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JICOSH Home > Case Studies > Case No.85
Case No.85

Truck crane topples while trying to unload a drag shovel from the truck crane


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[Description of the Accident]

A truck crane toppled during work to unload a small-sized drag shovel that was transported on this vehicle-carrying truck crane at the construction site of a new house.

On the day of the accident, a worker of the lease company that had been requested to transport the drag shovel loaded the small-sized drag shovel on the vehicle-carrying truck crane and arrived at the construction site. Following the instructions of a responsible person, he moved the truck to an elevated site (being prepared by another company) located higher than the site for the foundation work and was preparing to unload the drag shovel to the ground some 1.8 m lower.

Prior to unloading the drag shovel, the worker extended the outrigger of the truck crane to the maximum and laid blocks under a jack. The worker then slung a wire rope inserted into the drag shovel boom. When the worker moved the drag shovel to the unloading position, the blocks under the outrigger jack broke and the truck crane toppled over at the same time. The worker who was driving the truck crane was caught between part of the falling truck crane and the retaining wall.



[Causes supposed]

1. The blocks laid under the jack base fittings of the truck crane outrigger broke.

2. Although it was necessary to lay steel sheets, etc., because of the soft ground, work was carried out without taking such measures.

3. A worker without legal qualifications was permitted to operate a mobile crane.
[Type of business] Goods leasing
[Caused by] Mobile crane
[Type of accident] Caught or trapped
[Number of victims] One fatality
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