Abstract
In this paper, the authors propose the method of calculation to obtain the In-put waves deducible from the response waves measured on a building at the time of earthquake, by eliminating the effect of self-vibration of building. This calculation method and the In-put waves thus obtained may be called "the Inverse-response calculation" and "the Inverse-response waves", respectively. In this analysis, a building is treated as a multi-story system allowing the sway of foundation, and the Inverse-response waves are calculated by applying the modal analysis, Fourier transform and inverse Fourier transform. In this study, the vibration tests were made of a model building by means of the random-shaking table, to confirm practically the above calculating method adaptable, and further, the Inverse-response waves were calculated from the observed waves on several actual buildings in Tokyo at the time of Higashimatsuyama earthquake on July 1, 1968 (Intensity=IV, (JMA scale), in Tokyo). From the results so far obtained, it has been concluded that the calculation method, which forms the subject of this paper is of a practical use to investigate the vibrational characteristics of the earthquake ground motions from the Inverse-response waves, especially in case of meagreness of the observation of the ground motion.
