Seismic reliability of high-speed railway considering composite damage types using 2004 M6.6 Niigata earthquake case history

초록

Seismic reliability of the high-speed railway is estimated from the damage potential analysis of railways resting on the flat ground, tunnel, and the viaduct or bridge. Investigating the damage potential for each railway infrastructure requires either large amount of case histories or in-depth numerical analyses, or both, which requires large amount of time to accomplish thoroughly. In this study, rather than performing detailed study for each damage case, we collect and analyze a case history of high-speed railway system damaged by the 2004 M6.6 Niigata Chuetsu earthquake for the estimation of seismic reliability. Severe to minor damages occurred by the event along the high-speed railway from Echigo Yuzawa station to Niigata station where the length is approximately 118 km. Damage patterns observed include: electric poles tipped over; railways bent; tunnels damaged; bridge or viaduct columns damaged. We classify these damage patterns into five types and four severity levels and assign each damage type and level at segments for which the unit length is 200 m. Then, by aggregating the damage levels with similar intensity measures predicted on each segment, the scenario-based seismic fragility function is developed. We found that among intensity measures considered, the PGV has the most prediction power for the probability of damage occurrence. This approach provides preliminary expectation of seismic damage on high-speed railway given an intensity measure, which can be used for emergency response plan for possible earthquakes in the future.