Health Assessment of Infrastructures Using Limited Uncertain Dynamic Response Information following Earthquakes

A health assessment technique for infrastructures is presented following earthquakes using uncertainty-filled information. A system identification (SI)-based concept is used to identify the stiffness of structural elements following earthquakes. The excitation information is not required, and responses need not be measured at all dynamic degrees of freedom. To consider uncertainty in representing a structure and dynamic responses, a significantly modified unscented Kalman filter (UKF)-based approach is used. To implement UKF, a two-stage SI approach is proposed. It is verified using three-dimensional truss-frame systems. The procedure is robust and not sensitive to the variances of initial stiffness and measurement noise, the two most uncertainty-prone parameters.