Modeling and model updating of cable-stayed bridge based on measured frequency and cable tension

摘要

Modeling method of important component of cable-stayed bridge, modeling by simulating the construction process, ascertaining initial balance position of model, updating model parameters based on measured data, are the key problem in modeling process of cable-stayed bridge. Based on Binzhou cable-stayed bridge, parametric modeling by ANSYS was implemented considering joint stiffening of beam, deck and tower, nonideal boundary condition and grading load. Construction process was simulated by the function of element birth and death in ANSYS. Adjustment process of cable tension was simulated by way of applying temperature load. Cable tension of model was adjusted based on ideal balance position and measured cable tension. The mass parameter of bridge deck was adjusted based on measured cable tension. A function was formed to be approximation of mapping relationship between parameters to be adjusted and model frequency, so the use of ANSYS during optimization process was avoided and optimization efficiency was improved greatly. The range of parameter was ascertained and parameters value was adjusted applying improved Genetic Algorithms. The result show that above method was introduced considering general factors, the efficiency of model updating Algorithm is very high, the model parameters updated is reasonable, the cable tension and frequency is almost equal to that of real bridge, and the model can represent the real bridge in main mechanical behavior. So this method is worthy to application.