The New York Times Co. has made it as clear as the ultra- transparent glass on Renzo Piano’s 52-story office tower for the media giant’s midtown Manhattan headquarters: An educated “consumer” can be heaven for the design team and just the opposite for the construction manager.
The Times and its local development partner, Forest City Ratner Cos., gave the designers the coveted luxury of three years’ time to pore over the details of the high-profile project’s unusual components, from the light gray, horizontal filigree sunscreen that masks the 650,000-sq-ft facade to the outdoor-steel exoskeleton. Between October 2000, when the owner announced Renzo Piano Building Workshop with FXFowle as its architect, and November 2003, when the local AMEC Construction Management Inc. was signed on as CM, the owner held expert-advice summits, built mock-ups and arranged for studies to inform its team.
Nadine M. Post/ENR
Thurm bid the construction manager�s contract.
“If you are going to innovate, you have to become an educated owner,” says David A. Thurm, the Times’ senior vice president for the building.
Without being specific, Thurm says the Times made a “significant” capital investment to control costs. Summits were convened on materials, including terra cotta for sunscreen rods and wood for lobby flooring. Studies were done on daylighting and air-flow. The Times even built a quarter of its office floor to study the work environment.
“Everything we did was cost-justified,” says Thurm. The result is an “extraordinarily complex job...that was basically affordable,” he adds.
The Times also developed purchasing methods to take the fear factor out of bid prices for the tower’s unusual systems. This included paying four competing curtain wall suppliers $50,000 each to build a mock-up of several sunscreen units. Not only did the design team learn from the exercise, bids came in 20% below estimates that already were high.
|Curtain wall’s appearance changes depending on view angle, sun’s angle and interior lighting.|
Another mock-up helped slash $4 million off the estimated cost of the open stairways that interconnect Times’ office floors. The exercise even improved the stairway’s looks, says Thurm.
The process thrilled the designers. Daniel J. Kaplan, senior principal for FXFowle, New York City, calls the tower a “Greek temple in the service of commerce,” with “purity and geometric rigor” in its architecture.
The mechanical-electrical-plumbing engineer is equally into it. “The Times wanted to explore technologies to improve the building” which is not the norm, says David B. Cooper, president of the New York City office of Flack+Kurtz, a WSP Group Co.
Thomas Z. Scarangello, a managing principal of local structural engineer Thornton Tomasetti, adds: “We had the rare opportunity to study options, and, almost every time, we went with the third or fourth iteration. Most projects barely get past the first or second.”
But what is good for the goose is not always good for the gander. The long design phase resulted in a full set of bid drawings. That had serious ramifications for AMEC, which had been providing preconstruction services since 2000. “It’s been real tough,” says Patrick Muldoon, AMEC’s senior vice president. Things began to unravel in mid-2003, when AMEC learned the owner was going to competitively bid the guaranteed maximum price contract for the 1.6-million-sq-ft building.
“It was a big contract and it was a good climate to buy,” says Hussain Ali-Khan, Times’ vice president for real estate development. “We didn’t negotiate because we had a solid set of drawings.”
Muldoon was unnerved. But in the post-9/11 buyer’s market, “We were hungry, so we took risks,” he says.
AMEC won the bid with a price of $350 million. But it has become a Pyrrhic victory. “We gambled and we lost,” says Muldoon.
The biggest misstep was the choice of a joint venture of Interstate Iron Works Corp. and Havens Steel Co. for the $75-million steel contract. “There were more experienced players than Interstate, with better track records, but we had a comfort level because Havens had a strong balance sheet,” says Muldoon.
But in early 2004, Havens shut down. “We had just taken over a $350-million GMP and a major component collapsed under us,” says Muldoon.
AMEC cobbled together a deal with Interstate and fabricators W&W and Owens Steel. It also covered an $8.3-million steel price surcharge, which nearly swallowed its entire contingency fund. The CM also guaranteed contracts with the mills, the connection engineer and the detailer. “Interstate did not have the wherewithal,” says Muldoon.
