Tuesday, August 22, 2006

Why ignore wind? "Unconscionable," says Pratt prof

Anybody who's walked around the Williamsburgh Savings Bank, Brooklyn's tallest building, knows that the wind can be vicious on a winter day. But the Empire State Development Corporation, in producing the Final Scope for the Draft Environemental Impact Statement (DEIS), ignored the call by the Council of Brooklyn Neighborhoods (CBN) to study the effects of wind created by 16 towers and an arena.

CBN had asked:
Wind tunnel effects are already experienced in downtown Brooklyn and can cause problems for pedestrians, particularly people with impaired mobility. The EIS should study and measure wind tunnel effects caused by new construction, and the associated jobs will arise in proportion to the public cost.

Not blowing away

On August 3, the three affected Community Boards held simultaneous public hearings, and Brent Porter, who teaches architecture at the Pratt Institute, told CB2:
No one is talking about the wind impact. If we were a Canadian town or city, all major cities, Toronto, etc., any time a new building that’s three times the heights of its neighbors, it will create tremendous wind impacts. They require that the architectural plans and engineering studies in early days get submitted to proper testing. Our own Rensselaer University upriver does this. I’ve called for Rensselaer or the University of Western Ontario, which is really the primary source for wind tunnel studies, for a project like this--why this was never called for and why the EIS statement says nothing about it, is unconscionable.

Indeed, a British consultancy on wind observes:
Wind effects are an extremely important aspect in the design of tall buildings. Wind loading can often be the dominant load case, with significant increases in loading due to dynamic effects. Dynamic response can also lead to high accelerations which affect occupant comfort. In addition, tall buildings tend to deflect high-level winds down to ground level, affecting the local wind environment at the base of the building

Will FCR do testing?

Even if it's not required under the DEIS, it's likely that Forest CIty Ratner would conduct wind tunnel testing for insurance purposes. As a June 2000 article in Civil Engineering reported:
Wind tunnels provide vital information for a variety of structural designs. Even on more modest buildings, those of 10 to 20 stories, wind tunnel testing is becoming common. "In this day and, with insurance what it is, any building over forty stories will be wind tunnel tested," adds Robert C. Sinn, an associate partner in Skidmore, Owings & Merrill's Chicago office who has worked on many of the world's tallest towers, including the tower proposed for 7 South Dearborn Street.

Note that five of the 16 towers at Atlantic Yards would be more than 400 feet, with a sixth at 397 feet.

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