Model Updating Of Chongqing ShiBanpo Yangtze River Double Line Bridge Based On Static And Dynamic Method

During the life cycle of bridge structure the actual state of its static and dynamic response values is an issue which is always attended by engineering research field. Estimating responses by finite element program is an efficient method and has advantages which are low cost and high speed. But due to every kind of reduction and assumption, the static and dynamic responses which are estimated by the bridge's initial finite element model established with the design drawings often have differences compared with the test results. Therefore, it is an important research direction provided with crucial theoretical and practical value that how to update the initial finite element model and make calculated values approach actual responses of the structure, and the updating technique and results can have application in structure for static and dynamic response analysis, damage identification, health monitoring, and safety assessment and so on.Grounded on ShiBanpo yangtze river double line bridge, this paper brings forward an updating method that makes use of the universal finite element program and the maths program, and verify its feasibility by numerical simulation, also this method will be used to update finite element models of the bridge. The main works as follows:①On the foundation of elaborating the existing model updating methods, this paper brings forward a finite element model updating method which is based on sensibility analysis and SQP algorithm: first, model parameters which need updating are selected according to engineering experiences and sensibility analysis results; then the updating objective function that contains the structure responses,the parameter and its sensibility values is constructed; at last, it is assumed that the sensibility value of parameters remain constant in minor range, and the parameter updating is transformed to a series of subproblems. This method not only cuts down the workload greatly through availably combining the universal finite element program with the maths program, but also conveniently and easily carries out the model updating of large structures.②The finite element model of ShiBanpo Yangtze river double line bridge is established, and the relationship of parameters and some uncertain factors in modeling is discussed.③By means of numerical simulating, that whether the parameters can be updated to approach the assumed"actual value"is checked by the model updating method of this paper. The results of simulation indicate that well updating results can be gained through three times of solving for subproblems, and it also indicates that the model updating method brought by this paper is feasible and practical.④The numerical model is updated by the dynamic model updating method, and the simulated results are compared with the ones that gained through the method brought by this paper, the compared results display that the latter method is well.⑤The load test is done for the ShiBanpo bridge before it is operating, and the initial finite element model of the bridge is updated with the method put forward by this paper, after that the updated model is gained at last. The static and dynamic responses calculated by the updated model are even more consistent with the test values than that calculated by the initial model.