A condition assessment method for the time-variant seismically isolated structure

摘要

In this paper, a new time-variant structural system identification method is proposed based on a simultaneous identification strategy. The method can be used for the seismic condition assessment of base isolated nonlinear structures. Excitation decomposition and an improved Unscented Kalman Filter (UKF) are utilized for the implementation of the nonlinear structural system identification. The structural excitation is decomposed by orthogonal approximation. With this approximation, the strongly time-variant excitation identification is transformed into gently time-variant and even constant parameters identification. The proposed method is validated numerically with simulation studies on a base isolated nonlinear structure subjected to earthquake excitation and impact load from the retain wall. It is shown that the proposed method can identify the excitation and parameter of the nonlinear structure with measurement noise. A real-time hybrid test is also conducted to validate the proposed method. Results from this experimental study indicate that the proposed method is able to identify the dynamic load and structural parameters fairly accurately with measurement noise and model error.