Mechanical Analysis And Monitoring For Construction Of A 96m Simply-supported Steel Truss Erected With Rotation And Translation Method

In recent years,with the rapid development of railway construction in China,railway lines are more and more intensive.It is seen that two or more lines may meet at a junction.And the situations that a new railway crosses or runs parallel to the existing railway line occur frequently.The bridge of Lushan railway station is a new bridge along Ruichang-Jiujiang railway line.It is a 96 m long simply-supported steel truss which crosses the Wuhan-Jiujiang railway.In order to keep the normal operation of the existing railway line below,the construction process of the bridge is:(1)The whole structure of the bridge was first assembled near the designed bridge site,(2)It was moved to the bridge site by both the rotation and translation method.The aim of this thesis is to study the rotation and translation construction method by the 96 m simply-supported steel truss girder bridge near Lushan railway station.For the construction process,the mechanical models of temporary support pier,slipway-beam and steel truss girder were established by mechanical analysis.In the finite element models,the temporary support pier and steel truss girder were simulated by three-dimensional beam element,and box slipway-beams consisted of steel plates were simulated by three-dimensional shell element.Then the finite element method was used to analyze the stress and deformation status of the steel truss girder and the supported structures in all load-cases during the whole construction process.Consequently,based on the computed results of stress field,a reinforcement scheme was proposed for the slipway-beam where the local buckling or insufficient intensity may occur under dangerous working conditions.Furthermore,some stress sensors were fixed on the steel truss girder and the supported structures.The real-time monitoring for the steel truss girder has been carried out to observe the big stresses and displacements of the structures during the construction process.The measured values of the working stresses of the structures also showed that all the structures are safe in the construction process.Thus,the mechanical analysis and monitoring of whole process not only ensured the safety of the bridge construction with the rotation and translation,but also made the final stress state and deformation of the finished bridge meet the design requirements.The method of the mechanical analysis and monitoring for the bridge erected with rotation and translation method can be referred for other similar bridge constructions.