Introduction
The Tohoku Earthquake occurred off the Pacific coast of Japan at 14:46 on March 11, 2011. The tsunamis and aftershocks that followed devastated many buildings and structures in the Tohoku region. The earthquake, tsunamis, and aftershocks are collectively referred to as the Great East Japan Earthquake.
The demolition of a building damaged by an earthquake is characterized by a high risk of building collapse. Moreover, demolition and other restoration or construction work are simultaneously undertaken at a single site, thereby increasing the likelihood of work-related accidents.
In this study, we analyze the work accidents that occurred during the restoration work for the Great East Japan Earthquake. The results are expected to find practical use in the prevention of disaster-related work accidents.
Methodology
We analyze the work accidents that occurred during the restoration work for the Great East Japan Earthquake. We identify accident causes and formulate safety measures. The data used in this study cover accidents that occurred during four-day intervals or more, spanning the period March 11, 2011 to September 11, 2012.
We also develop illustrations for each accident type and corresponding recommendations.
Results
Outline of work accidents
To date, the work accidents that have occurred at four-day intervals or more during the restoration work after the Great East Japan Earthquake have involved 642 people (including 36 fatalities). These statistics cover the period March 11, 2011 to September 11, 2012. Accident occurrence per month after the earthquake is shown in Figure 1. The highest number of work accidents occurred within the first month after the earthquake, affecting 111 people (including 6 fatalities). The work accidents follow a decreasing trend with the lengthening of time after the earthquake. The number of work accidents after 17 to 18 months was 12 (no fatalities).
An outline of fatal accidents is shown in Figure 2.
 |
Figure 1. Relationship between occurrence of number of accidents and passage of months.
 |
Figure 2. Outline of fatal accidents.
Occurrence by type
Accident occurrence by type is shown in Figure 3. Figure 3(a) illustrates the accidents that led to absence from work and fatalities, and Figure 3(b) shows the fatal accidents. For absence and fatal accidents, the “fall,” “get between,” “come flying,” and “fall down” groups affected 271 people (42.2%), 72 people (11.2%), 69 people (10.7%), and 45 people (7.0%), respectively. These four types of mishaps account for 71.1% of all work accidents. Falls occurred primarily during roof work.
The “fall” group led to the highest number of fatalities (16 people or 47.1% of all fatalities).
(a) Accidents leading to absence and fatalities. (b) Fatal accidents.
Figure 3. Occurrence by type.
Occurrence by causal agent
Accident occurrence by causal agent is shown in Figure 4. Figure 4(a) presents the accidents that led to absence from work and fatalities, and Figure 4(b) shows the fatal accidents. For the causal agents under absence and fatal accidents, the “roof, beam, purlin, and girder” group affected 87 people (13.6%); the “ladder and so on” group affected 66 people (10.3%); the “scaffolds” group affected 48 people (7.5%); the “building, structure” group affected 45 people (7.5%); and the “truck” group affected 44 people (6.9%). These five accidents account for 45.6% of all accidents.
The “roof, beam, purlin, and girder” group caused the highest number of fatalities (9 people or 25.0% of all fatalities). The “other’s construction machinery” group led to 4 fatalities (11.1%), and the “building, structure” group led to 3 fatalities (8.3%). These accidents account for 44.4% of all fall-related fatalities. The “ladder and so on” group did not cause any fatalities.
 |
(a) Accidents leading to absence and fatalities. (b) Fatal accidents.
Figure 4. Occurrence by causal agent.
Discussion
Practical use of the results
For practical use of these results, we developed illustrations for each accident type and corresponding recommendations (e.g., Takahashi, Hori, and Toyosawa, 2013). Examples of these illustrations are shown in Figure 5-7 (Case1- 3).
Case 1: The worker fell when he was repairing the blue sheet on the roof
 |
Figure 5 (a). The worker fell when he was repairing the blue sheet on the roof.
Case 1: Causes
1. Only one worker was present onsite and no operations chief was on duty.
2. The worker was not using a safety belt as he worked on the roof.
3. The roof was wet and slippery, but the worker was not wearing nonslip shoes.
Case 1: Prevention measures
1. An operations chief should always be on duty.
2. When a worker performs repairs at a level greater than 2 meters from the ground, he should use a safety belt. When scaffolds are erected, measures should be implemented to prevent falls. Examples of such measures include the installation of a net or the use of a safety belt. These measures should precede work on scaffolds.
3. When workers work at high locations, they should use premium-quality flexion and nonslip shoes.
4. The extent of damage to a building should be thoroughly examined before work is commenced. A work plan should be developed on the basis of the examination results.
 |
Figure 5 (b) . Examples of accident prevention measures.
Case 2: Construction machinery fell down as a worker performed demolition work for a house
 |
Figure 6 (a). Construction machinery fell down as a worker performed demolition work for a house.
Case 2: Causes
1. Demolition work and other restoration efforts were done at the same time in one construction site. No inductor was used.
2. The construction machinery was unsteady because of rubble and other debris.
3. The operator of the construction machinery did not ensure his safety.
Case 2: Prevention measures
1. Entry into areas with unsteady terrain should be restricted.
2. In cases where entry is unavoidable, an operations chief should be present onsite.
3. When demolition work and other restoration efforts are simultaneously underway in one construction site, workers should review operational procedures, promote collaboration, and ensure that construction machinery is in good working condition.
 |
Figure 6 (b). Examples of accident prevention measures.
Case 3: Structural steel components fell on a worker who was removing mud
Figure 7 (a). Structural steel components fell on a worker who was removing mud.
Case 3: Causes
1. The piled structural steel components were unsteady because of ground consistency.
2. In piling the components, workers did not consider collapse prevention.
3. No regulations regarding restricted entry were in place.
Case 3: Prevention measures
1. Entry into such sites should be restricted.
2. Heavy materials should be piled on stable flooring.
3. Collapse should be taken into account in piling or storage plans.
4. In cases where entry is unavoidable, risk assessment should be implemented and safety should be ensured before commencing work.
 |
Figure 7 (b). Examples of accident prevention measures.
Conclusion
We have analyzed the accidents related to the restoration work during the Great East Japan Earthquake, with a view to prevent future occurrences. The work accidents follow a decreasing trend with the lengthening of time after the earthquake. Falls were the most common type of work accident, affecting 271 people (42.2% of all work accidents).
The illustrations developed and recommendations formulated are designed to facilitate the practical use of the results, particularly for accident prevention measures.
Acknowledgement
This work was supported by Construction Industry Workers' Compensation Friendly Society. The pictures were drawn by cartoonist Shinnosuke Tsuchida. We are gratefully acknowledged here.
References
1. Takahashi, H.; Hori, T.; and Toyosawa, Y; (2013). Causes and measures of work accidents on restoration work of the Great East Japan Earthquake [in Japanese]. Tokyo: National Institute of Occupational Safety and Health, Construction Industry Workers’ Compensation Friendly Society
Papers relacionados