On top of that, soon after construction started in April 2004, work stopped for eight months to remove contaminated material from the site. Then, in May 2004, AMEC’s parent company, AMEC plc, London, announced it was giving up on its U.S. buildings business (ENR 6/14/04 p. 11). The Times project would be Muldoon’s last hurrah with AMEC. And it would be the final curtain for the remnants of former construction giant Morse Diesel International, which AMEC had bought in the mid-1990s.
The news was bittersweet for Muldoon, who joined Morse Diesel in 1977, left during the 1980s and returned in 1990. And it was another blow for the Times job because “everyone started running for the door,” says Muldoon.
AMEC offered incentives to keep the 18-person Times team intact. Most stayed because “the job was a good resumé builder,” says Muldoon. But the corporate security blanket was gone.
The owner wasn’t happy, either. “They should have been more forthcoming with us from the beginning, though in the end, it worked out,” says Bob Sanna, FCR’s executive vice president for design development and construction.
Muldoon’s attention was soon diverted. In December 2004, AMEC pulled the plug on Interstate, claiming it wasn’t performing. Ultimately, Interstate went bankrupt and AMEC paid $750,000 to retrieve steel it says it had already bought.
To keep things going, it signed DCM Erectors Inc., New York City, to fabricate the remaining 5,000 tons of the 22,000 tons of steel, rework another 2,000 tons and erect the frame. Steel erection started in May 2005 and was substantially complete, on schedule, by July 21, 2006.
Exposed-steel erection was complicated by welding, grinding and X-rod stressing.
That was no small feat and was complicated by inherited decisions. At one point, DCM had 10 plants fabricating steel. A big drag was the extensive field welding. “We pleaded for less welding, but it was too late” to switch gears, says DCM President Larry W. Davis. He says he’d never seen so much welding in 30 years.
Davis won’t reveal DCM’s contract price, but says he is still waiting for payment for extras.
The skyscraper, which has a four-story extension, is currently 95% complete. “The way it looks now, we’re going to squeak by,” says Muldoon.
The 190 x 145-ft tower is 745 ft tall to the roof. A giant steel fence makes the tower 784 ft, and a mast tops out at 1,046 ft. Each of the tower’s corners has a 45x20-ft notch, forming a fat cruciform footprint. Each notch is framed using exposed columns and beams, with two-story X-bracing.
Even with the luxury of time, Piano’s vision of transparency was not easy for the design team to realize. For the structural engineer, the biggest challenges were developing an efficient structural system within the architectural constraints, developing external connections that were aesthetically acceptable and practical to build and designing for thermal movements that result from the use of weather-exposed steel. “If we wanted elements to change in a controlled way, we had to control the depth of the column, the thickness of the exposed flange and the return dimension,” says Scarangello.
Such finesse is uncommon to structural design, he adds. For example, box column corner-to-corner dimensions remain constant at 30 in., while exposed flange thickness steps from 4 in. at the tower base to 2 in. at the top. The web inset dimension is always 3 in., but web thickness varies depending on strength requirements, from 8 in. at the base to 1 in. at the top. And the change is hidden, says the engineer.
Each notch has two exposed column lines, with beams and prestressed X-braces made of steel rods. To satisfy the architecture, even the exposed X-rods and beams decrease in size in a controlled way, over four vertical zones, as they rise.
|Intumescent paint in notches required enclosures (above) that trailed steel.|
Exposed columns and beams are fireproofed with intumescent paint. The X-rods could not be easily painted, so they could not be part of the lateral system, says the engineer. Core bracing supports the building for strength under lateral loads, while the rods help with serviceability requirements for lateral drift and acceleration. To minimize differential thermal changes in length between exposed columns and perimeter columns, the engineer devised a “thermal” belt truss at the 51st floor. It ties together the four exposed columns not engaged by two levels of outriggers, midheight and at the top. The belt truss also adds to the efficiency of the lateral-load-resisting system and offers redundant load paths in the event of an extreme event. (The Times says that after 9/11, it put $4 million more into the structure to harden it.)
On the exposed structure, workers had to meet tight tolerances and grind all surface splices, both for esthetics and for the intumescent paint. X-rod turnbuckles needed hydraulic jacking. “It was complicated,” says Davis.
But welding was the big challenge. “We had three generators with a...