The 2015 Mecca crane collapse is still fresh in everybody’s minds. In the late afternoon of 11 September 2015, a crawler crane manufactured by Liebherr collapsed on the Grand Mosque killing more than 100 people and injuring hundreds of others. The crash was initially blamed on bad weather, but government investigations later revealed that weather warnings were ignored and safety regulations were not followed by the construction firm Saudi Binladin Group.
Liebherr conducted its own detailed investigation by sending crane experts to Saudi Arabia and came up with the following findings. The Liebherr LR 11350 crane was erected at the time of the accident with a boom length of approximately 190m, parked outside of the Grand Mosque and put out of operation. Previously it had sporadically been used for assembly works. On the day of the accident, a strong thunderstorm and sandstorm with measured wind speeds of 80km/h (according to the CNN Weather Service) and 105km/h (wind recording of a Liebherr tower crane near the place of accident), along with heavy rain falls and a sudden drop in temperature by 20⁰C, the crawler crane was caught by the wind and tilted over the last support rollers of its crawler tracks. The operating instructions of the LR 11350 and the associated wind speed charts showed that the crawler crane could not withstand such a high wind load and that the boom should have been lowered to the ground preventatively to avoid the tilting of the crawler crane.
Several recent crane accidents have put the spotlight again on tower crane safety. The Grand Mosque in Mecca witnessed another crane collapse in May 2018 when the arm of a mobile crane toppled to the ground and injured the driver. This time, the cause of accident was weight overload.
Two major crane accidents were reported this year in the UAE. In March 2018, a crane collapsed in Sharjah killing a worker. In the same month, a tower crane collapsed in Abu Dhabi crushing parked vehicles below.
All these cases show a glaring lack of safety mechanisms on construction sites. Extreme weather, particularly high wind speeds, will always remain the biggest enemies of tower safety operators. But cranes are also designed not to crash or tumble within their operating limits, which are specified by manufacturers in their operating instructions.
The biggest conversation the construction industry needs to have about cranes is safety and training. Contractors and operators now have every technology and tool at their disposal to minimise human error
