Study On The Influence Of Construction Fastening Force On The Completed State Of CFST Arch Bridge

The main purpose of construction control of long-span concrete-filled steel tubular arch bridges is to make the bridge alignment and internal force of the structure meet the design requirements as much as possible,and to ensure that the structure is safe and reliable during the construction process.The cable retaining force during construction is not only a guarantee of safety during the construction process,but also one of the influencing factors for the completion status of the CFST arch bridge.Based on the engineering background of Guizhou DaXiaojing Bridge(450m main span concrete-filled CFST truss arch),the theoretical analysis and research on the influence of the cable-staying force on the bridge-filled state of CFST arch bridge is performed.:(1)Extensive review of relevant domestic and foreign literature,introduced the characteristics,development history and superiority of concrete-filled steel tube arch bridges,explained the method of determining the completion status and construction status of arch bridges,and introduced the basic theory of concrete-filled steel tube arch bridges.,Including the basic principles of finite elements,calculation methods of commonly used cable forces,etc.(2)The finite element calculation software BDCMS is used to establish a formal analysis model of the empty steel tube of a large and small bridge.The analysis of the results of the bridge is completed.The linear shape of the designed bridge determined by the one-shot method is used as the goal.The principle of the matrix was used to obtain the sling force during the construction process,and a formal analysis model considering the actual suspension construction process was established.The calculation results of the two during the main construction stages and the bridge completion state were compared.The results show that after considering the construction process The actual bridged state not only satisfies the designed bridged state,but also the internal force state is better.(3)Through analysis and consideration of the bridge formation results under the construction process conditions,it is found that the arch foot section still has a certain negative bending moment,and there is room for optimization.Therefore,the bending moment of the main arch ribs,especially the arch,is minimized as much as possible The foot bending moment is the target.Based on the construction process model,the two sets of cable-holding forces at the front end of the maximum cantilever state are adjusted by trial calculation to further optimize the internal force state of the bridge,and guide the design and construction control of long-span concrete-filled steel tube arch bridges.Certain reference value.