Anyone who has recently looked up at the Burj Dubai will have noticed that once again the Dubai skyline has changed. The once familiar sight of the cranes nestling on top of the tower has disappeared forever.
During construction of the structure we used three Favco luffing jib cranes which were each specially modified for the Burj prior to their arrival in the UAE to have a lifting capacity of 25 tons.
When installation of these three main tower cranes began four and half years ago they were originally fixed at the bottom part of the centre core with one crane serving each wing of the tower.
All three cranes were self climbing and were jacked in harmony with the structure. At the top of the Burj the cranes and their operators had to endure all kinds of weather such as squally winds of up to 120 km per hour, dust clouds coming from the Northwest, rain and fog and temperatures not far away from freezing point. In general the temperature at the top of the tower ranges between 7 to 8 degrees Celcius cooler than at ground level.
Lifting of reinforcing bar cages, heavy link beams up to 20 tons single weight, shuttering pieces, compressors, hoist masts and machines, custom made elevator motors, concrete placing booms, whatever had to be brought up to support the construction progress of the highest building in the world were lifted up from the ground to the top of the Burj by these tower cranes.
When Level 156 of the tower was reached, one of the cranes had to be taken down, as the concrete works had been completed and the steel construction works did not provide sufficient space for all three of them. So Crane M2 - as it was called on site - was taken down and removed from Site and the two remaining cranes changed their positions.
This change in logistics started on 25th September 2008 and was completed about one month later on 21st October 2008.
During installation of the spire the operators of the two cranes were working in exceptionally high places, and were the source of several e-mail circulars (contrary to popular rumour none of the tower crane operators used on the Project was named Babu). The operator of Crane M3 was working at a height of 688 metres and the operator of M1 was at 708 metres high – two hundred metres higher than Taipei 101 the World’s previous tallest tower!
The pinnacle installation however, was logistically a tricky job with very little storage space and room to manoeuvre. Crane M3 had to give way and was lowered to Level 99 by Crane M1. Although useful for general lifting operations Crane M3 was also one of the recovery cranes which was eventually to be used to dismantle Crane M1.
After completion of the spire works only cladding works were remaining which required access space and consequently the dismantling of Crane M1.
In total four cranes were involved in the dismantling operation: two of the original tower cranes (M1 and M3) as well as Cranes R1 and R2, two recovery cranes which were mobilised specifically for the purpose.
The base of Crane M1 was situated at 560 metres and, as explained above, Crane M3 was located at Level 99. Cranes R1 and R2 were installed at Level 159 (a height of approximately 600 metres).
The procedure used to take the cranes down was very simple yet challenging. A number of mast sections of Crane M1 were taken out, so that the machine deck level came down to Level 159. Crane R1 then took the engine, the diesel tank, the jib and all other components down to Level 99. From there Crane M3 lowered these parts down to the ground on Podium B side. On 9th July 2009 the remaining mast sections were taken down by both cranes following the same procedure.
After Crane M1 was completely dismantled, Crane R2 lowered Crane R1 down to Level 99 where it was used to dismantle Crane M3. After that, Crane R2 was dismantled by hand and also transported to Level 99, via the permanent elevators, where it repeated the process and brought Crane R1 back to ground.
Finally, Crane R2 was again dismantled into small pieces by hand, and brought back to ground level by the Service Lifts BS1 and BS2.