Finite Element Model Updating Of Taiping Lake Bridge Based On Kriging Model

In order to realize the health monitoring,damage identification and condition assessment of the bridge structure to ensure its operation safety within the design life,it's essential to establish a baseline finite element model that meets the engineering accuracy requirements and reflects the structural mechanical properties.Due to the complexity of the structure,many simplifications and assumptions in the modelling and numerous uncertainties in the analysis process,the initial finite element model needs further updating so that the distinction between the theoretical prediction and the measured results can be within allowable range.The updated model canplay the role of predictive evaluation better.The updating process of the finite element model not only needs to satisfy the correspondence between the theoretical results and the measured results,but also the modified parameters must be guaranteed to have a clear physical meaning.In this paper,based on the engineering background of a concrete cable-stayed bridge with single tower and single cable plane,using the Kriging model,the implicit function relationship between the bridge structure parameters and the structural response is established.The optimization iteration process is completed in the Kriging model without substituting in the finite element model.The calculation process is simple and clear.Based on the measured data of the health monitoring system installed on the bridge,the initial finite element model established based on the drawings is updated finally.The main research work and conclusions of the paper are as follows:1.First,the Kriging model and corresponding parameters determination method are introduced.The specific process of applying the Kriging model to update the structural finite element model is given.A numerical example was used to compare the updating results of the Kriging model with the results of polynomial function response surface using fewer sample points.The results show that the Kriging model fits better than the polymomial response surface when the number of sample points is small,which can be employed well to complete the model updating.2.The initial finite element model of Taiping Lake Bridge was established based on the design drawings.The vibration acceleration data of the structural health monitoring system was extracted and the modal parameters were identified.Through comparison,it is found that the first-order natural frequency error of the initial finite element model exceeds 18%,so it is necessary to update the initial finite element model.Through the sensitivity analysis,the structural parameters to be updated are selected,and the uniform design test design method is used to establish the Kriging model and perform the optimization algorithm.The results show that the natural frequency value of the updated finite element model is very close to the actual measurement result,and the updated parameter value also complies with the interpretation of the physical reference values of the Taiping Lake Bridge.3.Calculate the stress values at the critical cross sections using the finite element model before and after updating,and the importance and necessity of the finite element model updating in engineering application are verified.