EVALUATION OF FRAGILITY CURVE ON TRAFFIC FUNCTION OF RIVER DIKE BASED ON STRONG MOTION ESTIMATION CONSIDERING EMPIRICAL SITE AMPLIFICATION AND PHASE EFFECTS —THE CASE OF THE NARUSE RIVER DIKE FOR THE PAST LARGE SCALE EARTHQUAKES—

Abstract

 Serious damages were occurred by the 1978 off Miyagi Prefecture Earthquake, the 2003 northern Miyagi Prefecture Earthquake and the 2011 off the Pacific coast of Tohoku Earthquake, especially for the the Naruse River dike. In this study, seismic waveform evaluation was conducted at numerous sites along the dike based on empirical site amplification and phase effects. Using both the actual damage data and detailed distribution of the estimated ground motion, this study conducts the statistical analysis on the relationship between the damage ratio and several indices of the ground motion to construct fragility curves. Based on the obtained results, serious damages that affect the serviceability for traffic are found in the area where the SI value by Housner is larger than about 15 cm/s.