Construction Control Of Shenyang Gaokan Bridge

Self-anchored suspension bridges are more and more admired by engineers fortheir advantages such as beautiful appearance, clear force, strong spanning ability andhigh adaptability to the geology. Especially, it has become a more competitive designscheme during the construction of small and medium-span bridges in cities in recentyears. However, if we do not carry out rigorous monitoring during the process of thebridge construction, self-anchored suspension bridges will not get security guaranteesbecause of its complicated structure, long construction period and high constructionhazard. Therefore, the construction control is essential when building bridges. Thispaper studies the theory and method of the construction control of self-anchoredsuspension bridges based on Shenyang Gaokan Bridge construction control. The maincontent includes the following several aspects:Analyze the calculation theory and method about the main cable configuration ofcompleted bridge, deduce the process of calculating the main cable configuration ofcompleted bridge and the free length of each main cable by segmental catenary theory,and the free main cable configuration is also calculated according to constant free lengthprinciple. Analyze the influence of factors such as main girder length change, maintower length change and temperature change to the main cable erection configuration,and the construction precision is enhanced.According to the characteristic of Gaokan Bridge and considering the influence offactors such as the number of tension, the order of tension and the number of extensionbars to the hanger tension process, the reasonable state of removing the frameworkaway and hanger tension scheme are determined by the finite element program.According to proposed construction control scheme, the main girder configuration,the main cable configuration, the main tower deviation, the main girder and main towerstress and the hanger force are measured during the hanger tensioning process. And theyare measured after each hanger tension in detail, the result should be compared with thecalculation result in order to direct the next tension. As soon as all the framework getout of the main girder, the hanger force should be adjusted reasonable in order to ensurethe construction safety and the overall structure of the whole bridge.In view of the hanger force measurement in the process of hanger tension, based onthe string theory and the influence of factors such as the bending stiffness and thebounding conditions to the natural frequency, the relational expression of the hanger force and the natural frequency under fixed on both ends of the beam model is deduced.And comparing the hanger force respectively from the frequency method and the oilpressure gauge, the expression precision is tested and verified.