Verification to the breakage of center stay rod of the first Kurushimakaikyo bridge and field observation in the Geiyo earthquake

摘要

Due to the Geiyo Earthquake in March 24th, 2001, center stay rods of the 1st Kurushimakaikyo Bridge (suspension bridge) were broken. They were designed to break in strong earthquake and work as safety valve of the structure. In order to evaluate the mechanism of the breakage of the roads, data from field measurement were processed using structural analysis, and it was confirmed that the broken rods worked as designed. It also was confirmed that forces acted to other unbroken rods in 2nd and 3rd Kurushimakaikyo Bridges were not large enough to affect their soundness. Through this experience, it was proven that field measurements and structural analysis can be effective tools not only for design but also for maintenance of structures.