ABSTRACT
Under an eathquake, structures might vibrate not only horizontally but also vertically due to a vertical excitation. Now the effect of the vertical excitation, however is not considered directly or with scientific justification. The effect of vertical excitation mus be studiesd to improve the seismic capacity of structures under real eathquakes. In this paper, the characteristics of vertical excitations are discussed comparing with horizontal excitations using 12 ground acceleration records including 1995 Hyogoken-nambu earthquake records as the first step. As the results, these can be said that the maximum vertical ground acceleration is generally smaller than the horizontal, the vertical input energy due to earthquake is less than the horizontal, but the response acceleraton is larger than the horizontal and vertical maximum response acceleration should accur at the same time. (AU)
