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JICOSH Home > Case Studies > Case No.66
Case No.66

Hit by a falling hammer during the assembling of a pile driver

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[Description of the Accident]

This accident occurred when a worker's head was caught between a falling hammer and the pile cap while a pile driver was being assembled for foundation construction work at a residential building construction site.

At the time of accident, the pile driver was being reconfigured to carry out both pile driving and earth augering functions. The reconfiguring work involved first removing the working part of a drag shovel, then assembling the earth auger, connecting the upper and lower portions of the pile driver leader with bolts, mounting the hammer on the hook, and placing a pile cap under the leader. At the final stage of the work, the cap and the hammer were to be connected by a wire cable.

On the day of the accident, two workers started the assembly work. When the pile driver operator shortened the machine arm to lower the suspended leader to the position of the cap, the hammer also came down and the head of the other worker was caught between the hammer and the cap while he was assisting the assembly work. The victim was rushed to a hospital by ambulance, but died due to a fractured skull.

[Causes supposed]

1. The victim put his head between the hammer and the cap while the pile driver operator was lowering the leader.

2. After completing the work to position the metal cap guide, the pile driver operator started to lower the leader without confirming a voice response from the victim.

3. Working procedures for mounting the cap had not been clearly established.

4. The pile driver operator had not completed a skill-training course for vehicle-type construction machinery (for foundation work).

[Type of business] Wooden house construction
[Caused by] Construction machinery for pile driving
[Type of accident] Caught in or compressed by equipment
[Number of victims] One fatality