Known for its extensive investment in land reclamation, aggressive development, and magnetism for foreign labour, Dubai has arguably been one of the most exciting places in the world for the forward-looking structural engineer. In fact, the United Arab Emirates as a whole seems to be obsessed with doting on its plethora of ever-increasing metropolises. Like many mature cities such as New York, Tokyo, and London, however, the challenge facing them isn’t “Can we do this?”, but “Where?” As the world’s 116th largest country, UAE has taken to looking upwards, rather than outwards in recent years. And where necessity dictates, creativity and engineering limits are pushed to higher plains as a result.

The Burj Khalifa won the title of World’s Tallest Building (2,717ft) when it was inaugurated on 4th January 2010. (Among its other records is the Building with the most floors [160], World’s Fastest Elevator [64 kmh], and World’s Highest Mosque [158th floor]) Supporting the colossal structure is a foundation of 45,000 m3 of reinforced concrete, weighing more than 110,000 tonnes (long). In total, 330,000 m3 of concrete and 55,000 tonnes of steel were used to construct the entire project. Oh, and it took 22 Million man-hours to turn this pile of ashes into the towering phoenix that now overlooks Downtown Dubai.

With any project looking to push the vertical limits of construction, Burj Khalifa was not without its problems. Due to the presence of corrosive materials found in the local water supply, a cathodic protection system had to be installed in order to safeguard the integrity of the steel reinforcements. In addition to this, SOM were contracted to carry out creep and shrinkage testing in order to analyse how the stress of 110,000 tonnes would affect the structure. Whilst this is a standard requirement for constructions of this type, when dealing with buildings on this magnitude, extra caution needed to be taken. It has been estimated that over the course of several decades, the structure could actually reduce in height by up to two feet. That doesn’t sound a lot, but for structural engineers this could be a reality which could result in catastrophe if structural movements weren’t worked into the design.

As a material, concrete is unique in its shrink and creep properties. And there isn’t much that can be done to stop it. Because of the building’s inherent design, much work was carried out to inhibit the effects of differential shortening. Using computer models to test out feasibility, a structural surveyor team and architects worked out where stresses were likely to occur, and developed a design which matched the gravity stress of the perimeter columns with the interior corridor walls. By developing  special joints and allowing for larger gaps in the walls, as well as reducing any future movement would have minimal impact on services such as water, electricity, communications, and that all important cooling system. Through careful geometric alignment, the Burj Khalifa benefits from strong lateral and torsional tolerance, meaning this behemoth will be around for a long time to come.