The headlines about the redevelopment of the World Trade Center site usually include “arbitration,” “notice of dispute,” and “finally started” — with only the occasional mention of any good news. For the people involved with the construction of all the towers and public spaces at the 16-acre site, many of whom have been at it for close to a decade now, this can be particularly frustrating. Because they have been working, regardless of the squabbling between the 19 stakeholders — Silverstein Properties, Port Authority of New York and New Jersey, ConEd, Verizon, and a host of notoriously slow city agencies that each have a say, and indeed a vested interest, in how the final version of the site will look and function.

“When people say there wasn’t a lot of momentum, it just wasn’t visible,” says Mel Ruffini, project executive for Tishman Construction, which is managing work on the towers 1, 3 and 4 at the World Trade Center Site. Ruffini has been working on the site since 2002, starting with 7 World Trade Center and has since worked on each of the other rising towers. “People don’t realize how large the work is below grade.”

Overall, the site stretches 3 million sq ft underground — including the below-grade retail center, the Santiago Calatrava-designed Transit Hub, the connecting corridors leading to the 13 subways stations and the World Financial Center, a Vehicular Security Center, parking, and the World Trade Center Memorial.

“It’s very time consuming, slow, tedious work that took a significant amount of time.”

The Towers

The World Trade Center’s towers will add more than 10 million sq ft of office space to downtown Manhattan, more than the 8.8 million sq ft available in the original Twin Towers. Unsurprisingly, filling that much space, in this economy, remains an issue for everyone involved, namely the site’s developer Silverstein Properties and its owner, the Port Authority of New York and New Jersey. 7 World Trade Center, the first Silverstein property to go up on the site and completed long before the recession in 2006, has leased about 86% of its 1.7 million sq ft, according to Silverstein — although it already stood at two-thirds leased as far back as 2007.

As a result of the slow market for office space, Tower 2 is temporarily on hold, although the plan is to bring it to street level to await future development. Tower 5, a PANYNJ project, is still in the planning phase.

Towers 1, 3, and 4, however, are very much underway.

If there is an inspiration for the towers, it is probably the Time Warner Center in Manhattan’s Columbus Circle. In fact, the project managers on Towers 3 and 4 worked together on that project. As a result, a key feature of the entire site is substantial retail space in each of the buildings; glass-enclosed, two- to three-story lobbies; open floor plans with a minimum use of columns to maximize tenant space; smart elevators and separate entrances for retail and offices. In addition, despite outward differences — the architects on the towers have decidedly distinct aesthetics, spanning three continents — each of the towers shares a rigorous approach to safety, with setbacks from the street and a heavily reinforced concrete core housing all life systems and escape routes and a steel superstructure, exceeding the levels set both by the city’s building code and PANYNJ.

This approach was first used in 7 World Trade Center and is anticipated to define the future of high rise construction in New York. And of course, to compete with the real estate uptown, each building will incorporate green and energy-saving technologies—another standard set by 7 World Trade Center, which was the first certified green office tower in the city, receiving LEED Gold certification.

Tower 1

Tower 1, the flagship building, will soar 102 stories to a symbolic height of 1,776 ft when completed at the end of 2013. It will include 2.6 million sq ft of office and retail space, two television broadcast floors at 1,120 ft, two restaurants and an observation deck, above which a metal-and-glass parapet will mark the heights of the original towers, at 1,362 and 1,368 ft. A 408-ft antenna will sit atop the roof inside an illuminated mast meant to evoke the torch on the Statue of Liberty.

The tower was designed by David Childs of Skidmore, Owings & Merrill — appropriately, a New Jersey native among a spectrum of foreigners on the WTC site. In its initial plans, the building was known, and is still referred to by many New Yorkers, as the Freedom Tower. The name, according to a real estate source, was dropped because as an office tower the connotations would drive away leases, without which the tower would never be constructed.

Foundation work started in early 2006, but the $2.9 billion project changed hands that fall as Silverstein stepped down and PANYNJ took over. Much of the work, as is the case with every project on the WTC site, has taken place over the past four years below grade. Tower 1 will have 500,000 sq ft of space under ground, as well as connections to the 13 subway lines, PATH trains, the World Financial Center, and possible future trains to the airports (most sources interviewed for this article were very cautious about anything not already under construction).

Some innovations include using internal cranes set on forms that will rise with the core, as well as safety netting covering the top 18 floors of the building being worked on. But now that the tower is under way, with steel erection already above the 30th floor, the work is relatively straightforward. The safety and security features, however, are anything but.

The building will have biological and chemical filters in the air systems, extra-wide stairs, interconnected exits, with egresses going out on every street surround the building (New York skyscrapers’ fire stairs typically come out in the lobby), backups on lighting, concrete shelters for sprinklers and risers, a dedicated stairwell for firefighters, and extensive fireproofing. At the internal core, which will contain the egress stairs, air shafts, standpipes and elevators, the concrete is on average 3 ft thick and goes up to 6 ft 6 in. To achieve that level of security on a 102-story tower will require 48,000 tons of structural steel, 47,000 tons of rebar, and 215,000 cu yards of concrete. When it’s clad, the exterior will have around 1 million sq ft of curtain wall. The site has two tower cranes and a sliding crane. But to get everything done on a site with unprecedented levels of security is what really makes up for the complexity.

“We have an advantage, we’re not interfacing with other projects,” Ruffini says. “But we’re pushing 800 workers, 40, 60, 70 trucks, and that’s going to increase in the next year or so. Everything has to be monitored very carefully primarily because of security reasons. A truck can’t just show up, they won’t be allowed.”

Although at the time this publication was going to print the PANYNJ was still involved in negotiations with developer Douglas Durst to come in as a partner to help manage the leasing, the physical construction is proceeding on schedule and is slated for completion in the end of 2013. The crew will double from 800, according to Ruffini, and to keep up with the schedule the team works in two shifts, some weeks seven days a week, with trucks coming in from 3 am to 9 pm.

Tower 3

Sean Johnson, vice president of Silverstein Properties, came on to oversee Tower 3 in May 2007.

“I was on the development team [at Time Warner Center], and they asked if I wanted to do something as or more complicated,” he says. “I’m a glutton for punishment, what can I say.”

Designed by British architect Richard Rogers, Tower 3, at 175 Greenwich, will rise 71 stories to 1,140 ft, and will include 2.5 million sq ft of office space. It houses five trading floors 65,300 ft wide and served by eight dedicated elevators. In addition, five retail floors, with two below grade, will sit at the building’s base. As with 7 WTC and Tower 1, Tower 3 will have a central reinforced concrete core and identical safety measures, and is already projected to meet LEED Gold standards. Rogers’ design also includes exterior bracing on the setbacks and most of the exterior of the curtain wall, complicating the work on the tower itself, but, like its neighbor at 150 Greenwich, Tower 3 has various stakeholders underneath its base and is coordinating sleeves and inserts in the thick concrete to keep up with the construction schedule.