| Case Name |
Tachikawa City, the falling accident of the pile driver |
| Pictograph |
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| Date |
March 16, 1991 |
| Place |
Tokyo, Tachikawa City, Akebono town |
| Location |
A construction site of a new building |
| Overview |
In Akebono town , Tachikawa City, Tokyo, at the construction site of Tachikawa JF building which was operated by a joint venture of major general contractors, the large pile drive for the sheeting(weight: about 100ton, height: about 30m) fell down to the east side with a roaring noise. Total of seven buildings including private houses and apartments were buried under the machine. Two citizens were killed in the accident. |
| Incident |
On 16th, March, 1991, the accident occurred at just after 9:30a.m. In Akebono town,Tachikawa city,Tokyo,at construction site of Tachikawa JF building which was operated by a joint venture of major general contractors, the large pile driver (weight: about 100ton, height: about 30m) fell down to the east side with a big noise.Some private houses and apartments were buried under the machine.Apartments were collapsed completely, two buildings were destroyed partially, and the parts of three buildings were broken.In this accident, two people were killed.They were university students.The workers in this site were not injured. |
| Sequence |
On the day,they were digging, the holes with the pile driver in order to drive the piles for foundation work and reinforcement for the ground around the site.There were over 10 sheets of steel(width: about 1.5m, length: about 6m, thickness: about 2cm) on the site.The pile driver had moved on the sheets, but the ground was too muddy. Around this area, rocks in underground were removed and soil was backfilled before the foundation work.
After the same operation of the pile driver on the east side of steel sheets, it moved back and the driver descended.Just after that, the head of the machine shank with the steel sheets started to lean.The driver noticed this and tried to drive and move the machine falling down with hooping one of the eastside steel sheets up ,making a big noise. |
| Cause |
1.They didn't take the safety countermeasures which foresaw the loose ground .
2.They didn't fix it with the arm because the work would not been done yet.
3.The safety equipment was not put into motion because the switch of the safety equipment was switched off. |
| Response |
The site was near the JR Tachikawa station. The JR TACHIKAWA station was the center oh the town and has heavy traffic.Tens of fire trucks and ambulances rushed there, and the rescue operation by the helicopter was carried out. The rescue team searched for the bottom of the collapsed house using the fiberscope. They tried to extend the clearance by hydraulic jacks, etc. for the rescue, but the rescue operation was difficult because of the fallen arms. |
| Countermeasures |
As a safety countermeasure in the case of the construction using heavy machine in the place with the soft ground, the tipping over prevention, and the ground made to be reliable by injection of coagulating agent, etc.; are necesary before the construction is carried out. After materials such as the outrigger are projected in the circumference of heavy machine, it is a considerable countermeasure to prevent falling.. |
| Knowledge Comment |
1.The elaborate geological survey beforehand must be carried out, as it can prevent tipping over of construction heavy machine .
2.In the case of using the heavy machine over the weak ground which has the possibility of tipping over, the coagulating agent is not be injected, etc. to make the ground firm.
3.Even while the construction heavy machine is not driven, it must be kept in the stable condition by supporting it with the arms etc.
4.The condition of the safety equipment can always be operated . |
| Background |
At that time, tower building construction was increasing in Tokyo because of the economic growth. Especially in Tokyo, the constructions of high buildings was increaseing in residental towns. According to it, the case in which the industrial accident involved nearby inhabitants and passers-by increased. There are many cases which cause a collapse, because the leveling of ground work is not sufficient, in order to introduce the large machine into the place without the even space. Again, according to the enlargement of the construction work, over-heavy objects were held by the high machine for construction, for example, pile drivers and crane trucks. It make the machine to lose balance easily . Especially it is said that it is especially dangerous to work on the soft ground. |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Insufficient Analysis or Research, Insufficient Prior Research, Usage, Operation/Use, Regular Operation, Nonobservance of Procedure, Failure, Fracture/Damage, Failure, Fracture/Damage, Bodily Harm, Death
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| Sources |
"The construction accident" ( Nikkei construction edition, 2000 ).
Nihon keizai shimbun, Asahi shimbun, Mainichi Shinbun, Yomiuri shimbun
|
| Number of Deaths |
2 |
| Number of Injuries |
0 |
| Multimedia Files |
Fig2.The falling crane
|
| Field |
Civil Engineering
|
| Author |
KUNISHIMA, Masahiko (The University of Tokyo)
TOYOTA, Kouichiro (The University of Tokyo)
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