They're Finally Building the World's New Tallest Tower

For three years, the fate of Saudi Arabia's Kingdom Tower has hung in the balance. Originally conceived in the heady days of the 2000s, the project has gone through multiple delays and redesigns since 2008. Now, its final iteration—at one kilometer tall—finally been given a start-date for construction.

They're Finally Building the World's New Tallest Tower

Workers at the tower's site, in Jeddah, started driving huge foundation piles 330 feet into the sand last year. But it was unclear if the building itself would ever emerge—or if, like Chicago's Spire, it would remain a gaping hole in the middle of the city. Here's what work at the site looked like in 2012:

They're Finally Building the World's New Tallest Tower

Image: Azam, user of the aqarcity forum/Skyscraper City user patrykus.

According to BD Online, the $1.2 billion project is officially back on. Investors have set a starting date—April 27th—and have chosen a construction manager: the UK companies EC Harris and Mace, which will jointly run the project. Mace is the same company that managed construction of Renzo Piano's Shard, in London.

But there are plenty of unanswered questions about Kingdom. Amazingly, no one is quite sure how living at 3,000 feet will affect humans. It's also unclear how elevators inside the building will work, since the current weight of elevator cable makes it impossible to support above roughly 2,000 feet.

They're Finally Building the World's New Tallest Tower

Image: CTBUH.

In an interview with Bloomberg, Gordon Gill—one half of Adrian Smith + Gordon Gill Architecture, who designed the tower—had the following to say about the unknowns:

There may be a limit to the rapid change in height the inner ear can stand. At extreme heights, an elevator might need to be designed to go slower than one might want, or to rest at a middle floor. But that's not something condo buyers are likely to favor. Asked if he's ever worried about the discovery of an unforeseen challenge or phenomenon only after a tower has topped out, Gill smiles, pauses, and says simply: "Yeah."

But all of those uncertainties are exactly why supertall construction is so interesting: We can do as much research and testing as we want. But ultimately, we won't know until we try. [BD Online]