HYSTERESIS AND PARAMETER ESTIMATION OF MDOF SYSTEMS BY A CONTINUOUS-TIME LEAST SQUARES METHOD

Civil structures could undergo hysteresis cycles due to cracking or yielding, when subjected to severe earthquake motions. Seismic instrumentation, structural monitoring and system identification techniques have been used in the past years to assess civil structures under lateral loads. The present research makes use of a continuous-time Least Squares Method, modified herein to consider the nonlinear behaviour of the structure. The proposed on-line algorithm simultaneously estimates the hysteretic component and structural parameters such as damping and stiffness of a shear building structure. Simulations are carried out using the El Centro and the Mexico City seismic records. Fair convergence speed is obtained for the identification of the parameters and the estimation of the hysteretic component.