| Case Name |
Collapse accident of support of aqueduct facilities |
| Pictograph |
|
| Date |
January 2000 |
| Place |
Oita Prefecture |
| Location |
The interchange improvement work field |
| Overview |
During widening construction of the aqueduct facilities, the center of the mold supports of the top of the aqueduct facilities collapsed during installation of freshly-mixed concrete, and freshly-mixed concrete and moulds steel products fell on the roadway. |
| Incident |
During installation of concrete on the road, the central mould timber (H=6,500mm) which supported the top of the aqueduct facilities was crushed by the load made up of freshly-mixed concrete and it collapsed, and the freshly-mixed concrete and the moulds steel product fell on the roadway.Therefore, the roadway was stopped for 12 hours. |
| Sequence |
* At the beginning of the plan, the prop width of the central support was 900mm.
* The prop width of the central timber support was changed to 700mm because of the constraint of the width of the street.
* The subcontracting company miscounted the member of supports picked up . (The members of horizontal bracing and perpendicular brace were insufficient)
* They miscounted the member of support carried in.
* The subcontracting company constructed supports of which horizontal bracing and perpendicular brace were insufficient without confirming the drawing.
* During the installation of freshly-mixed concrete, the load exceeded the strength which the support prop and perpendicular brace of the central possessed, and the central support buckled and collapsed. |
| Cause |
* The subcontracting miscount the member of supports picked up .
* The subcontracting company carried the incorrect members in the field and constructed without the confirmation of the drawing.
* The operation chief of the subcontracting company did not check the drawing after the completion of the assembly.
* The principal contractor did not inspect before, during, and after the assembly of the support. |
| Response |
* The promoter founded the investigation committee of the accident.
* The field study was carried out with the expart on disaster prevention (man of learning and experience).
* Afterwards, the investigation conference of the cause was held 7 times and the result were announced at a press conference about the collapse accident.
The promoter notified the following matters and attempted the strengthening of the safety countermeasure.
* The safety inspection on construction field
* The safe confirmation of the construction of the space, with ensuring passage through the current road
* The construction with the danger of the public disaster
* The safety countermeasure of the construction and strengthening of the supervision and the inspection system
* The strengthening activity of the safety countermeasure of construction work
* The eradication activity of the construction accident
* The supervision of the construction with the temporary |
| Knowledge Comment |
* Construction and drawing are surely checked.
* The principal contractor and the subcontractor should inspect carefully. |
| Background |
* The employee of the contracting company worked carefully on the drawing and the preparation of negotiation material with the organizations.
* The contractor did not report to the Labor Standards Inspection Office that they changed the width of the support from 900mm to 700mm. |
| Sequel |
The past contracting company were stopped to be nominated in 2 months. |
| Account of Concerned Parties |
Though the extra members were remained after assembly, the subcontractor did not mind that. |
| Reason for Adding to DB |
This accident was caused by the fact that the checking function for temporary structure by the contracting and the subcontracting company did not work. It is very important to check even if it is simple work and accustomed work. |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Ignorance of Procedure, Disregard of Procedure, Organizational Problems, Poor Management, Planning and Design, Poor Planning, Incorrect Reaction, Poor Communication, Failure, Deformation, Damage to Society, Social Systems Failure, Loss to Organization, Social Loss
|
|
| Number of Deaths |
0 |
| Number of Injuries |
0 |
| Field |
Civil Engineering
|
| Author |
MIZOGUCHI, Hiroki (National Institute for Land and Infrastructure Management)
|
