By Sarah Blackman
The Burj Khalifa is finally open to the public, but just what will it take to power this mammoth structure? CW talks to Hyder Consulting project director John Mills to find out the answer.
The Burj Khalifa is finally open to the public, but just what will it take to power this mammoth structure? CW talks to Hyder Consulting project director John Mills to find out the answer.The international press may have critisised the double delay of the world's tallest building, but was the media right to judge or did they simply not realise the sheer scope of the work that went into creating such a mammoth structure?
Believe it or not, even looking up at the Burj Khalifa, it can be easy to underestimate the scale of construction involved in the project; it is not common knowledge, for example, that 175km of water pipes (for chilled water and plumbing) were installed, which, if stretched out in a straight line, could cover the length of Dubai, from Sharjah to the border of Abu Dhabi, 2.3 times.
"The biggest challenges were overcoming the complexity and scale of the many interfaces of the project," says Hyder Consulting project director John Mills.
As design consultant on the project, Hyder's role was to certify and adopt Skidmore, Owings and Merrill's design, including structural design, MEP work, facade design, architectural base-build, peer review and master planning and infrastructure design of Downtown Burj Khalifa.
Hyder provided construction supervision of around 12,000 men during its involvement at the Burj - a daily logistical test for the company.
The firm also had to take the building's ability to cope with severe wind conditions into account.
"Extensive wind tunnel testing took place during design and construction. Hyder also instigated physical building movement testing during construction, verifying correctly the designed building behaviour," says Mills.
So how will the building be maintained post construction? According to Mills, monitors have been installed to detect movement of the building now it has been completed and plans for cleaning the building have already been mapped out.
"Facade cleaning of the tower is carried out from cradles suspended from building maintenance units. The podium level is cleaned from a cradle attached to telescopic arm machines and abseiling techniques are needed to clean 50m at the top of the building," he says.
Each ‘cleaning' of the Burj will take around eight to 12 weeks to complete.
In terms of electricity, the total connected load the building can manage at one time is 80MW - enough to power 1.3 million 60W light bulbs. The maximum demand load at any one time is estimated at 40MW to 45MW, but this can vary dependent on the level of occupancy inside the tower.
A district cooling plant will deliver cold water to the building and keep it cool and, to be as sustainable as possible, the building's chilled water system is a closed loop, with pumps circulating the chilled water at the rate of 1200 litres per second.
"In order to minimise pump pressures there are further heat exchangers situated at plant rooms within the tower. This water does not go to waste," insists Mills.
In addition, the condensate that is produced as a result of the cooling - enough to fill 20 Olympic-sized swimming pools - will be used to irrigate the park and water features that surround the Burj Khalifa.
The tower may be kept cool, but, according to recent reports, serious problems could be created as the temperature drops towards the top of the building.
A German newspaper stated that the temperature at the pinnacle of the structure is eight degrees lower than at the base, meaning that, if a door was opened at the top of the building and at the podium level, as well as air locks in between, a storm could rush through the tower and destroy everything in its wake.
Mills confirms that the effect described by the paper is genuine but says there is no cause for concern. "It is called a stack effect. Hyder has carried out separate research to try to harness the power, which could be generated by this. The effect has been recognised on the Burj Khalifa and engineered out using air locks, which cannot be opened continuously."
Implementing air conditioning systems, electrical power and wind provisions were just a few of the many tasks that had to be ticked off the job list at the Burj Khalifa construction site.
Outsiders may not have realised just how long that list really was.