Research On Model Correction Method Based On Response Surface And Its Application In Evaluation Of Bridge Bearing Capacity

Due to the importance of bridge structure and its own structural characteristics,bridge finite element model modification has become one of the research hotspots in the field of civil engineering.Combined with the advantages and disadvantages of various finite element model correction methods,the joint static and dynamic finite element model correction method based on response surface is favored.However,how to select suitable weight coefficients to better integrate static and dynamic information remains to be solved.In order to avoid the subjectivity of simple weighted processing or empirical evaluation,this paper proposes a new joint static and dynamic method based on response surface model modification on the basis of the traditional joint static and dynamic method,i.e.a new joint static and dynamic method which integrates various objective functions of different residuals into a single objective function through adaptive weighted combination,and realizes the weight distribution of each single objective function through genetic algorithm.Taking “Xiazhongba Jialing River Bridge” as the engineering background,the new combined static and dynamic method based on response surface model modification is used to modify the finite element model of the bridge.Finally,the modified finite element model is applied to the bearing capacity evaluation of the bridge.The main contents and conclusions of this paper are as follows:1.The implementation steps of the finite element model updating method for bridge structures based on response surface are described concisely,and the construction of response surface model is introduced in detail.In the construction of the objective function of the model updating method,an adaptive weighted combination method is used to construct the single objective function of the combined dynamic and static forces.2.Taking a numerical simply supported beam with simulated damage as an example.The objective function of “measured value” and response surface model is constructed by adaptive weighted combination method,and the genetic algorithm is used to calculate and optimize the objective function.The results of optimization are very close to the true value of damage,which verifies the feasibility and reliability of the adaptive weighted combination method based on response surface model updating technique.3.Based on the static and dynamic load test data of “Xiazhongba Jialing River Bridge”,the measured frequency and deflection of the test are taken as the target responses,and the initial finite element model of the bridge is modified by a new combined static and dynamic method based on response surface model modification.Through verification,a benchmark finite element model which can be used for further research or engineering application is obtained.4.Based on the benchmark finite element model of “Xiazhongba Jialing River Bridge”,the equivalent calibration coefficient was used to verify the measuring points that failed to collect the measured strain values in the static load test of the bridge,and the evaluation of the bridge bearing capacity by the static load test was successfully completed.