Abstract
The design spectra of Seismic Deformation Method for under ground structures have been given by the velocity response spectra defined on the seismic base layer. In this paper, a new method is proposed to define the design spectra in terms of the acceleration response spectra on ground surface. The proposed method makes possible to include the seismic and ground environment in the design spectra of under ground structures. In order to compare the proposed method with the conventional method, a conversion procedure of the spectrum defined on the ground surface into that of Seismic Deformation Method is proposed. The procedure is applied to the seismic design spectrum of Earthquake Resistant Design of Bridges of Japan and the average response spectra determined from 394 components of the strong motion records. The converted spectra are compared with the design spectra defined in various codes for underground structures.
