Nagano Expressway For falling concrete pieces from the Chikuma River Bridge
about

NEXCO EAST Kanto Regional Head Office (Taito-ku, Tokyo) manages Nagano Expressway 's Chikumagawa Bridge, a concrete piece on a riverbed that intersects with Expressway. There was an event of falling. No damage such as injuries or property damage has been confirmed.

There is no problem in driving safety as it is not a damage that hinders the structure of the bridge.

We are currently conducting emergency inspections to prevent similar events from occurring on the bridge. We apologize for any inconvenience caused to our neighbors.

1 History of discovery

The 1st report to our company At about 16:00 on February 22, 2013 (Friday), the general public informed us that the concrete piece had dropped, and confirmed the concrete piece on site.

2 Occurrence location

Intersection of Nagano Expressway Chikumagawa Bridge (74.4KP) and first-grade river Chikumagawa (left bank)
(Between Aso Interchange and Sarah Interchange opened on March 25, 1993)
Site name: Shinonoi Shiozaki, Nagano City, Nagano Prefecture

3 dropped concrete pieces

The maximum size of a concrete piece that falls within a height of approximately 20 cm, a thickness of approximately 13 cm, and a length of approximately 7 m is approximately 20 cm in height, approximately 13 cm in thickness, approximately 53 cm (approximately 13 kg) in length.

4 Cause of fall

It is highly probable that rainwater invaded due to aging of the concrete and the reinforcing bars corroded and expanded, causing the concrete to peel off and fall.

5 Inspection history of the location

The inspection was conducted in July 2012, and minor damage was confirmed.

6 Response status at the relevant location

We are currently conducting an emergency inspection of the bridge, which is scheduled to be completed tomorrow by the end of February 24th.

[Drop situation diagram]

[Situation photo]