Damage of Nakasone No. 1 Viaduct and Discussion on Damage Mechanism

By Yoshikazu Takahashi.

March 17, 2011. Kyoto University.

Nakasone No. 1 Viaduct of the Tohoku Shinkansen Line suffered serious damage at the top of piers, especially the piers at the nearest end and furthest end from Tokyo lost the gravity load resistance by the loss of core concrete. In the first report, the failure mode of the piers was judged to be shear failure, but by comparing with damage mode of piers reported after the 2003 South Sanriku Earthquake and by considering the fact that the JR East Co. did not retrofit these columns in the first program for shear-failing piers, the failure mode is thought to be in not only simple shear mode but also flexural shear mode. This report discusses the reason.