Research On Mechanical Characteristics Of "Bridge On Bridge" System

The "Bridge on Bridge" system is a common method for bridge reinforcement and temporary improvement of bridge load grade.It has the characteristics of fast erection,easy construction,light,good interchangeability and strong adaptability.It plays an indispensable role in temporary traffic erection such as post-disaster reconstruction and transportation of large goods.But at present,the erection of "Bridge on Bridge" system is mainly empirical,the surplus coefficient is huge,and there is a lack of research on the mechanical characteristics of the calculation formula of "Bridge on Bridge" system.In this paper,we use the derivation formula to solve the precise solution,the finite element numerical simulation to solve the numerical solution,build the experimental model to solve the test solution of three methods,from the "Bridge on Bridge" system of the ultimate bearing capacity,vibration modal analysis,in the mobile load under the operating conditions of the three aspects of the "bridge on bridge" system to study the mechanical characteristics The application of traditional vibration modal detection method and digital image detection method in the detection of the system is also compared.The main work and research results of this paper are as follows:(1)This paper describes the research background,significance and research status and development trend of "bridge on bridge" system at home and abroad.The significance of the "Bridge on Bridge" system in the field of national defense,military,disaster relief and temporary access is pointed out.The inadaptability of the existing calculation method in the calculation of the system is also discussed.(2)The deflection calculation of the "Bridge on Bridge" system about the spacing of the two beams,the main stiffness degree and the structure span is deduced.And Finite element software and experimental model are used to verify the formula respectively.(3)The calculation formulas of deflection of the "Bridge on Bridge" system about the spacing of two beams,the main stiffness degree,the structure span and the concentrated load size are deduced,and the formula is verified by finite element software and experimental model respectively.It is proved that the 1-order vibration type of the "Bridge on Bridge" system is Leung 1-order vibration type and the lower beam is 1-order vibration type.The 2-order vibration type is Leung 1-order vibration type,the lower beam is 2-order vibration type,the 3-order vibration type is Leung 2 order vibration type,the lower beam is 2 order mode,the 4 order mode is Leung is 3 order vibration type,the lower beam is 2 order vibration type,the 5 order vibration type is Leung 3 order vibration type,The lower beam is a 3-order vibration type.(4)This paper expounds the basic principle of video image detection technology,the research status and basic flow at home and abroad,and uses the traditional detection method and image detection technology to compare and analyze the vibration modes of the model,and the research shows that the use of numerical image detection technology is convenient,fast and adaptable under the condition of assurance accuracy.It embodies the superiority of this method in the detection of "Bridge up Bridge" system.(5)The feasibility of strengthening the "Bridge on Bridge" system is verified from three aspects of the system's ultimate bearing capacity,vibration modal performance and dynamic response under moving load conditions.