Finite Element Model Modification And Mechanical Condition Evaluation Of Cable-stayed Bridge Based On Load Test

Cable-stayed bridge is one of the preferred bridge types for large-span bridges.China is also the country with the largest number of cable-stayed bridges in the world.After the cable-stayed bridge has been in operation for many years,there will be some changes in its internal force state and the internal force state at the time of completion.Especially when designing cable-stayed bridges,it is necessary to understand the actual static and dynamic characteristics of the structure as the basis for cable replacement.A finite element model that can reflect the actual condition of the bridge is needed.Due to various assumptions and simplifications in the modeling process,the static response and dynamic characteristics of the initial finite element model of the cable-stayed bridge based on the design drawings are not the same as the test results.Therefore,by revising the initial finite element model so that its theoretical calculated value tends to the true response value of the structure,it has become an important theoretical and practical research direction.Among them,the modification of the finite element model of the cable-stayed bridge based on load test is an important way.Taking a cable-stayed bridge as the engineering background,this paper proposes a model modification method that combines load testing with large-scale general finite element analysis software ANSYS.The feasibility of this optimization method is verified by numerical simulation and applied to actual engineering Finite element model correction.The main work completed and the conclusions reached include:Firstly,a finite element model modification method combining static response and dynamic characteristics is proposed.Establish a full-bridge finite element model based on the design drawings,combine engineering experience and sensitivity analysis results to select the parameters to be corrected as design variables,construct the design variables and optimize the objective function between the sensitivity value and the structural response value of the structural response Error range,the modified model and parameter values are obtained through optimization algorithms.Secondly,the feasibility of the correction method is verified by numerical simulation.The objective function of the static response and dynamic characteristics of the load test conditions and the error of the test measured value is modified to verify whether the corrected parameter value can approach the minimum error The value is artificially given,and the revised parameter value is used to verify the other two working conditions of the numerical simulation test.The results show that the proposed finite element model modification method based on static response and dynamic characteristics can complete the numerical model modification well.Finally,carried out the application research of the solid cable-stayed bridge project based on the load test to modify the finite element model.According to the load test test results of the cable-stayed bridge,the initial finite element model of the bridge was modified using the model correction method proposed in this paper that combines the measured static response and dynamic characteristic values.The results show that the calculated value of the initial finite element model after correction is closer to the test value than before the correction.The modified finite element model of the cable-stayed bridge can be used as the static and dynamic response analysis,damage identification,safety assessment and health monitoring of the structure,and as the benchmark model for the cable-changing design of the cable-stayed bridge.