Seismic Response Arising from Traveling Waves

Abstract

Over the years, observations of earthquake damage suggest that structures on large foundations respond to ground motion with less intensity than do smaller structures. The limited data obtained from instruments support these observations. The theoretical investigation described constitutes an attempt to establish the feasibility of employing the τ‐averaging traveling seismic wave procedures to investigate the effects of combined lateral motion resulting from translation and rotation of a simple structure. The results of the investigation indicated that the effects of induced rotational motion (computed by this technique) are not important at frequencies less than 1 Hz. Various approaches for combining the responses are studied, involving direct superposition approaches and coupled motion approaches. The results of this limited study suggest that the 5% accidental eccentricity, as specified in building codes, appears reasonable.