NY Times
A Twisted Path for a Curve-Filled Terminal
By David W. Dunlap
October 7, 2008
(Renderings: Santiago Calatrava/Port Authority of New York and New Jersey)
The latest design shows conical columns added to support the roof — a measure that the Port Authority of New York and New Jersey said would make the structure easier and more economical to build.
The architect Santiago Calatrava has likened his design for the World Trade Center Transportation Hub to a bird.
If so, it has been molting before our eyes.
But it is all for the best, Mr. Calatrava insisted last week, after the Port Authority of New York and New Jersey outlined the design revisions that would make it easier and faster to build the hub. The changes principally affect the enormous underground mezzanine, the completion of which bears directly on the opening of the plaza at the National September 11 Memorial and Museum. “I think it is a good solution,” he said.
But as this series of renderings makes plain, it is a substantially — if subtly — different solution than the one he proposed in 2004, when the mezzanine was to have been flooded in natural light coming through glass paving blocks in the plaza above.
“It will be a lamp of hope in the middle of Lower Manhattan,” he said at the time, “creating an unbroken line of natural light from the platforms to the sky.”
Mr. Calatrava’s “lamp of hope” was anything but that to the designers of the memorial. They envisioned a grove of trees, laid out congruently with the rest of the plaza. “We have to protect the sanctity of the area around the memorial voids,'’ Joseph C. Daniels, the president and chief executive of the memorial foundation, said in 2006. The installation of skylights would have required a bare open area on the plaza, without trees and with its own distinctive paving patterns.
By early 2007, the budget for the transportation hub was evidently well out of control, with the contractor estimating that what was supposed to be a $2.2 billion project might cost as much as $3.4 billion. The Port Authority asked Mr. Calatrava to find ways to save money while salvaging as much of his distinctive design as possible.
The second design removes the structure’s skylights.
first design for the underground mezzanine of the World Trade Center Transportation Hub showed daylight flooding the space through glass paving blocks above the ribbed vaults.
Among the first elements to go — without fanfare or public announcement — were the skylights over the mezzanine. Opposition to them ran up the chain of command at the memorial foundation to Mayor Michael R. Bloomberg, who serves as its chairman. He brought considerable weight to the bargaining table where precious square inches at ground zero are meted out among the many competing projects.
More recently, both the budgetary and scheduling cross hairs fell on the column-free expanse that Mr. Calatrava envisioned for the mezzanine, the central transitional space between the streets above and the PATH passenger platforms below. To create 150-foot clear spans, he had proposed using two enormous rigid trusses (called Vierendeel trusses), on either side of the mezzanine, to support the arched roof structure.
There was growing concern that such complex engineering would jeopardize the ability of the Port Authority to complete the mezzanine in time to turn over the rooftop to the memorial and guarantee that the plaza would be open by Sept. 11, 2011. Once again, Mayor Bloomberg seemed to lead the charge, at least publicly. “The PATH station’s design, including the underground hall, is too complicated to build and threatens to delay the memorial and the entire project,” he wrote in The Wall Street Journal last month. “It must be scaled back.”
In one of the most important revisions by the authority, the trusses were eliminated in favor of more conventional steel plate girders, supported by four columns that would be bolted together rather than welded together. Christopher O. Ward, the executive director of the authority, said the change would eliminate the “substantial risk associated with the original design,” reduce the amount of steel needed by 15 percent, hasten fabrication and erection, and make it easier to construct the roof over the mezzanine. All the same, Mr. Ward said, it preserved the architect’s “iconic vision.”
Mr. Calatrava has designed the columns to taper. “Once we did the renderings, the columns — seen from a certain distance — disappeared,” he said.
It is hard, on the basis of a single rendering, to say whether the new design is a successful accommodation or an unhappy compromise. But it may be hard even for the celebrated Mr. Calatrava to make three-foot-wide columns disappear. This may be a case in modern architecture where more is more.
Copyright 2008 The New York Times Company