Study On Construction Technology Of Small Cross-section Catwalk Of Long-span Suspension Bridge

The Liujiaxia Bridge belongs to the key project of the Linxia Zheqiao to Grade 2highway.It is designed to cross the Yellow River tributary of the Liujiaxia Reservoir.The completion of the bridge will greatly improve the traffic conditions for ethnic minorities on both sides of the reservoir and further increase the network of the regional road network.And overall efficiency,promote the local economic and trade circulation and the overall development of tourism resources,and improve the living standards of immigrants in the reservoir area is of great significance.After completion,it will also become the longest span suspension bridge in Northwest China.Although catwalks for suspension bridges have been studied in previous constructions,less experience can be drawn from the study of catwalks with small cross-sections in this project.This article passes the design and construction of the Liujiaxia Bridge catwalk.According to the geological and climatic conditions of the project site,the key technologies for the design and construction of small cross-section catwalks are discussed.This article has the following main content:(1)Through the research on the key technologies of continuous catwalk design and construction: designing an economical catwalk based on the combination of the bridge’s physical structure,construction width,construction height,and safety protection.In the construction aspect,a series of safe and applicable construction methods such as pilot cable construction,load-bearing cable erection,cat lane alignment,traction system work,cat lane modification,and cat lane demolition were summarized,which can better guide su bsequent project co nstruction.(2)Establishing a finite element analysis model to study the wind resistance stability of the catwalk.After calculating the steel structure engineering of the catwalk tower gantry,catwalk gantry,load-bearing cable,anchoring system,cable saddle,etc.,the profit of the structure meets the requirements of the code.The minimum safety factor is 3.0,and the structure is safe and reliable.Through the calculation of the static and dynamic wind stability,the results meet the construction requirements,and the overall structure of the Liujiaxia Catwalk System is safe.(3)Through the analysis of the safety and reliability of the catwalk traction system and load-bearing cables,the design and check calculations show that the strength and stiffness stability meets the requirements.The catwalk pull-down device at the bridge tower uses a block instead of a jack tensioning steel rod device.Eliminates the complicated and tedious process of high-altitude operation of the tensioning machine,avoids the replacement of the pressing device and the fixed device,and makes the dynamic adjustment and operation more convenient and safe.The “bracket method” is used to haul catwalk load cables to increase the traction speed.After the catwalk load cables are hauled,the bracket cables are reused as handrail cables.Reusing materials such as steel wire ropes can reduce construction costs.The self-designed and processed steel wire rope retracting and unloading machine is used to unwind and recover the steel wire rope for catwalks,which improves the operation efficiency and the protection of the steel wire rope.This technology has obtained the national utility model patent authorization.Through the successful design and implementation of the catwalk of the Liujiaxia Bridge,the catwalk design and construction mentioned in the article can provide reference and reference for subsequent projects.