DIALOGUE: On top form

Martin Horlesberger, project manager for high-rise projects, Doka.

What was the scope of the work Doka you carried out during your involvement with the Burj Khalifa?
Doka designed and delivered a self climbing system for all centre core walls and wing walls of this structure. We provided supervision during all stages of assembly and set-up of the system, as well as certification of the product, and training of the operators.

The top priority was to make the system work for all logistical requirements, such as direct access from hoists onto the work platforms of the wall formwork, and separation of work-zones for continuous flow of all activities within the fixed three-day per floor cycle.

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How many climbing and support systems and platform levels were used?
We provided over 5000m² of self-climbing wall formwork and four climbing and support systems for concrete placing booms (incorporated into the hydraulic climbing of the wall formwork).

We also supplied around six platform levels within the climbing system to enable optimal access of all trades e.g. installation of pre-assembled two-storey high rebar cages, MEP installation, pouring of concrete, operation of hydraulic climbing system, concrete finishing works, etc. In addition, we designed and provided an exterior enclosure screen for slab works.

What made working on the Burj Khalifa different to any other development?
At the Burj Khalifa, the amount of wall formwork to be handled per floor was around twice the amount of slab formwork; at any other typical high-rise building, this ratio would be the other way around. 

There were a large number of changes to the climbing system in the design layout, which had to be made very quickly, without effecting the cycle-time of ongoing floors.  

Due to height of structural concrete, the climbing system needed to be able to cope with 200km/h winds and all necessary ‘infrastructure’ had to be incorporated into the climbing platforms e.g. site offices, rest areas, toilets, fresh water, etc. This allowed the work force to stay up on the top of the tower for one full shift without having to come down.

What lessons did you and your team learn from the working on the project?
Safety systems provided e.g. all platform enclosures and screen systems for slabworks allow maximum speed of construction, even at extreme heights. Also, all systems have to be flexible to changes in layout and must consider MEP work access and crane climbing sequences.

Future designers will prefer more complex structures versus straight-forward boxes and, finally, we learned that direct on-site assistance and communication with the contractor, throughout the entire construction period, is critical.

What challenges did you face during the development of the project?
Wall formwork, measuring 1.25km, had to be implemented on a three-day per floor cycle. This included hydraulic lifting of the climbing system, rebar installation, plumbing, pouring and curing.

We had to manage our logistics so the workforce had safe access to the climbing system at the top of the tower and the system had to cope with shifting during the construction stages.

Martin Horlesberger biography:
Hoerlesberger has worked for Doka for the last 23 years. During this time, he took on the role of engineering manager for branches in Austria, Singapore, Malaysia, Kuwait and the US and, 17 years ago, he began to specialise in high-rise projects using automatic climbing systems.

He is now the project manager for high-rise projects and has managed developments such as The Heritage Tower and 55 East Erie Tower in Chicago, Illinois and Palms Hotel and Casino in Las Vegas, Arizona, before working on the Burj Khalifa.