Progress

By Debra Wood

Although controversy once again swirls around redevelopment of the World Trade Center site in Lower Manhattan, both the Port Authority of New York and New Jersey and Silverstein Properties of New York report their projects are on schedule and progressing well.

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“The public side of the World Trade Center site is clearly moving forward,” says Port Authority Executive Director Chris Ward in an e-mail. “Last year’s assessment was an important turning point, but much more work lies ahead. We must continue pushing aggressively until every project is complete.”

Port Authority spokesman Steve Coleman says in another e-mail that One World Trade Center, the National September 11 Memorial and Museum, and the Transportation Hub are on schedule. Current target dates, according to the Lower Manhattan Construction Command Center, which had no one available to comment about progress at the site, are 2013 for Tower One; Sept. 11, 2011, for the memorial plaza and mid-2013 for the rest of the memorial; and mid-2014 for the transportation hub.

New York Construction reported in 2006 that the original completion dates were 2011 for Tower One; Sept. 11, 2009, for the memorial; and the end of 2009 for the transportation hub.

Candace McAdams, another Port Authority spokesperson, says the Port Authority reassessed the construction program last year and put together new timelines and a new budget in October. The projects are meeting those new schedules, McAdams says. Nearly 1,000 people are working onsite at the Port Authority’s three projects. In mid-June, the Port Authority completed the sale of $750 million in consolidated bonds allocated for capital expenditures in connection with One World Trade Center, the retail components of the World Trade Center site and other World Trade Center sitewide infrastructure.

During an eventful year on the World Trade Center site, crews found glacial formation at the site of Tower Four during excavation. (Photo by Joe Woolhead)

On the private side, Scott Thompson, project manager for Silverstein, says Tishman Construction Corp. of New York is making good progress at World Trade Center Tower Four, also known as 150 Greenwich St., for World Trade Properties, an affiliate of Silverstein Properties of New York.

The Port Authority, however, remains in a standoff with developer Silverstein Properties over the developer’s request for the Port Authority to guarantee as much as $3.2 billion in construction loans. In early July, Silverstein Properties provided the Port Authority with a “Notice of Dispute” letter, reflecting the Port Authority’s inability to meet its rebuilding obligations at the World Trade Center and the major financial and logistical consequences of these failures on the Silverstein organization’s ability to rebuild.

In a written statement, Silverstein Properties says the notice triggers a 10 business-day period for the parties to meet to try to resolve their differences. If they fail to achieve an agreement, either party can ask to resolve the dispute through binding arbitration.

“Today’s action is designed to inject a renewed sense of urgency to these discussions and, should those discussions fail, to take the matter to an impartial panel of experts as early as this month,” says developer Larry A. Silverstein in the written statement. “One way or another, we must take any and all steps necessary to resolve, once and for all, the disputes that have arisen as a result of the Port Authority’s continued and admitted delays.”

The Port Authority issued a written statement in response, from Ward,saying, “It’s unfortunate SPI is walking away from the negotiating table simply because the public has been unwilling to sacrifice critical transportation projects to subsidize private speculative office space. The Port Authority is meeting all of its obligations, and we look forward to a quick arbitration decision should Mr. Silverstein continue down this legal path.”

World Trade Center Tower Four Tishman broke ground on the $2-billion, 64-story Tower Four, designed by Maki and Associates of Japan, in February 2008. It will contain three levels of retail space and about 2.3 million sq ft of office space. The Port Authority has agreed to lease a third of it.

During excavation, crews found a glacial fill, with smooth rocks and boulders that required removal and filling with a flowable-fill concrete.

“It’s a lightweight concrete that will find every crevice,” Thompson says.

Crews completed foundation work, columns and slab-on-grade, on the first phase in January and on the second phase in June. Phase two was delayed because the Port Authority did not turn over the site to Silverstein until March, rather than June 2008. Thomspon says the turnover was delayed because a wall installed by the Port Authority to replace the secant wall ran through Tower Four’s foundation, which its columns sit on.

Crews place reinforcing steel at Tower Four, which will also be known as 150 Greenwich St. (Photo courtesy of Silverstein Properties)

“We changed the construction method of the superstructure,” Thompson says. “Normally, you would build floor by floor as you came up through the four basement levels, but we ended up going to a wedding-cake [method]. They would build a section of each floor and tier it up instead of going from slab to slab.”

Thompson credits the concrete subcontractor, Rogers & Sons Concrete of Lagrangeville, N.Y., with coming up with a good strategy to keep the project moving forward. In June, approximately 180 people were working onsite, 160 of them employees of Rogers.

