Study On The Assessment Method Of Bearing Capacity Of Bridges Based On Dynamic Measurements

At present,the number of highway bridges in our country has exceeded 800,000.Bridge detection and monitoring technology is the key to ensure the normal use and safety of active bridges.The theory and method of bridge assessment are the core problems that need to be solved.As we know,static load test method is the traditional method to evaluate the bearing capacity of existing bridges.But it has some problems,such as closed traffic,long test period,high cost and low efficiency.However,it is more simple,faster and more efficient to evaluate the bridge bearing capacity by using dynamic test method than static load test method,which can effectively compensate the above-mentioned shortcomings.But there are still no effective evaluation theories and methods for the evaluation of bridge carrying capacity by using dynamic method.In order to solve this problem,two methods of evaluating the bearing capacity of bridges based on dynamic test are studied and put forward by theoretical analysis and experimental verification.According to the calculation method of static load deflection check coefficient and the physical meaning of flexibility,this paper presents a method of evaluating the bearing capacit y of bridge based on dynamic measurement frequency and flexibility.By using Abaqus finite element software,the static and dynamic numerical analysis of a reinforced concrete beam will be carried out.The modal parameters of the structure are obtained by using the Eigensystem Realization Algorithm(ERA).Then the frequency calibration coefficient and the flexibility check coefficient are calculated and compared with the corresponding static load deflection check coefficients respectively.The feasibility o f the two methods to evaluate the bearing capacity of the bridge is discussed.In this paper,two kinds of dynamic evaluation methods proposed above are used to carry on the static and dynamic numerical analysis of a downstroke steel arch bridge with special-shaped by using Midas Civil software.The applicability of these two dynamic methods to the evaluation of arch bridge and the similarities and differences between the two dynamic methods are studied.The feasibility of the evaluation method of bridge bearing capacity based on dynamic test in practical engineering application is studied by static load and dynamic test of the laboratory scale model of Binzhou Yellow River Bridge in Shandong Province.