From a structural engineering point of view, skyscrapers can be designed and built anywhere in the world without mishap or creating hazards, provided that the design engineers have adequate experience and understand the overall behaviour of tall buildings. Of course it is imperative that experienced contractors are available to build the building to the engineer's design.
Dubai is no different from any other location undergoing a major phase of development.
Developers and building control authorities there understand the design and construction issues, and seek expertise from experienced contractors and designers. The magnitude and scale of tall building construction attracts expertise from all over the world.
The focal point of tall building design is the lateral bracing system, but the structural form and gravity framing of skyscrapers also play a major role in their viability both in terms of cost and function.
Optimum structural design solutions must be combined with optimum construction techniques for a tall building to become a reality.
For example, oor plates need to be designed to absolute minimum thickness in order to minimise the overall weight of the building, to get the maximum number of floors, to minimise the foundation and seismic loads, and, ultimately, to control the overall cost of construction.
Unlike low-rise buildings, the repetitive nature of tall buildings means that construction costs as well as any construction issues or problems have the potential to escalate.
For instance, the potential accumulated differential movement of tall building elements, whether due to foundation movement or differential axial deformation of the structure, will reveal itself quite rapidly and prominently.
A differential movement of, say, 50mm in the foundation of a 1,000m tall building could easily lead to a lean of 500mm at the top of the building. If the differential axial deformation of the elements supporting the floors is not properly calculated, then the floors will be uneven by the time construction is complete. And if cores are not constructed to the tolerances specified by the engineer, lifts and stairs will not fit or operate properly.
Buildings in general are vertical cantilevers from ground level, exposed to forces of nature that increase exponentially with height. However, the lateral system, which is the backbone of the structure, must be designed as economically as possible and with minimal impact on the useable oor area.
A badly designed or inadequately constructed lateral system can lead to all kinds of issues in a tall building, such as motion sickness caused by high acceleration or damage to the cladding and glazing, or cracking of the partitions.
Kamran Moazami is director, WSP Cantor Seinuk.