Seismic response analysis on the stability of running vehicles

SUMMARY The seismometer network of the Japanese expressway system has been enhanced since the 1995 Kobe earthquake. Using earthquake information from the instruments, the expressways are closed if the peak ground acceleration (PGA) is larger than or equal to 80 cm=s 2 . The aim of this regulation is to avoid secondary disasters, e.g. cars running into the collapsed sections. However, recent studies on earthquake damage have revealed that expressway structures are not seriously damaged under such-level of earthquake motion. Hence, we may think of relaxing the regulation of expressway closure. But before