Identification and assessment of human errors among tower crane operators using SHERPA and CREAM techniques

Cranes are of the major causes of accidents in the construction industries. As human error mostly causes crane accidents, this study aims to investigate the human errors of tower crane operators in the construction projects using SHERPA and CREAM techniques.

In this research, first, all of the tasks of the tower crane operator were identified and analyzed. Then, adopting SHERPA technique, probable operator errors were identified in each task and the control modes and error probability were determined by CREAM technique. Finally, all the human errors risks were assessed and the actions for risk control were defined to control them in the acceptable level.

According to the SHERPA technique, 148 errors were identified in the crane operator tasks. The human error assessment showed that monitoring the anti-collision system with the risk probability of 0.0003 has the highest control factor, while monitoring the existing guards with the risk probability of 0.056 has the lowest control factor. Also, the important tasks with high human errors were monitoring the guards with the cognitive risk probability of 0.07 and the tasks with cognitive risk probability of 0.05.

The findings in this study indicated that using complementary qualitative and quantitative methods can provide identification and prioritization of identified errors. This can help the organization   to allocate limited organizational resources to control unacceptable risks and increase the efficiency and effectiveness eventually.