superannuated
笹子トンネル事故では劣化したボルトが原因ではないかという見解が有力になっています。劣化はagingでも言い訳ですが，本文ではsuperannuatedが使われていました。これには「老朽した」のほか「古びた」という意味合いも含まれます。（UG）
No repairs made since '77; death toll hits nine
Fatal tunnel collapse blamed on aging bolts
Kyodo
KOFU, Yamanashi Pref. — Sunday's expressway tunnel collapse in Yamanashi Prefecture that killed at least nine people may have been caused by aging ceiling bolts that failed, Central Nippon Expressway Co. said Monday.
Facing reporters Monday in Nagoya, where the highway operator is headquartered, Ryoichi Yoshikawa, CNEC executive in charge of maintenance, said failed bolts were found at the site where tons of concrete ceiling panels fell onto vehicles traveling through the Sasago Tunnel.
"Superannuated (bolts) may be" the cause of the tunnel collapse, Yoshikawa said, suggesting the bolts were never replaced. "There is no record that shows repair work was carried out in the past."
