| NYguy |
Jun 27, 2014 12:37 AM |
Quotes from a piece on building tall...
http://www.citylab.com/design/2014/0...ywhere/373493/
Why Can't We Build Skinny Skyscrapers Everywhere?
The limits to how tall and thin towers can be has more to do with markets than engineers.
http://cdn.citylab.com/media/img/cit...lead_large.jpg
June 26, 2014
Kriston Capps
Quote:
Within the next few years, the number of New York City skyscrapers that are 1,000 feet or taller is going to soar. Today, there are seven towers in the 1,000-feet-plus club. If construction proceeds as planned on projects now under way or scheduled to break ground this year, that figure will more than double.
In Manhattan, architects are building highest and fastest in Midtown. There, the supertalls aren't just tall—some of them are superskinny, too. A group of buildings along West 57th Street with residential units priced from $5 million to more than $100 million has transformed the Central Park perch into Billionaires Row, a signifier of America's new Gilded Age. In most cases, each unit is basically its own penthouse suite, occupying an entire floor of its building.
Taken on their own terms, the superskinnies represent a feat of architectural design. The new developments going up on West 57th Street may, in fact, be approaching the outer limits of the tall-to-thin aspect ratio for a structure. Just not for the reasons you might think.
"Structurally, there are a lot of very unique challenges, especially for a building that wants a high degree of special views," says Vishaan Chakrabarti, a partner at SHoP Architects and the director of the Center for Urban Real Estate at Columbia University. SHoP—the firm that designed the Barclays Center as well the forthcoming Domino Sugar Refinery development, both in Brooklyn— is responsible for what may be New York's, and the world's, skinniest supertall.
.....Down the road is 217 West 57th St., another supertall, superskinny Midtown tower. This isn't, strictly speaking, the project with the sharpest aspect ratio that architect Gordon Gill has ever designed. That honor belongs to the trident-shaped tower designed by architecture firm Adrian Smith + Gordon Gill for One Dubai in the United Arab Emirates, a $95 billion—billion—mega-development planned by firm Skidmore, Owings & Merrill (SOM). But 217 W. 57th St. will nevertheless be one of the skinniest towers in Manhattan and the nation.
"The complexity just increases when you get slender," Gill says. "The floorplates become smaller, but the views can become really amazing."
.....This new kind of skyscraper is popping up all over Midtown—but so far, only there. There are reasons that superskinnies haven't shown up in Chicago, Los Angeles, San Francisco, Dallas, or other cities. Nor are they likely to get much skinnier in Manhattan.
"From an engineering standpoint, there’s a ways to go," Gill says when I ask him how tall and thin the firm can build. "From an economic standpoint, we’re close to the limit."
....."We cut slots, we punch holes, we create notches in the corners of the buildings" to mitigate the effects of wind, Gill says, on tall and thin buildings alike. But there are some places where superskinnies will just never go. No matter how pitched income inequality comes to be in San Francisco, these towers will never rise there. "For areas that are seismic, the slenderer buildings are not advisable," Gill says.
.....Even in Billionaires Row—where Midtown zoning allows skyscrapers to soar—the oxygen has mostly been used up. To build the towers that are rising now, in many cases, developers purchased air rights from adjacent shorter buildings. "At least in this corridor, most of the air rights have been used up," Chakrabarti says.
In other words, these superskinnies are unique—a "registration of the market," as Chakrabarti calls them. "It is a typology that’s happening, no question," he says, noting that SHoP has at least two more supertalls coming to New York.
"But if I look at our overall portfolio, [superskinny, supertall] is not an enormous percentage in terms of square footage."
So fans and critics of these buildings shouldn't expect to see them copied everywhere. At least, not until design and engineering technology advances to the point that that the aspect ratio can be pushed to even leaner proportions in markets that could sustain these developments. Or, not until other markets generate the political climate that makes these developments possible.
"I just received a document a couple days ago from someone who's been working on a patent for building stabilization," Gill says. "I'm going to dig into that and check that out. The more we learn about how to tune that, the more interesting the structures can become."
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