PROPOSAL OF EVALUATION METHOD FOR AMPLIFICATION OF RESPONSE SPECTRUM BY SURFACE STRATA

A simple evaluation method for amplification of response spectrum by surface strata is proposed. The proposed method does not require any time history of design ground motion. That means the proposed method can be utilized in response and limit capacity calculation. In the proposed method, the response spectrum of design ground motion is converted to equivalent power spectrum density. The transfer function of surface strata is evaluated by one dimensional elastic wave propagation theory. The power spectrum density at ground surface is converted to response spectrum using peak factor. The good accuracy is achieved in evaluation of response spectrum amplification.