Construction Supervision And Analysis Of Prestressed Concrete Box Girder Top Pushing On Cross Railway

In recent years,with the rapid development of China’s transportation industry,bridge engineering construction has achieved rapid development.With the increasingly advanced technology,new design ideas,convenient construction,cost-saving bridge structure construction technology constantly emerge.The jacking construction method has been widely used in the field of bridge structure construction due to its many advantages,such as light simplicity,strong applicability of special site,no requirement for foundation and clearance under bridge,factory construction and easy quality management.With the continuous improvement of new materials,new technologies and new processes,the application range of pushing technology has been expanded,and good economic benefits have been obtained.However,due to the particularity of the prestressed concrete box girder jacking construction method,such as pushing the construction of the beam at the stress state change is bigger,the construction stress state and operating condition are also more,pushing more technical risks existing in the construction process,therefore in the process of pushing the construction of the girder stress,displacement and safety factors such as temporary pier horizontal displacement change real-time monitoring.Strengthening the construction supervision of the top push of prestressed concrete box girder and the safety of auxiliary structure are helpful to the smooth construction of the bridge structure.Therefore,this paper mainly studies the safety monitoring and analysis of the overthrust construction of the span railway prestressed concrete box girder bridge.Based on the project of the cross-pingqi railway and the separate interchange between nantong expressway and nenjiang bridge,this paper carries out the construction monitoring and research of the cross-railway prestressed concrete box girder top pushing construction.The main work of this paper is as follows:First,based on the actual bridge structure of this project and the main load parameters during the construction process of the span railway prestressed concrete box girder bridge,the measuring points of stress and displacement in the construction process are reasonably arranged to determine a complete and efficient monitoring plan.Secondly,the finite element model of the top push structure and the key construction process of the prestressed concrete box girder bridge is established based on the actual construction process and construction stage,and the simulation calculation is conducted.Finally,on the basis of the finite element model,the theoretical values of stress and deformation monitoring of the beam body during the jacking construction are obtained first,and the theoretical values of stress change curve monitoring are obtained through data analysis.The temporary piers in the jacking stage are calculated and analyzed.The precamber curve of the structure is determined by the finite element program.It provides theoretical data support for the construction monitoring of the bridge,and provides reference for the safe and smooth implementation of similar cross-railway prestressed concrete box girder top pushing construction projects.