formation of main cable which is anchored on strengthening girder, the loads on girder is different from those on ordinary suspension bridge with ground anchorage, and their construction sequences are completely opposite with each other. As for the construction of a self-anchored suspension bridge, strengthening girder construction shall be finished before main cable erection, which is usually cast on raft support scaffold. After erection of main cable and suspender, the suspenders are usually tensioned in several steps and the restriction of scaffold is then gradually released. Scaffold release procedure is always a difficult problem I the construction of self-anchored PC suspension bridge.On the basis of domestic and oversea researches, this paper, by means of theoretical analysis and technical comparison, has made penetrating analysis and comparison on the aspects main cable deformation, vertical deflection and stress of strengthening girder as well as tension in suspender after scaffold dismantlement, specifically:The sequence of scaffold dismantlement in self-anchored PC suspension bridge construction that has great affect on the alignments of main cable and strengthening girder and deflection of pylon, is a key component in construction control. The objective of this study is to reach the feasible bridge completion status after falsework dismantlement. According to different dismantlement schemes applicable for self-anchored PC suspension bridge, FEM mode is used to simulate different release procedure, and analyze the loading conditions of strengthening girder, main cable and suspender after release of scaffold under different construction scheme, and then by means of comparison, the optimal construction scaffold dismantlement sequence applicable for self-anchored PC suspension bridge is obtained.This thesis generally involves in following work:1) It narrates the analysis theory and approach of self-anchored PC suspension bridge.2) It makes description on construction mechanics and construction control of self-anchored PC suspension bridge.3) It, by means of FEM program and among different construction plans, makes analysis and comparison on a sample self-anchored PC suspension bridge, i.e. the Xiaohuanghe Self-anchored PC Suspension Bridge at Xinxian County, and finally figures out the optimal construction sequence.4) On the basis of bridge construction monitoring work, the feasibility and reliability of construction sequence is checked theoretically and practically.