In January 2018, a 25 tonne articulated crane (a 'pick and carry' type mobile crane) overbalanced and fell across four lanes of a major arterial road while it was lifting a sign. Three lanes of traffic were closed at the time and there was no traffic in the open lane.
The crane was removing a signage structure 15m in height, 3.9m wide and weighing approximately 4.5 tonnes. While manoeuvring, it appears the load caught on a structure then swung toward the road. Nobody was injured and investigations are continuing.
Preventing a similar incident
Incidents have occurred where mobile plant, such as articulated cranes, has overturned with the potential for serious injury from being struck, pinned or crushed.
A mobile crane is likely to overturn if it is outside the stability area of its load chart. The stability area of the load chart shows how much the crane can lift without affecting the stability of the crane. Other factors that may affect the stability of the crane include:
- poor ground conditions such as unstable ground
- slope and side slope of the ground
- failure to use or fully extend outriggers or stabilisers
- failure to level the crane
- rapid slewing
- high wind conditions.
Cranes and mechanical lifting gear are used to handle heavy loads and it is important to select the appropriate plant for the task. The lifting capacity of a crane is limited by:
- structuralstrength when the working radius is small
- stability when the working radius is greater.
PCBUs must ensure:
- effective planning for the task is undertaken prior to work commencing
- when estimating demolition loads to be lifted (i.e. for plant and/or materials), a suitable factor of safety should be included to allow for any inaccuracies
- the travel path of the crane should be solid, flat and, clear of any debris and steps
- the appropriate crane is selected for the work task (i.e. a slewing mobile crane on outriggers may be more suitable)
- if the work is high risk construction work then a safe work method statement must be prepared prior to work starting
- weather and ground conditions have been assessed
- the manufacturer's operating instructions have been read and are followed. For older items of mobile plant where operating instructions are not available, operational procedures and instructions for use should be developed by a competent person
- training is appropriate for the type of work being performed
- pre-operational checks are carried out prior to each work shift
- routine inspections and maintenance are carried out in accordance with the crane manufacturer's instructions
- ten year major inspections are conducted in accordance with AS2550.1: Cranes, hoists and winches – Safe use – General requirements
- a crane service record, such as a maintenance logbook, is kept and readily available.
Crane operators must:
- have a comprehensive knowledge of the operating capabilities of the crane
- be competent to carry out the lifting operation
- ensure it is driven to suit the environmental conditions and slow enough to retain control in unexpected circumstances
- reduce speed before turning or applying brakes
- watch out for ditches, embankments, ground depressions as overturns can occur
- ensure loads are evenly balanced and well secured.
The dogger is responsible for safely slinging the load and providing accurate directions to the crane operator on load movement to ensure crane's stability.
Since, 2012, there have been 9 workers' compensation claims accepted for injuries caused by a crane rollover. During the same period, 15 improvement notices and 7 prohibition notices have been issued for incidents involving crane rollovers.
Prosecutions and compliance
In 2014, a company was fined $45,000 and a further 12 month surety of $10,000 after two workers received serious injuries when the elevating work platform (EWP) they were working in overturned. The two workers were tree trimming from the bucket of the EWP at a height of approximately 6 metres when the truck overturned and caught on power lines. One worker fell and landed on a nearby roadway and the other managed to remain in the EWP's bucket. The truck mounted EWP was a type not previously used by the company, and, although the two workers had the appropriate qualifications, neither had read the EWP's operation manual. The truck was set up incorrectly resulting in it being insufficiently stabilised.
In 2012, a five tonne over head gantry fell from its running rails and crashed onto the floor. A person below the crane was trapped and sustained serious crush injuries to his torso. This matter is currently before the courts.
Mobile Crane Code of Practice 2006 (PDF, 1.34 MB)
Steel construction Code of Practice 2004 (PDF, 1.12 MB)
Tilt-up and Pre-cast Construction Code of Practice 2003 (PDF, 0.96 MB)
Tower Crane Code of Practice 2017 (PDF, 1.56 MB)
Formwork Code of Practice 2016 (PDF, 1.32 MB)