Structural damage detection of a shear building under unknown earthquake excitation with limited observations of absolute acceleration reponses

Here, a method was proposed for structural damage detection of a multi-story shear building under unknown earthquake excitation with partial observations of absolute acceleration responses. Based on the extended Kalman estimator and the least square estimation adopted sequentially, the structural parameters above the first story of the building could be identified. Then, the structural parameters of the first story were identified with the frequency equation. Finally, the unknown earthquake excitation identified via the numerical solution to a first-order differential equation. It was shown with a numerical example that the proposed method can identify structural parameters and earthquake excitation with good accuracy; structural damage under unknown earthquake excitation can be detected by tacking degradation of structural stiffness parameters.