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ΤΑ ΝΕΑ ΤΗΣ ΕΕΕΕΓΜ – Αρ. 48 – ΑΥΓΟΥΣΤΟΣ 2012
Σελίδα 27
Towers in Kuala Lumpur after a seven-year reign as the
world's tallest. In 2010, the Burj Khalifa in Dubai far sur-
passed Taipei 101, climbing up to 828 meters. Bold builders
in China want to go 10 meters higher later this year with a
220-story pre-fab tower that can be constructed in a baf-
fling 90 days. And then, in 2018, the Kingdom Tower in
Jeddah, Saudi Arabia (below, right) will go significantly far-
ther, with a proposed height of at least 1,000 meters.
The Burj Khalifa stands tall in Dubai's skyline -
Reuters.
Rendering of Freedom
Will this race ever stop? Not in the foreseeable future, at
least. But there has to be some sort of end point, some
highest possible height that a building can reach. There will
eventually be a world's tallest building that is unbeatably
the tallest, because there has to be an upper limit. Right?
Ask a building professional or skyscraper expert and they'll
tell you there are many limitations that stop towers from
rising ever-higher. Materials, physical human comfort, ele-
vator technology and, most importantly, money all play a
role in determining how tall a building can or can't go.
But surely there must be some physical limitations that
would prevent a building from going up too high. We could-
n't, for example, build a building that reached the moon
because, in scientific terms, moon hit building and building
go boom. But could there be a building with a penthouse in
space, beyond earth's atmosphere? Or a 100-mile tall build-
ing? Or even a 1-mile building?
The Council on Tall Buildings and Urban Habitat, a group
interested in and focused on the phenomenon of skyscrap-
ers, recently asked a group of leading skyscraper architects
and designers about some of the limitations of tall build-
ings. They wondered, "What do you think is the single big-
gest limiting factor that would prevent humanity creating a
mile-high tower or higher?" The responses are compiled
in this video
, and tend to focus on the pragmatic technicali-
ties of dealing with funding and the real estate market or
the lack of natural light in wide-based buildings.
"The predominant problem is in the elevator and transpor-
tation system," says Adrian Smith, the architect behind the
current tallest building in the world and the one that will
soon outrank it, the kilometer-tall Kingdom Tower in Jed-
dah.
But in terms of structural limitations, the ultimate expert is
likely William Baker. He's the top structural engineer at
Skidmore, Owings and Merrill and he worked with Smith on
the Burj Khalifa, designing the system that allowed it to rise
so high. That system, known as the buttressed core, is a
kind of three-winged spear that allows stability, viably us-
able space (as in not buried deeply and darkly inside a
massively wide building) and limited loss of space for struc-
tural elements.
The illustration in the next page from SOM shows how the
buttressed core of the Burj Khalifa compares to the tradi-
tional structure of the Willis Tower. (This image is an adap-
tation of a graphic that originally appeared in this article
on
Baker and the buttressed core from the December 2007
issue of
Wired
.)
Baker says the buttressed core design could be used to
build structures even taller than the Burj Khalifa. "We could
go twice that or more," he says.
And though he calls skyscraper design "a fairly serious un-
dertaking," he also thinks that it's totally feasible to build
much taller than even the Kingdom Tower.
"We could easily do a kilometer. We could easily do a mile,"
he says. "We could do at least a mile and probably quite a
bit more."
The buttressed core would probably have to be modified to
go much higher than a mile. But Baker says that other sys-
tems could be designed. In fact, he's working on some of
them now.
One idea for a new system would be buildings with hol-
lowed bases. Think of the Eiffel Tower, says Tim Johnson.
He's chairman at the Council on Tall Buildings and Urban
Habitat and a partner at the architecture firm NBBJ, and he
says any really, really tall building would have to be like a
supersized version of the Parisian icon, otherwise the lower
floors required to support the gradually narrowing structure
would be way too big to even fill up.
For a Middle East-based client he's not allowed to identify,
Johnson worked on a project back in the late 2000s design-
ing a building that would have been a mile-and-a-half tall,
with 500 stories. Somewhat of a theoretical practice, the
design team identified between 8 and 10 inventions that
would have had to take place to build a building that tall.
Not innovations, Johnson says, but inventions, as in com-
pletely new technologies and materials. "One of the client's
requirements was to push human ingenuity," he says. Con-
sider them pushed.
With those inventions and the hollow, Eiffel Tower-like
base, Johnson says the design could have worked. The pro-
ject was canned as a result of the crash of the real estate
market in the late 2000s (and probably at least a little good
old-fashioned pragmatism). But if things were to change,
that building could be built, he says.
"We proved that it is physically and even programmatically
possible to build a building a mile-and-a-half tall. If some-
body would have said 'Do it two miles,' we probably could
have done that, too," Johnson says. "A lot of it comes down
to money. Who’s going to have that kind of capital?"
As far as the structure is concerned, others think it's possi-
ble, too. My colleague John Metcalfe recently pointed out a
1990s-era concept for a two-and-a-half-mile volcano-
looking supertower in Tokyo called the X-Seed 4000 that
has a similar Eiffel Towerishness to it.
As Metcalfe notes, this 4,000-meter "skypenetrator" was
never built for a variety of reasons, but the most obvious is
that "real estate in Tokyo isn't exactly cheap. The base of
this abnormally swole tower would eat up blocks and blocks
if it was to be stable." In fact the base of this structure,
according to conceptual drawings, would have spread for
miles and miles, almost like the base of Mount Fuji, itself
about 225 meters smaller than the X-Seed 4000.
