5.2. Descriptive analysis of fatal tower crane installation/dismantling
accidents
Six fatal accidents that occurred from 2009 to 2011, gathered
from the MOEL database, were examined to investigate causes of
the failures of tower crane installation/dismantling (Table 7). Accident
investigation reports, which contains the results of accident
investigations carried out by labor inspectors of MOEL and technical
experts from KOSHA, were reviewed. These reports describe the
details of accident development, technical forensic investigation
results, probable causes of the accidents, and other issues. The accident
analysis in the present study was evaluated by presenting
three questions, shown in Appendix A, to the focus group
interviewees.
Many causes of fatal accidents were related to installation/dismantling.
For example, accident case B could have been prevented
if workers had followed the procedures in the manufacturer’s manual.
When mast-extension operation was completed, the status of
the central axis of the mast of the counter jib was biased toward
the center of gravity. In this state, connecting pins cannot be
removed. In order to remove the connecting pins, a horizontal jib
should safely maintain balance. Under normal operation, the counterweight
on the hook should be used for balancing by moving the
trolley horizontal jib. The workers, however, did not use the counterweight
at that time of the accident. Instead, they operated the