Study Of Disease Analysis And Demolition Technology Of Huayudong Truss Composite Arch Bridge

Truss composite arch bridge began in the late 1970 s,the first one was built in Guizhou in 1981.Its feature has light structure,it uses less material and investment.Therefore,it is widely used in the whole country.With the rapid development of our national economy,the traffic volume increases rapidly and the number of heavy-duty vehicles increases as well.In addition,there are some other comprehensive reasons,such as the aging of materials,the low design standard,the original bridge design is not all reasonable,and the quality of construction is on the low side,which has causes the crack,the downward deflection,the member breaks and so on the diseases appeared.It affects the bridge and the traveling safety.Huayudong bridge is a composite arch bridge with a main span of 150 m,which is affected by many factors,such as defect of bridge type,heavy traffic volume and heavy traffic and so on.The upper truss structure of Huayudong bridge was seriously damaged.Therefore,we have decided to demolish and rebuild the bridge at its original site.Through the comparison of several schemes,finally the new-built concrete-filled steel tube arch bridge is been chosen as the temporary support for the original bridge demolition,and the cable system for the installation of the steel tube arch rib is used to the demolition and reconstruction of the composite arch bridge of Huayudong.Up to now,there is no construction precedent in China.Therefore,this paper takes Huayudong bridge on G320 line as the research object,and it carries out the following research work:Firstly,it based on the test results of Huayudong bridge,the cause of disease was being analyzed.Combined with the characteristics of disease of Huayudong bridge,the cause is being analyzed from the structure and construction method of truss composite arch bridge.Secondly,according to the design and construction of Huayudong bridge,and the geographical environment condition.After a comparative study,it carries out blasting demolition method,arch frame demolition method and cable hoisting demolition method.To aim at the requirements of Hongfeng lake as first one-level water source,it was proposed to use the newly-built concrete-filled steel tube arch to demolish the original bridge;Finally,it based on the scheme of bridge dismantling,and established the space model of truss composite arch bridge,concrete-filled steel tube arch bridge and temporary suspension cable as one model.With the analysis of numerical of the process of bridge dismantling,the main focus is on the scheme of arch opening of truss composite arch and the technical requirements of arch opening.To combine with the analysis results,there is a set of demolishing scheme of Huayudong bridge is proposed to meet the construction safety,and compiled the technical requirements Huayudong bridge.The research results show that to use the newly-built concrete-filled steel tube arch as temporary support in the dismantling stage of truss composite arch is feasible.It also given the corresponding technical requirements,which provide a new technology for non-blasting demolition of arch bridge.At the same time,it accumulates some experience for similar bridge demolition.