Three-step method for stiffness identification of inter-story shearing structures under ambient excitation

This paper presents a three-step method for the stiffness identification of inter-story shearing structures under ambient excitation. The transition from structural random response to deterministic response is realized by the natural excitation technique (NExT). The parameter-decoupled free vibration equation of inter-story shearing structures is deduced, which can simplify the procedure of identification and reduce the amount of calculation. Through the effective combination of the NExT, the parameter-decoupled method, and the extended Kalman filter (EKF) algorithm, a good scheme is presented for stiffness identification of inter-story shearing structures under ambient excitation. Using inter-story shearing structures with six-degree-of-freedom and ten-degree-of-freedom as examples, the scheme is tested by numerical simulation and experiment. The result shows that the maximum of identification error is 7.82%, and it can reach the requirement of engineering application basically.