Emergency inspection of tunnel ceiling panels in NEXCO EAST

December 3, 2012
East Nippon Expressway Co., Ltd.

We would like to pray for the souls of those who died in the accident of the collapse of the tunnel ceiling panel in NEXCO CENTRAL, and we would like to express our sincerest sympathies to the bereaved families.

NEXCO EAST, About emergency inspection of tunnel ceiling board Based on the instructions of ", we perform the following emergency inspections.

1. Tunnel to be inspected

Expressway, which is managed and operated by NEXCO EAST, does not have a tunnel with a ceiling plate installed over the entire extension. In the tunnel to be inspected this time, a ceiling plate is partially installed at the place where ventilation equipment such as a dust collector is installed.

No. Admin Route name Tunnel name Up and down
Another
tunnel
Extension (km)
Of which ceiling plate
Installation extension (km)
Remarks
1 NEXCO
East Japan
Kan-Etsu Expressway Kanetsu tunnel In-bound line 11.1 0.17  
2 Out-bound line 10.9 0.15  
3 Hokuriku Expressway Nou tunnel Out-bound line 3.0 0.02  
4 Takamine tunnel Out-bound line 3.1 0.02  
5 Child ignorance tunnel In-bound line 4.6 0.05  
6 City swing tunnel Out-bound line 3.3 0.05  
7 Aqua Line Tokyo Bay Aqua Tunnel In-bound line 9.6 0.30  
8 Out-bound line 9.6 0.30  
9 Nagano Road Tachitoge tunnel Out-bound line 3.6 0.02  
10 Joshin-Etsu Expressway Gorigamine tunnel In-bound line 4.5 0.04  
11 Happu-san tunnel Out-bound line 4.5 0.05  
12 Taro mountain tunnel In-bound line 4.3 0.02  
13 Ken-O Road Sugawa Tunnel In-bound line 2.4 0.04  
14 Out-bound line 2.4 0.04  
(11 tunnels: 14 tubes, target length 1.3km)

2. Inspection method and contents

Ministry of Land, Infrastructure, Transport and Tourism About emergency inspection of tunnel ceiling board Based on the above, the following contents were inspected by close-up visual inspection, tapping, and palpation.

  • (1) Ceiling board suspension fittings and fixing fittings
  • (2) Soundness of the lining concrete near the fixed parts of the ceiling plate suspension fittings and the pedestal
  • (3) Presence/absence of deformation or damage to the ceiling plate
  • (4) Presence of other events that may lead to the fall of the ceiling plate, etc.
  • Before inspection, make sure to pay attention to the condition of the ceiling board and traffic conditions in advance to prevent accidents.

3. Inspection completion time

Scheduled to be completed on Wednesday, December 12, 2012

[Reference] Current inspection status (Kan-Etsu Expressway Kanetsu Tunnel, In-bound line, near the ventilation area)

Ceiling board installation status

Tapping and palpation inspection status