Abstract
Tsujun Bridge at Yamato town in Kumamoto was built in 1854 to send water for agriculture, and it suffered damage during 2016 Kumamoto earthquake. Field measurement was conducted on the Tsujun Bridge to determine natural frequencies and damping constant of the structure. Ambient vibration induced by people jumping was observed using a velocimeter. Simplified cone penetrometer tests also were conducted in the vicinity of the bridge to determine the strength of soil around the bridge. Further, earthquake response during 2016 Kumamoto earthquake was estimated using the identified natural frequency and damping constant. The results showed that the maximum acceleration response during the earthquake was estimated as 1.2G.
