yep portage uncle.. heard it on the news the other day when they were reporting on its grand opening.. here is an excerpt form the BBC news item..
Mohamed Ali Alabbar, chairman of Emaar Properties, the developer behind Burj Khalifa, told the BBC that the building's design had posed unprecedented technical and logistical challenges, not just because of its height, but also because Dubai was susceptible to high winds and was close to a geological fault line.
Just for reference, here is an illustrative comparison of some of the world's tallest sky-scrappers with burj-khalifa:
Source