Burj Khalifa – Conquering the Skies
The Burj Khalifa, or Burj Dubai as it was originally known, is a legendary building that can only be described in superlatives. At over 828 metres high, it is the tallest building in the world; with 160 stories, the Burj Khalifa has the most stories of any building in the world, it also has the highest occupied floor in the world, the highest installation of an aluminium and glass façade, the highest nightclub and the highest restaurant, the tallest service elevator and the elevator with the longest travel distance. Finally, it also has the highest revolving doors ever installed in the façade of a building.
In less than 30 years, Dubai has become a leading city in the Middle East that has become well known for the architectural, constructional and engineering feats it achieved. The Burj Khalifa has become the symbol of that progress. Fittingly the Burj Dubai also brings back the title of tallest man-made structure in the world back to the Middle East where the Great Pyramid of Giza was one of the first to hold that title over 4 millennia earlier.
The tower was designed by the architectural firm of Skidmore, Owings and Merril which is well known for their designs of the Willis Tower (formerly known as the Sears Tower) and the new One World Trade Center in New York. The three lobed design was based on the Hymenocallis flower and consists of three elements arranged around a central column, with the elements shifting in a spiral pattern as the height of the tower increases. That this was truly an international project, is best showcased by its construction team consisting Samsung Engineering & Construction of South Korea in a joint venture with Besix from Belgium and Arabtec from the United Arab Emirates. The consulting firm of Hyder Consulting from the United Kingdom was responsible for overseeing the engineering integrity of the building. Overall companies from more than 30 different countries helped to make the Burj Khalifa possible.
A Windy Challenge
When building a skyscraper this size, wind loads are a major difficulty that has to be overcome. Without additional measures the top of the building could start swaying so much in the wind that people inside might get seasick. Dubai moreover is plagued by the Shamal; sand storms that can last for days. With a façade containing as much glass as the Burj Khalifa’s, withstanding these weather conditions would be challenging. The three lobed design however proved to bring a solution as the spiralling floors break the wind flow around the building resulting in a sound and stable structure.
The Highest Revolving Doors in the World
The design of Skidmore, Owings and Merril called for an outside observation deck on the 124th floor of the building with two glass revolving doors granting access to it. At 442 metres high, these would be the highest revolving doors ever installed in the façade of a building and had to be able to withstand wind loads of at least 3000 Pascal, or an F3 class Tornado. The Burj Khalifa required two automatic revolving doors with a diameter of 3000mm and an overall height of 2700mm, the canopy could be only 300mm high with the motor being installed on top of it. Normally a revolving door with these specifications would only be able to withstand wind loads of up to 689 Pascal: It was clear that not every revolving door manufacturer would be able to supply an entry that could meet these requirements.
Meeting the Challenge
Royal Boon Edam was one of only two companies invited to come up with a solution for this challenge and our engineers met it head on. We knew that there were two main problems to overcome: the curved walls of the revolving door would have to be strong enough to withstand the winds and the door set would have to be fixed tightly in order for the door wings not to be blown loose during a storm. Boon Edam worked closely together with Mace the Hyder Consulting, Samsung Engineering and Construction and Turner Construction, the subcontractor, to develop a solution that met all requirements. During the initial phases of the process, the second company that had been invited to tender for this project had to drop out as they could not get their design to work in the challenging conditions on the 124th floor. Boon Edam persevered and after carrying out different wind load and glass tests, managed to adapt the construction of their Tourniket revolving door to meet the requirements of the Burj Dubai.
A Revolving Door Able to Withstand a Tornado
The proposal we came up with was a Tourniket revolving door with specially reinforced posts that are twice as wide and thick as those of a normal revolving door. These were firmly bolted to the floor with special bolts being used underneath the floor to ensure the strength of the structure. Although most revolving doors are installed on top of the flooring, this one was placed underneath the final layer of concrete floor of the observation deck. In order to guarantee the stability of the door set, an extra thick steel frame was integrated into the construction. This allows the door wings to easily withstand the wind pressures.
Special Projects Based on Standardised Solutions
The revolving doors we created for the Burj Khalifa posed an incredible challenge. The experience and expertise of our engineers combined with the proven technology of the Tourniket revolving door allowed us to meet it and bring it to a successful conclusion. Today both revolving doors are used on a daily basis to allow visitors a spectacular view of Dubai. Their glass construction compliments the modern façade of the observation deck and puts the stunning skyline of Dubai in the spotlight where it should be.