Analysis Of Construction Control Theory And Arrangement Of Construction Control System For Single-tower Hybrid Girder Cable-stayed Bridge

The main girder of the hybrid girder cable-stayed Bridge with arch main tower is composed of concrete and steel structure.The combination of concrete box girder and steel box girder can not only improve the mechanical characteristics of the structure,but also has better economy,at the same time,the arch-shaped Pylon also has good mechanical performance and aesthetic effect,which makes the arch-shaped Pylon Hybrid Beam cable-stayed bridge widely used in modern cable-stayed bridge construction.Cable-stayed bridge is a highly statically indeterminate structure,and construction loads and live loads have a great influence on the stability of the structure.In order to keep the whole structure in a reasonable linear and stressed state in the construction stage,the completion stage and the service stage,the theoretical calculation of the whole structure and the monitoring of its construction process complement each other and can not be dispensed with.In this paper,the whole construction process of Jiangwan bridge on Qujiang road in Shaoguan is monitored and the calculation models of the bridge are established by using BDCMS and Midas/civil.The research contents of this paper are as follows:(1)The calculation results of stress and deformation of the structure in construction stage and completion stage are analyzed theoretically,the results of cable force calculated by monitoring and control are compared with the results of cable force in the construction stage and the reasons for the deviation are analyzed.The main calculation results of the structure under live load and combined load(dead load and live load)are analyzed.(2)Sensitivity analysis is carried out for the relevant parameters such as cable force,steel box girder dead weight and concrete bulk weight of Jiangwan Bridge.By increasing the cable tension value by 5%,10%and 15%,the influences on the stress and deformation of the main beam and tower are analyzed respectively.The influence of steel box girder’s dead weight on the cross section stress and deformation of main girder and main tower was analyzed by increasing the dead weight of steel box girder by 2%,4%and 6%successively.The influence of concrete bulk density increasing by 5%on the stress of main girder,main tower and cable force of the completed bridge is analyzed.The analysis results have certain reference value for determining the reasonable cable force of the completed bridge and the reasonable line shape of the main girder.(3)The construction monitoring scheme and the establishment of the monitoring system in Jiangwan Bridge are briefly summarized.The strain,temperature and settlement of the main tower were monitored on site,and the measured values were compared with the theoretical values.The problems were found and feedback in time to ensure the smooth construction process,it has certain guiding significance for the actual construction process.