Sydney Airport Control Tower

Steel lights up Sydney air traffic

As air transport has become more elaborate, the traditional squat brick control towers have evolved to taller steel frames and, in the most familiar form, tall cantilevered concrete shafts with a large bubble on top, using the technology of water towers. 

In designing for Sydney, this convention was challenged. A cantilever out of the usually swampy ground of airports and another cantilever at the top encourages sway, while the massive loads of water towers do not apply. As there must be a lift, services and emergency stairs, the shaft is grossly oversized for the loads involved.