THE ASSESSMENT METHOD OF THE REDUCTION FACTOR r_d OF THE SEISMIC SHEAR STRESS IN CONSIDERATION OF THE EARTHQUAKE MOTION CHARACTERISTICS AND GROUND CHARACTERISTICS

Abstract

 This study, in assessing the seismic shear stress ratio L of the assessment method of liquefaction based on F_L, is investigated the method to consider the influence of the earthquake motion characteristic and the amplification characteristics due to the nonlinearity of the surface ground.
 In this paper, in order to expand the application scope of the assessment method of the seismic shear stress using the earthquake motion record on ground surface that authors proposed, we investigated a simplified assessment method based on surface earthquake record about the reduction rate of S-wave velocity of surface ground by strain dependence.
 Furthermore, performed a regression analysis from the relationship between the calculated reduction factor of seismic shear stress by the proposed method by using a lot of strong motion observation records, and Indicators of surface earthquake motion and the ground. And, assembled a regression formula for estimating the reduction factor r_d of seismic shear stress.