Research On Preventive Maintenance Method Of Long-span Steel-concrete Composite Beam Cable-stayed Bridge

The rapid development of China’s transportation industry has increased the number of long-span steel-concrete composite beam cable-stayed bridges that are put into construction and use,and the importance of such bridges in the transportation system has become increasingly prominent.The operation and maintenance level of steel-concrete composite beam cable-stayed bridges is related to the service level and service life of the bridge.Therefore,it is China’s due meaning in the process of developing from a bridge power to a bridge power.At present,most of the research results on the preventive maintenance of bridge structures are difficult to be directly and effectively applied to the preventive maintenance of specific steel-concrete composite girder cable-stayed bridges with complex structures.Therefore,the preventive maintenance of steel-concrete composite girder cable-stayed bridges is still facing great deficiencies in China.Carrying out preventive maintenance for steelconcrete composite beam cable-stayed bridges can effectively improve the problems existing in traditional bridge maintenance,and achieve the maintenance purposes of reducing maintenance costs,improving the level of structural service status and extending the service life of bridges.In this paper,based on the structural characteristics of steel-concrete composite beam cable-stayed bridge,starting from the mechanism of disease occurrence,combined with the basic theories of preventive maintenance at home and abroad,the preventive maintenance technology of the steel-concrete composite beam cable-stayed bridge was studied.First,by analyzing and sorting out the disease occurrence mechanism of each component of the steelconcrete composite beam cable-stayed bridge,the main influencing factors that cause specific diseases were found out,and a theoretical basis was provided for determining targeted maintenance measures;Secondly,in view of the large volume of large-span steel-concrete composite beam cable-stayed bridges,in order to ensure to enhance the detection of important components and areas in the daily maintenance of bridges,the importance based on the generalized structural stiffness was used to evaluate and analyse the importance of stay cable and steel-concrete composite beams in various regions of the entire bridge.Based on the results of the importance analysis,the center of gravity of the maintenance work of the steelconcrete composite beam cable-stayed bridge was determined,thereby improving the efficiency of the maintenance work;Thirdly,the cost and effect of preventive maintenance of bridges are closely related to the selection of preventive maintenance timing.In order to maximize the benefits of preventive maintenance investment of bridges,based on existing prediction methods of bridge component performance degradation,an structural degradation prediction method that can be easy to use and has good prediction accuracy was selected to determine preventive maintenance timing of typical components of steel-concrete composite beam cable-stayed bridge,thereby the preventive maintenance of steel-concrete composite beam cable-stayed bridges achieves optimal efficiency;Finally,on the basis of the determined specific maintenance measures and methods for the specific diseases of each component of the steel-concrete composite beam cable-stayed bridge,the preventive maintenance system of steel-concrete composite beam cable-stayed bridge with complete organization structure,a comprehensive database,and scientific and reasonable human resource management is established.