Research On Construction Control Technology Of Large Span Double Tower Steel-concrete Composite Beam Cable-stayed Bridge

Cable-stayed bridges in the form of steel-concrete composite beams can give full play to the properties of composite materials,meet the needs of larger spans,and have the advantages of comfortable driving and beautiful appearance.It has become the main structural form of current cable-stayed bridges.However,the construction process of a long-span steel-concrete composite beam cable-stayed bridge is complicated and there are many influencing factors.How to ensure that the completed state of the bridge meets the design requirements,the main bridge is straight and smooth,and the structural stress is reasonable?It has become the focus in this type of bridge construction process.This paper focused on the research of construction technology and construction control of long-span steel-concrete composite beam cable-stayed bridge.The completed work and content are as follows:(1)First,this study introduced the development overview of steel-concrete composite beam cable-stayed bridges and bridge construction control,the existing problems and the significance of carrying out construction control research.At the same time,it briefly introduced the calculation methods and related theories that need to be used in construction control technology.The subsequent research lays the theoretical foundation.(2)Then we introduced the engineering background of the construction control research in this article,collected the required parameters in various aspects,and carried out the wet joint concrete material test and the steel-concrete composite beam structure beam-slab synergistic performance real bridge test according to the characteristics of the background project.We also developed a new type of micro-expansion concrete to be applied to the wet joints of the bridge,and obtained the law of stress and strain changes in the wet joints and the law of cooperative work between beams and slabs,and provided more accurate data parameters for the subsequent establishment of the full bridge finite element simulation model,which reflect the force state and deformation law of the main bridge under different working conditions.(3)Subsequently,this paper established the finite element simulation model of the main bridge,and carried out structural simulation analysis and calculation at the same time,analyzed the stress,deformation,prestress and cable force change law of the key structure of the bridge in various working conditions,combined with the measured data,formed a monitoring Instructions to guide subsequent construction.At the same time,it introduced the related work content of on-site construction control,and made necessary explanations on the arrangement of the instrument,the measurement time and period,and the calculation method of the original data.The data collected on site was fed back to the model in time,so that the simulation analysis could be better optimized.(4)Finally,this article focused on analyzing and studying the sensitivity of key structures to different factors,distinguishing between the main influencing factors and the secondary influencing factors.On this basis,gray theory and BP neural network prediction methods were selected to predict the deflection of the main girder.We came to the conclusion that the most suitable prediction method for this bridge is the BP neural network prediction method,which was applied to the construction control of a long-span steel-concrete composite beam cable-stayed bridge,and a good control effect has been achieved.Through the analysis and summary of the construction control results of the bridge,the alignment,stress and cable force were well controlled,and the construction control work was very successful.This method indeed has certain reference and application value.