The Technology Of Virtual-actual Combination And The Model Test For The Construction Control Of Cable-stayed Bridge

Compared with ordinary bridges,the construction process of cable-stayed bridge is complicated and the external disturbance is large.It is a strong coupling in the design and construction.Therefore,it is very important to choose the appropriate construction method and develop a reasonable monitoring scheme for the bridge alignment and structural stress.Cantilever erection is the most widely used construction method of cable-stayed bridge.However,under the influence of various factors in the construction process,the internal force and deformation of the structure are more complex.In order to meet the design requirements,the construction control is very important to ensure the final alignment and stress state.The traditional bridge cantilever construction control method is time-consuming and laborious,the degree of automation is not high.Therefore,it is difficult to achieve the desired construction control effect.On the basis of the traditional construction control method,this paper puts forward the technical thought of the “Virtual-Actual Combination” construction control.This technology is based on the powerful image processing function and the virtual simulation function of the system in Matlab,that is,digital image edge detection technology and virtual reality technology.Finally,the feasibility of the construction control technology of the "Virtual-Actual Combination" is verified by the example of the laboratory self-machining cable-stayed bridge.The main research contents and results in this paper are as follows:(1)The principle and realization method of digital image detection technology are introduced in detail.At the same time,the advantages of the method are compared with the traditional measurement methods,and it is successfully applied to the identification of thedisplacement of the cantilever erection of cable-stayed bridges.Compared with the identification results and the theoretical data,and the trend is basically the same.(2)The virtual reality technology is studied systematically.The virtual reality simulation model is established by the virtual reality modeling language VRML,and the simulation model is simulated by Simulink dynamic simulation modeling language.The measured results and the theoretical results are imported into the virtual simulation environment,which vividly shows the difference between them.Through the parameter sensitivity analysis to determine the main design parameters,and then the finite element model is modified to get the accurate and reasonable data of cable-stayed bridge deformation,which provides an effective reference for the construction control.(3)Based on digital image detection technology,VRML virtual modeling technology,Simulink dynamic simulation technology and finite element analysis technology,this paper puts forward the technical thought of the “Virtual-Actual Combination” construction control,which bases on the traditional construction control method.It is applied in the construction control of the cantilever erection of a cable-stayed bridge,and the ideal control effect is obtained.The results show that the “Virtual-Actual Combination” construction control of the initial exploration of the better results,and it provides some theoretical reference value for the future application of the technology to the actual bridge construction monitoring.The practice has showed that: based on digital image processing technology and virtual reality technology,which the technical thought of the “Virtual-Actual Combination”construction control is reasonable and effective.It can visually show the error between the measured results and the theoretical results in each stage of the construction control.At the same time,the error between the two can be solved in time.As well as,it has a high degree of automation and information,which provides an effective construction control method for the actual bridge construction control in the future.