Study on Different Residual and Weight Coefficient in Model Updating of Bridge Structure

Relative merits of different residuals used in the construction of objective function and weight coefficients in single-objective function for structural model updating are investigated in this paper based on the improved genetic algorithm (IGA). Presently there are three residuals which are used mostly in finite element (FE) model updating: frequency residual, mode shape residual, and modal flexibility residual. Relative merits of the three residuals are analyzed through the simulation of a simply supported beam. Then, model updating is studied comparatively based on IGA. Frequency is the main characteristic parameter of bridge structure, which has high identification precision and should be used with priority. When there are several updating parameters, information should be complemented. If identification error of the mode shape is relatively less, the complement of the mode shape is feasible. In the end, through the analysis of weight coefficients for different residuals in single-objective function, it can be seen that the model updating performance is better when the frequency residual has a larger weight coefficient.