| Case Name |
The load break accident of the pile of steel sheets that put temporarily. |
| Pictograph |
|
| Date |
July 2001 |
| Place |
Yamagata Prefecture |
| Location |
The construction site of slope repair work. |
| Overview |
In the slope repair construction site, a bundle of the pile of steel sheets put in the unstable condition, dollapsed. And there was a worker who was working between bundles of the pile of steel sheets put on the side. He died. |
| Incident |
At the slope repair construction site, while piles of steel sheets for a temporary protective fence were being moved, some steel sheets (2 bundles of 10 sheets; the SP III type) collapsed. They had been put into trapped 2 bundles (height: 1.45m). A worker, who was working at the side of them, died. He was trapped between 20 collapsed steel sheets (upper bundle L=6.5m, Weight=3.9t, lower bundle L=9.0m, Weight=5.4t) and the bundle of 10 steel sheets which had been put next to them. |
| Sequence |
* When the work started, 2 slinging workers carried out the work according to the operational procedure decided in the meeting. But, the victim had worked alone right before the accident.
* There was no agent, boss or responsible person of the subcontract present when the accident happened.
* He moved the steel sheets put temporarily around the doorway to allow cars for the construction to come in the site from the road. There were 5 bundles of 10 sheets.
* They intended to lift a bundle of 2-3 steel sheets depending on the ability of the crane, and move them to the back. But they lifted a bundle of 10 steel sheets at once in order to finish the work early.
* When a bundle of 10 sheets was lifted up, he couldn't move it to the right position and piled it on the next bundle of 10 sheets.
* When the worker (the victim) was doing the slinging work to move the next bundle of steel sheets, these piled bundles of steel sheets collapsed. And, the worker was crushed between bundles of steel sheets, which the worker had intended to lift. |
| Cause |
* The wood, laid under the lower bundle of steel sheets, and could not resist the weight of piled bundles of steel sheets. So, they broke and collapsed.
* They piled bundles of steel sheets though it had been forbidden in the previous arrangement. They did the forbidden work to pile bundles of steel sheets which number was more over than the number of sheets the crane could lift, and the right position was not in the operation radius.
* In the previous arrangement, workers needed to move a bundle of 2-3 steel sheets. But, actually they moved a bundle of 10 sheets. |
| Response |
1.The work was stopped. Then the general contractor and decided on the subcontractor the victim belonged to examined the cause of the accident and countermeasures for safety in the future in the urgent safety meeting.
2.Before the construction restarted, the retraining was done about the method of the work in the site.
3.After the accident the owner had the contractor initiate the following modifications:
* They need to review and follow the manual of the operational procedure.
* They need to present the ledger about the construction system.
* There must be a full time safety manager on a construction site.
* It is important to make someone cover for the agent of the site when he leaves the site.
4.The contractor reported countermeasures to prevent accidents in future to the owner and attempted to have everyone in the company understand them completely.
* In the previous arrangement before the work, workers have to confirm their work and the operational procedure, and have to work according to the defined procedure.
* The worker who has to lift something with danger must be a well-experienced worker.
* It's important to confirm the capacity of the crane and carry out the work within the suspension road and the operation radius which are suitable for the ability of the crane.
* They must not do unstable `piling bundles of steel sheets'.
* If they place steel sheets temporarily, they have to adopt measures to prevent falls, for example, linking to the H steel, etc.
* There must be at least 1 person such as an agent or a boss or a person in charge on a site. The work director (who manages the construction site) must be permanently stationed at the site. |
| Knowledge Comment |
* Piled materials require the consideration about their stability.
* The work director has to be permanently stationed and should confirm whether the work is safe at the site.
* They have to adopt measures to prevent falls when they work near materials which have the risk of falling. |
| Background |
1.The situation of the site
* The cross gradient of the road was about 3 % and there was the risk that piled steel sheets would collapse on the victim.
* The slinging worker was at the blind spot from the operator of the crane. And it was impossible to change the arrangement of the crane because of a physical reason. The site was too small to change.
2.The situation of safety management in the construction site
* There was no staff of the contractor and operation chief in the site when the accident occurred.
* In the notebook in which things decided in the meeting the day before were written, there was no description of the safety indication. It became clear that the information had been insufficient in the site, by the record of the safe patrol.
3.Contractor and workers
* The contractor, that actually carried out the work, had set the fence to protect workers from falling rocks by using steel sheets (SP III type) for the first time, then.
* Two years had passed since the victim entered the company. And 1 year since he finished classes for the slinging skill.
4.The background of the operational procedure:
* They had an arrangement for change before they carried out the unscheduled work. And they would move a bundle of a few steel sheets.
* It was forbidden to pile bundles of steel sheets as in the previous arrangement. |
| Sequel |
* The victim swung piled bundles of steel sheets and intended to confirm whether they were unstable. But they had collapsed.
* They didn't move a bundle of a only few sheets because they thought that they could completely finish the work by a bundle of more sheets. When they lifted a bundle of 10 sheets, the warning buzzer of the crane rang Then they piled a bundle of steel sheets on another. |
| Incidental Discussion |
In the narrow working area, when someone around there discovers unsafe actions and facilities, they had better correct the system of the site immediately. |
| Account of Concerned Parties |
The stability of piled bundles of steel sheets
* The crane operator wasn't especially anxious that steel sheets were placed temporarily.
* When bundles of steel sheets were piled up, the crane operator couldn't confirm the instability of the steel sheets. |
| Reason for Adding to DB |
* This case is a basic accident case caused by elementary errors such as the work done on one's own and neglecting operational procedures.
* It is significant to confirm the stability of materials which have risk of falling. |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Ignorance of Procedure, Disregard of Procedure, Organizational Problems, Poor Management, Regular Movement, Wrong Movement, Regular Movement, Dangerous Movement, Failure, Deformation, Bodily Harm, Death, Loss to Organization, Social Loss
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| Number of Deaths |
1 |
| Number of Injuries |
0 |
| Physical Damage |
None |
| Field |
Civil Engineering
|
| Author |
MIZOGUCHI, Hiroki (National Institute for Land and Infrastructure Management)
|
