By Nathan Silver
Photography By Sean Hemmerle
December 2001
Though the WTC was originally unpopular, the courtyard
(above and below left) and restaurants, such as Windows on
the World (below right), helped New Yorkers to accept the
hulking complex.
Lost New York, my 1967 book about the city's vanished buildings, was republished
in a revised edition in the summer of 2000. Reviewing it in the New Yorker,
Paul Goldberger remarked on the deletion of a "Landmarks in Danger"
chapter. "You couldn't make a similar list of important buildings in
danger today because there aren't any," he said.
I had partly replaced that chapter with stories and images of New York buildings
that continued to exist but had had pivotal episodes in the past. Chillingly
one of my new entries was the 1945 airplane crash into the Empire State
Building, which killed 14 and injured 26. Another was the Triangle Shirtwaist
fire of 1911, in which 146 young women died, many jumping from the
ninth story as a horrified crowd watched. A year later New York has
lost its most prominent landmark by plane and fire, with victims too
high to reach and casualties of a magnitude larger than any in building
history.
In memoriam, what should be said about the World Trade Center? First, it
was certainly a landmark: the silvery twin towers had grandeur, rising through
Lower Manhattan twice as high as anything around them. Second--alas, it
had no other impressive architectural feature to place second. Indeed, if
the WTC had instead been demolished to make way for a more conspicuous megadevelopment,
it would be noted mainly as the tallest pair of buildings yet to disappear.
But it would not be as ennobled as an earlier, more distinguished "world's
tallest" titleholder that vanished in 1966, the 47-story Singer Tower.
(Completed on Broadway at Liberty Street in 1908, it was the cynosure of
all early-twentieth-century skyline photos.) As for notably brief duration,
the 20-story Gillender Building, on Wall Street, was finished in 1897
and demolished little more than 12 years after completion; the WTC by comparison
had an almost reasonable New York life span of about 31 years (it opened
in stages from 1970 to 1973).
Architect Minoru Yamasaki of Detroit designed the seven-building WTC complex,
by far his most important commission, with Emery Roth & Sons as consulting
architects; the structural engineers were Worthington, Skilling, Helle and
Jackson. They produced a required 10 million square feet of office
space mostly within the twin towers. The slim rectangular prisms had to
be girdled by so much structure that the exterior wall openings were articulated
as narrow pointed "Gothic" windows, in the arbitrary manner of
ahistorical expressionism that was popular with many architects in the early
1960s but hated by the more progressive architectural critics. Its main
functional innovation was the special elevator bank, developed by Otis Elevator
Co., of express and local cars with "lobbies in the sky" for changeovers,
which reduced the area needed by piggybacking three sets of elevators one
above another. Externally the disliked windows were so narrow that from
a distance the towers looked windowless, which rather grew on observers
when the era of minimalism arrived. Viewed from afar, the buildings displayed
geometrical restraint in contrast to others around them. Internally the
106th and 107th floors of one tower had exciting restaurants and cafés
with spectacular views.
The World Trade Center's steel-mesh exoskeleton necessitated
long, narrow windows (above) that were virtually
invisible from the exterior.
That would be about it for major architectural interest. The WTC scored
in other respects with the towers' convenient siting at a transit node and
the economical straightforwardness of their structural design. These haplessly
contributed to the death toll when the inconceivable attack occurred.
Most twentieth-century skyscrapers were built as cages. The airplane that
accidentally flew into the Empire State Building crashed into a partly redundant
jungle gym of support elements. Those enabled the skyscraper to survive
the collision of a 1940s warplane with relatively low speed, weight, and
fuel capacity; afterwards, little structural refabrication was necessary.
Some other tall buildings have been designed with treelike structures, including
Frank Lloyd Wright's unbuilt but exemplary Mile-High Illinois Tower.
Architectural firm Mancini·Duffy's 150-person office (above)
was located at Two World Trade Center.
In contrast, the WTC was designed like a pair of stiff zippers. The 110
floors of each tower could bend in the wind but stay aloft because floor-high
teeth of steel and concrete--braced to secondary central supports--surrounded
the building, gripping it together. On the heartbreaking day that commercial
jets heavy with fuel crashed into the towers, they just unzipped. First
the collisions took out sections of columns while the explosions blasted
away other steel parts' fire-protective sheathing. Then the combusting
remains of the fuselage and wings amid the superheating fire of aviation
fuel brought the remaining columns to a temperature past their "yield
point," at which structural steel disastrously loses most of its strength.
Finally, as the weakened intermediate floors--bearing the huge load of floors
above--began to smash down and overload unweakened floors below, the towers
gave way completely in a textbook "progressive collapse." They
crumpled in concertina fashion, probably sparing many lives by not falling
sideways. The structural designers' risk assessment had never conceived
of terrorist engineers running a counterdesign to find the best way
to destroy them--nor dreamed of suicidal hijack pilots.
Twice as tall as anything in the Lower Manhattan skyline
(above), the twin towers were the city's most
prominent landmark.
Following the cataclysm, structural engineers have been conferring in crisis.
We can expect that if similar attacks occur in the future they won't be
as devastating, if only because the WTC disaster will undoubtedly reduce
the heights of skyscrapers to come. Cautious new planning codes won't necessarily
be the constraint: as real estate, very tall buildings offset their premium
construction costs with income from tenants prepared to pay high rent for
the topmost floors. It may be years before people are again willing to be
elevated above the clouds (and if that proves true, primary urban form will
change). We can also be sure that the fire safety of tall buildings
will become more effective. Designs with redundant structural elements may
reappear, such as cage grids superimposed on tree configurations. Evacuation
elevators may become compulsory, with heavily reinforced shafts, protected
high-strength cables, and cars that are remotely powered. Building and occupancy
codes may start to cover not only means of escape and the location of hose
reels, but the matter of educating safety officers and firemen
about the possibility of collapse in the structures they look after. Finally,
public resolve following the 2001 WTC disaster should be expected to radically
improve the security of very tall buildings, just as public outrage following
the 1911 Triangle Shirtwaist fire revolutionized labor laws and led
to the regulation of safety in sweatshops.
