Construction Control Of Concrete Filled Steel Tubural Arch Bridge And Tension Control

The concrete filled steel tubular arch bridge is a kind of bridge structure which combines the beam and the arch organically.The structure system has been rising in our country in recent years.In the process of construction,the problems such as the alignment and the internal force of the main beam,temperature stress of steel pipe during concrete placement and cable force of suspender need to be controlled by establishing a suitable construction monitoring system.This paper takes the 64 M tied arch bridge crossing the Tongsan highway in Mu village as engineering background.Combined with the existing theory and method of construction monitoring,collecting and analyzing the date of the state of the bridge in the construction stage is to ensure that the bridge alignment,stress and suspender cable force meet the specification requirements.The main contents are as follows:(1)The Doctor Bridge is used to carry out the finite element modeling of the whole bridge,and the cumulative displacement of main girder and arch rib is obtained.The reliability of the model is verified by comparing the calculated results with the design data.In the process of construction,the parameters of the model are adjusted according to the material test and the measured data in order to improve the control precision.(2)The adaptive degree method is used to monitor the bridge.To identify the main parameters of the bridge by using the least square method,and the various stages of bridge deformation prediction,combined with the finite element model of girder and arch rib are pre camber,determine the vertical mold elevation,the alignment of the bridge into the ideal.(3)This paper analyzes the factors affecting the stress control in the construction control,and discusses the influence of temperature and shrinkage and creep.Based on the theory of shrinkage and creep,the non stress strain in the measured strain is separated.The results of stress testing are obtained which are closer to the actual stress.(4)MIDAS/FEA finite element software is used to simulate the concrete filled steel tubular arch ribs.The hydration heat released in the process of concrete pouring and the influence on the steel tube arch rib are analyzed.Result shows that during the pouring process of concrete filled steel tubular arch,a large amount of hydration heat is released, which has the characteristics of temperature field of mass concrete.(5)The cable force of suspender directly affects the stress state of the whole bridge,so it is very important to identify the suspender cable force.By comparison and analysis,the suitable practical formula is selected to identify the suspender cable force of the bridge.The influence matrix method is used to precisely adjust the suspender of the bridge,and the cable force error is less than 5%.This proves the validity of the influence matrix method.