This paper investigates the response of structural systems to strong earthquake ground shaking by utilizing some concepts of system identification. After setting up a suitable system model, the Weiner technique of nonparametric identification has been introduced and its experimental applicability studied. The sources of error have been looked into and several new results have been presented on accuracy calculations stemming from the various assumptions in the Wiener technique.
The method has been applied in studying the response of a 9-story reinforced concrete structure to earthquake excitation as well as ambient vibration testing. The linear contribution to the total roof response during strong ground shaking has been identified, and it is shown that a marked nonlinear behavior is exhibited by the structure during the strong-motion portion of the excitation.