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 It seems every city has iconic
infrastructure that comes to personify the city itself. The Space Needle,
Golden Gate Bridge and Empire State Building are just some examples. For
smaller or mid-major cities, such landmarks are typically identified only by locals.
A good example is Albany, N.Y.; The Empire State Plaza is quickly recognized by
locals, but few else.
For
Manchester, England, one these landmarks is undoubtedly Beetham Tower, a 554-feet-tall
skyscraper erected in 2006 in the U.K.'s second largest city. Beetham Tower is
by far the tallest building in the city and it looms over the rest of the city's mix of classic and modern architecture. However, Beetham Tower is more
notable for some locals for its audible presence. That is, the tower emits
an audible hum when under a wind load. Here's a YouTube link for
evidence.
The hum is believed to emanate from the
unused section of facade that extends beyond the tower's roof. The skyscraper
was originally designed to be 50 stories tall, but wind load tests showed that
the building would sway too much, so the height was  shortened to 47 stories. The
façade for the tower was already in place, so the last 39 ft. of it extends
beyond the roofline. A decorative glass blade made of louvers were added to make it less unsightly.
When
wind passes over this extension it vibrates and creates a sound that's been
described as a hum, shriek, howl, whistle, or UFO sound. According to Wiki, the sound is close to
the musical note B3 (246.95 Hz) and can be heard by those within about 1,000
feet. The tower houses a 23 level hotel and another 22 levels of apartments.
While these poor blokes (it is in the U.K., after all) have to suffer through
the noise, the architect of the skyscraper, Ian Simpson, lives in the penthouse
apartment at the top of Beetham Tower and probably has to live through the
worst of it.
In 2013 Simpson publically apologized for it and said that he and
his organization were looking for solutions. He admitted that the glass blade
was entirely decorative and could be removed. Yet nearly two years later, Beetham Tower still howls in the wind.
Overall, the howling building phenomenon is
not new.
New York City's Cityspire Tower howled from when it opened in 1990 until
engineers determined that removing every other louver from the building's
cooling tower would eliminate the noisy resonation. The Freedom Tower howled
into the Tribeca neighborhood while it was under construction. Tonal wind
studies are needed to check for acoustic resonance from cavities or structural
resonance from flexible components, but this is a complicated, imprecise and
expensive task. Most of the time buildings or structures create Aeolian tones
completely accidentally.
Nonetheless, I can understand the
distress if these sounds would keep me awake at night too. After nearly a
decade, I think it's time engineers finally got rid of this annoying Beetham
bellow.
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