DAMAGE ASSESSMENT OF SEWER BURIED PIPES SUBJECTED TO GROUND MOTIONS AND LIQUEFACTION IN PREVIOUS EARTHQUAKES

Abstract

 In this study, we analyzed the damage of sewer buried pipes by strong ground motions and liquefaction in the past earthquakes: the 1995 Kobe earthquake, the 2004 Niigata Chuetsu earthquake, the 2007 Noto Hantou earthquake, the 2007 Niigata Chuetsu-oki earthquake, the 2008 Iwate-Miyagi Nairiku earthquake, and the 2016 Kumamoto earthquake. After we defined the damage ratio R by dividing the damage length L_d of the buried pipe length L, we revealed the characteristics of the damage ratio to the peak ground acceleration PGA, the peak ground velocity PGV, the instrumental seismic intensity IJ and the SI value as an index of the ground motion intensities from view of points of pipe types, diameter and classification of microtopography. We further analyzed the dependency of the damage ratio on the ground motion intensities and revealed the trend of damage ratio data classified by VP/VU pipe type, diameter of Φ<300 mm, and non-liquefaction.