Finite Element Model Updating Research Of Combined Cable-Stayed Suspension Bridges

Based on the finite element theory, the finite element model of the bridge structure can be built according to the design drawings. However, as a result of the model structure error, model parameter error and model order error, the model can’t reflect the actual working state of the bridge structure, it means that some error exists between the finite element model and the actual structure, resulting in that the computing response of the finite element model and the measured response of the structure can not match well. To ensure that the calculation results of the finite element model can truly reflect the actual bridge structure, modification should be made for the finite element model.Along with the development and construction requirements of the bridge in China, the combined cable-stayed suspension bridge will be more competitive in the design of large span bridges in the future, the research of the corresponding health monitoring system is being carried out. Finite element model updating is an indispensable process to establish intelligent bridge health monitoring system, so the finite element model updating research of combined cable-stayed suspension bridges is necessary. In addition, the finite element model updating research of combined cable-stayed suspension bridges can also provide a reference for the finite element model updating research on the other types of bridge.The main work accomplished in this paper, including:Firstly, the current research of finite element model updating at home and abroad are reviewed, some common model modification methods are simply introduced, The advantages and disadvantages of these methods are analyzed, ultimately the response surface method is chosen as the finite element model updating method in this paper.Secondly, the theory of the response surface method is introduced, the steps and implementation process of the finite element model updating based on the response surface method is given, the basic knowledge and its realization process of the sequential quadratic programming method and genetic algorithm method is introduced, which is used to solve this constraint optimization problem.Thirdly, the stiffening girder connection and damage simulation of one combined cable-stayed suspension bridge is researched, to lay the foundation of the research on model modification and damage identification.Finally, the initial finite element model of the bridge’s two damage condition is established according to the design drawings, the finite element model updating of the combined cable-stayed suspension bridge is accomplished, according to the measured response of bridge structure based on the model test. Results show that after the modification, the computing response of the finite element model and the measured response of the structure can match well.