Application of the Combination of Levenberg-Marquart with Gauss-Newton in Static Parameter Identification of Bridge Structure

Now, the methods used to identify the service bridge structure static parameters are mostly Levenberg-Marquardt algorithm and Gauss-Newton algorithin. However, the singular iterative matrix and harsh terms of initial value can£§t be overcome in Gauss-Newton algorithm.While using Levenberg-Marquardt algorithm can meliorate the Gauss-Newton algorithm, the identification result from Levenberg-Marquardt algorithin is rough. Therefore, the new method has been put forward, in which the result of Levenberg-Marquardt algorithin used firstly is regarded as the initial value of Gauss-Newton algorithin.The precision of the identification will be improved by using this method. In order to validate the method, numerical simulative test on a continuous beam with three spans has been carried out. Using the method, the precision of identification is 2 times higher than that using Levenberg-Marquardt algorithin.The result indicates that using the method can guarantee the reliability of strucrue parameters. Then the quantitative and reliable message can be put forward for structural condition assessment.