According to available literature, safety at work and productivity of cranes are
a necessary and insufficiently researched topic. Both research directions are
closely related because they depend on the number and type of stoppages that
occur during operation of these construction machines. The focus of research
should be on identifying the stoppages that can have fatal consequences for
employees on-site, or unintended consequences in terms of production loss, means
of work, or environment. In the present research, an attempt is made to create a
methodology for identification, analysis, assessment, classification, and
calculation of stoppage risk in cranes (classified by categories and causes).
Criteria used for analysis, assessment, and calculation of stoppage risk: degree
of stoppage danger, frequency of stoppage classified according to stoppage
categories/causes, and downtime according to the adopted classification.
Experimental research on a sample of 1,091 stoppages recorded on several cranes
over a longer time interval has confirmed the hypothesis of generating a
3-criterion matrix for stoppage risk assessment sensitive enough to prioritise
key crane stoppage in terms of risk. Results of experimental research indicate
mechanical downtime of 16.22 %, a frequency 45.35 % in downtime, and RPN number
80, at hazard level 10. Selectively, according to the cause of stoppage, the
results indicate that the hoisting brake (6.48 % downtime at hazard level 10;
2.14 % stoppage frequency) and hoist gear/tooth breakage (5.29 % downtime at
hazard level 10; 3.58 % stoppage frequency) are key mechanical causes of
stoppages and crane risk generators. By mitigating the given risks, it is
possible to improve safety and increase productivity.
Keywords: crane, risk assessment, stoppages, downtime analysis,