Identification of ground motion time history and structural parameters based on absolute acceleration observations
In this study,based on the extended Kalman filter (EKF),an approach is proposed for identifying unknown ground motion time history and structural parameters by using the absolute acceleration measurements.First,the interfacial force of the lower boundary of the 1st floor is considered as the unknown excitation.The EKF-based approach is employed for the identification of this unknown excitation and the remaining structural stiffness parameters.Then,by using Fourier transform,the structural natural frequencies can be obtained from the acceleration measurements and used for identifying structural stiffness of the 1st floor.Finally,based on these identified structural parameters,the unknown interfacial force mentioned above is updated and employed for identifying ground acceleration with the aid of Newmark-β method.The effectiveness of the proposed approach is validated via a numerical frame structure and a five-story experimental model under shaking table tests.