Study On The Construction Control Of The Main Girder Of The Long-span Continuous Rigid Frame Bridge With Unbalanced Side To Center

The structure of prestressed concrete continuous rigid frame bridge combines the structural advantages of T-shaped rigid frame bridge and continuous beam bridge.With this structural advantage,it has been widely used and developed in the field of bridge engineering.During the cantilever pouring construction of continuous rigid frame bridge,due to the structural characteristics,construction characteristics and external environmental factors,the bridge alignment and structural internal force do not meet the design requirements,resulting in construction quality problems during the construction process and after the completion of the bridge,which may lead to serious safety accidents,therefore,it is necessary to strictly monitor the bridge construction.Based on the engineering background of a three span continuous rigid frame bridge(70 + 200 + 70m),this paper studies the construction control and closure of the main beam of the long-span prestressed concrete continuous rigid frame bridge in view of the imbalance of the side and middle span of the bridge.Based on MIDAS civil finite element software,this paper combines the project example,aiming at the key technology of closure construction,namely,the construction of jacking and rigid skeleton,and carries out three-dimensional finite element modeling for the whole bridge and the part of rigid skeleton,and analyzes the construction stage.In the process of research on jacking construction,by considering the calculation and analysis of longitudinal horizontal displacement of main beam,internal force of main beam and internal force of pier under two working conditions of jacking and non jacking,the analysis results of the influence of jacking force on displacement and internal force of bridge structure are obtained and summarized.Based on the local finite element model of the stiff skeleton,the paper analyzes the construction stage of the stiff skeleton,and concludes that the strength and stability of the stiff skeleton meet the requirements,ensure the construction quality of the closure section,and provide the theoretical basis for the smooth closure.This paper introduces the basic theory of bridge construction control,and briefly describes the construction technology of continuous rigid frame bridge.Combined with the project example,the construction monitoring of continuous rigid frame bridge is studied.The main content is linear monitoring and stress monitoring.In view of the unbalanced construction stage of the side and middle span,the monitoring data analysis of the main beam’s linear and stress is carried out.According to the monitoring plan formulated by the monitoring unit,the actual site alignment and stress monitoring methods,processes,contents and control measures shall be formulated.This part is mainly based on the monitoring data of the field monitoring measurement,combined with the theoretical model calculation value to carry out the construction monitoring control of the bridge,so that the alignment and stress meet the design requirements,and finally ensure the smooth closure.