The tower has high-strength concrete core walls, a structural-steel frame and concrete slabs. Upper floors will have a metal deck. The team used a 12,000-psi concrete for the core walls and 6,000-psi concrete for the slabs. Structural engineer Leslie E. Robertson Associates of New York modeled the concrete and steel. DCM Erectors of New York and Rogers used the three-dimensional model.

Mechanical, electrical and othertrades were working below grade as the building began rising above street level.

Crews on Tower Four completed foundation work, columns and slab on grade, on the first phase in January 2009 and on the second phase in June. (Photo courtesy of Silverstein Properties)

“As we proceed up the building, all the mechanical trades follow,” Thompson says. “We’ve coordinated MEP through the 23rd floor, which is significant, because you can start fabricating all of the pipe and ductwork and release equipment.”

As with the other planned towers, the team aims for LEED gold certification.

Completion is scheduled for late 2012 or early 2013.

The Port Authority has not released the Tower Two and Tower Three sites to Silverstein. The Port Authority must complete the excavation to approximately 80 ft below street level, says Dara McQuillan, Silverstein vice presdient.

Steve Coleman, spokesman for the Port Authority, responded by e-mail, “We are working with SPI on a final turnover agreement to facilitate the transfer of the other sites to them.”

One World Trade Center Tishman also is managing construction on the $3.1-billion, 2.6 million-sq-ft, 102-story One World Trade Center, formerly known as the Freedom Tower, for the Port Authority, which will own and manage the building. Construction began in April 2006 on the steel-frame tower designed by Skidmore, Owings & Merrill of New York.

By mid-summer, the superstructure at the $3.1 billion One World Trade Center was 105 ft above grade, using 2,315 tons of structural steel and 33,000 cu yd of concrete. (Photo by Michael Falco)

By late June, the superstructure had risen 105 ft above grade. DCM had erected 2,315 tons of steel. Collavino Construction Corp. of New York had placed more than 33,000 cu yd of concrete.

The team is using 14,000-psi iCrete, a precisely blended mix of aggregates and cement, for the shear walls, some of which are up to 6 ft, 6-in. thick. Thirteen shear walls have been poured as of July, with the psi reaching 17,000 on several occasions. Maximum concrete temperatures must stay below 160 degrees F, with maximum differential temperatures between the wall center and face maintained within 35 degrees F. The mix employs fly ash and slag, using only 300 lbs of cement per cu yd instead of more than 1,000 lbs of a comparable mix.“Workers are erecting steel and pouring concrete on a daily basis, placing some of the largest steel members ever fabricated and completing some of the largest continuous pours on record,” Tishman says in a written statement.

Steel erection on the National September 11 Memorial and Museum was about 65 % complete this summer. The centerpiece of the memorial will be a plaza at the footprints of the original twin towers. (Photo by Michael Falco)

The Port Authority has secured the first private tenant for One World Trade Center –Vantone Industrial Co. It joinsprospective state and federal government tenants and brings the building to 50% occupancy.

Sept. 11 Memorial Bovis Lend Lease of New York continues construction on the National September 11 Memorial and Museum. The memorial consists of a plaza with two voids filled with water at the sites of the twin towers’ footprints and a museum adjacent to the pools. Steel erection was 65% complete in June, about 20,000 cu yds of concrete had been poured and the north pool had been formed and the south pool was under way. Bovis declined to comment.

WTC Transportation Hub The $2.2 billion World Trade Center Transportation Hub, designed by Spanish architect Santiago Calatrava, will include a PATH station and connect to 14 subway lines via the Fulton Street Transit Center and other terminals. It will link pedestrians to the World Financial Center through an underground concourse.

Phoenix Constructors, a joint venture among Fluor Enterprises of Irving, Texas; Skanska USA Civil Northeast of Whitestone, N.Y.; Bovis Lend Lease; and Granite Construction of Tarrytown, N.Y., began work on the hub in September 2005 for the Port Authority.

Excavation is ongoing at the site of the former temporary PATH station and beneath the No. 1 subway box. In addition, crews installed 47 structural arches to form the East-West Connector.

The Port Authority awarded a $338.8-million contract earlier this year to DCM Erectors to furnish, fabricate and erect 22,305 tons of structural steel for the Transportation Hub, which will bring the hub to grade. It includes the Transit Hall, permanent underpinnings of the No. 1 subway and Greenwich Street, and pedestrian connections to other parts of the World Trade Center. This steel will form part of the floor for the 9/11 Memorial Plaza.

Phoenix Constructors did not respond to requests for more information.

Useful Sources:

World Trade Center (Port Authority): http://www.panynj.gov/wtcprogress/index.html
World Trade Center (Silverstein Properties): http://www.wtc.com/about/
Lower Manhattan Construction Command Center: http://www.lowermanhattan.info