A linear mathematical model for the seismic inplane behaviour of brick masonry walls part 2: Determination of model parameters through optimization using experimental data

The parameters appearing in the mixture and effective modulus models proposed in Part 1 are determined through optimization by matching theoretical and experimental responses. The optimization analysis is performed in frequency space. The response quantities chosen to be matched are the complex frequency response functions (experimental and theoretical) relating the Fourier transforms of top and base accelerations of the wall. Computations in optimization analysis are carried out by introducing an object (error) function and minimizing it using the Gauss-Newton method. The results show that the mixture model is capable of predicting accurately the dynamic response of masonry walls up to a frequency which is well above the second modal frequency, whereas the effective modulus model describes the wall behaviour only up to the first modal frequency. Furthermore, it is shown that the mixture model is still valid when micro cracks, which may exist between the mortar and brick constituents, are present. Copyright © 1984 John Wiley & Sons, Lt