| With the continuous improvement of China’s transportation infrastructure construction,bridge engineering across deep ravines,rivers and seas has also greatly developed.Suspension bridges are widely used in domestic construction of long-span bridge construction schemes due to their strong spanning ability,good adaptability,and attractive appearance.Due to the complex environment of the bridge location in the southern waters of China,the in-service suspension bridge is greatly affected by the deep-sea environment,the structural members are seriously corroded,and the heavy-load traffic is restricted.Suspension bridges in service usually need to replace the slings and improve the protection system to maintain the safe operation of the structure to meet the growing traffic volume and adapt to the changing atmospheric environment.Through analysis and research on the replacement method and bearing capacity of the sling replacement process of the suspension bridge,it will be of great significance to the development of the cable bearing system bridge in the coastal area.In this paper,by consulting a large number of literatures,relying on the service conditions of the slings and protection systems of the Humen Bridge,combining the cable finite element simulation model to calculate the cable line shape,simulating the replacement scheme of the slings,and compare the cable replacement scheme of Jiangyin Bridge,and get the structure and protection system of replacement of anchor plate and sling.This article focuses on the following areas:(1)Based on reading domestic and foreign literature,grasp the current development status of the suspension bridge,the current status of disease research,and the development of reinforcement technology,and summarize the current research status.(2)The structural calculation theory and load-bearing capacity calculation method of suspension bridge are introduced,and the calculation method suitable for the replacement(failure)of suspension cable is obtained through analysis.(3)Based on the nonlinear analysis theory of the suspension bridge,the nonlinear effects of the suspension bridge in the case of sling replacement are analyzed,and the influence of the sling replacement on the bridge alignment and other factors based on BNLAS is clarified.The results show that the sling exchange has a great impact on the local area,and the main cable will not have excessive deformation.Therefore,the analysis of the sling exchange can be used for the nonlinear analysis in the initial bridge formation state,and the results can meet the needs of the project.(4)According to the structural form and span layout of the bridge,the finite element software Bnlas,Midas,and Ansys were used to accurately simulate the cable structure of the bridge structure,stiffening beams,and temporary anchor points.Under the condition of ensuring the safety of the slings,a new lifting point and a temporary cable work together to form a multi-lifting point replacement scheme.According to the actual situation of the bridge structure,the analysis and comparison of the sling replacement sequence was carried out with the goal of not interrupting traffic and reducing construction time on the site.Based on this basis,the world ’s first anchor plate sling replacement scheme without interrupting traffic was proposed.(5)Combined with the bridge structure itself and external factors such as climate environment,operation conditions,etc.,the main factors that cause the rust of the sling are analyzed.The new protection system,new components and structural details are adopted to ensure the life of the sling from the source,thereby ensure the operational safety of the structure during the design basis period. |
