| Case Name |
Concrete mould timber support collapse accident in the gymnasium construction work. |
| Pictograph |
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| Date |
February 14, 1992 |
| Place |
The Kanagawa Prefect. Ayase City. |
| Location |
The gymnasium construction site in Maritime Self-Defense Force Atsugi air base. |
| Overview |
During concrete installation of the slab and the girder of the second floor of the gymnasium, the built trusses which supported the mould for the slab fell down. About 25 minutes later, a chain reaction collapse of the moulds and the mould timber supports spread from this falling point, and 2/3 of concrete and slabs reinforcing of the second floor fell down. |
| Incident |
Timber supports of the moulds successively collapsed and fell down during concrete installation of the slab and the girder of the second floor and the wokers who were working on inspection, etc. at the 2 and 1 floor were pinned under these fallen materials, and 7 died, and 14 got injured. |
| Sequence |
By the previous day of the accident, concrete was placed in such as first floor column and the external wall to the under the girder mould. And during concrete installation of the slab on the day of the accident, a beamed member of the built truss fell on the shelf scaffold just below that with coffer forms ( the mould boards ) of its both sides and placed concrete in it. The installation work was immediately stopped, and some persons descended to the first floor to grasp the situation. after about 25 minutes A collapse of the mould timber supports began from the part of this built truss, and it spread rapidly, and it lead to the whole collapse. |
| Cause |
That they started the construction with insufficient manpower and adopted unaccustomed construction method in order to simplify the construction. And that as the result, the fixations of the members and the mounting arrangement of the scaffold, etc. was imperfect and, and that the falling of some of members caused the buckling of the mould timber support column. |
| Response |
Remedial work started after 2 months. |
| Countermeasures |
When new or unaccustomed method are introduced, collect data such as results of introduction in other construction and the experience of the woker, and examine the safety adequately. |
| Knowledge Comment |
Do the basic works accurately such as mounting of the scaffold, etc.. |
| Background |
The labor shortage of the construction industry which continued from bubble economy period.
Enforced acception of order by single tendering at the cheap amount of money.
The innovative construction method in which there are hardly experienced. |
| Reason for Adding to DB |
Since it is a large accident which killed as many as 21 people and socially noticed. |
| Scenario |
| Primary Scenario
|
Insufficient Analysis or Research, Insufficient Prior Research, Insufficient Analysis or Research, Insufficient Prior Research, Poor Concept, Poor Strategy or Concept, Production, Hardware Production, Non-Regular Action, Inaction, Failure, Large-Scale Damage, Bodily Harm, Injury, Bodily Harm, Death, Damage to Society, Social Systems Failure
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| Sources |
The concrete mould timber support decay disaster in the gymnasium construction work in Maritime Self-Defense Force Magnolia bark air base investigation result report ( 1993 Ministry of Labor ).
|
| Number of Deaths |
7 |
| Number of Injuries |
14 |
| Physical Damage |
Mould timber support, concrete, etc.. |
| Field |
Civil Engineering
|
| Author |
SATO, Takefumi (The University of Tokyo)
KUNISHIMA, Masahiko (The University of Tokyo)
|
