http://dcnonl.com/article/id32992
More than a job, World Trade Center is a point of pride
Double shifts, seven days a week for Collavino crew in New York
50,000 cubic yards of concrete was slated to be poured just to get the Freedom Tower job up to street level.
IAN HARVEY
March 12, 2009
Renzo Collavino is far from home, deep in a 16-acre hole at what was and what will be one of New York’s most famous landmarks.
Work at the World Trade Center Freedom Tower is progressing slowly; too slowly, in fact, dragged back by a series of issues around how to best preserve existing structures and the subterranean rail lines below the massive hole excavated after the towers were downed in the infamous 911 attacks.
“The project is several months behind schedule,” says Collavino, who with brother Paolo and father Mario, make up Collavino Construction Group, the Windsor-based outfit which is the main sub-contractor on the US$300 million-plus concrete job.
Add in the credit crisis and the sudden evaporation of money needed to keep construction projects like the WTC rolling and it’s been a rough few months. Renzo and his key managers live in New York and commute home to Ontario every two weeks.
Despite the chaos and the pressure of the ever-ticking clock, his voice is calm and contained. These are delays outside of his realm of control.
His focus remains on the below grade portions of the works with special attention on the elevator shafts and ensuring there’s no thermal cracking.
“We’re on double shifts seven days a week now so we are doing our part to be back on schedule by summer,” he says.
The US$3 billion Freedom Tower will have an illuminated spire and top out at 1,776 feet — an auspicious number marking the birth of the American republic.
It will feature an observation deck at 1,300 feet with a square glass parapet paying homage to the original Twin Towers.
The tower rises from a cubic foundation and tapers into triangles while forming an octagon at its centre. Over the 105 floors will be 2.6 million square feet of space which are slated to open in 2013.
The concreting operations are still below grade, with about 50,000 cubic yards total pour slated to get the job to street level.
Then, the structural steel will commence followed by pouring of concrete on metal decks, concrete elevator core walls and auxiliary works such as walkways, slabs, stairs, pads and curbs.
It sounds easy enough but the logistics are a nightmare. The lower Manhattan site is smack dab in the middle of an old historic area with narrow streets and limited access.
Materials can only move by schedule, early in the morning or at night and nothing can sit on the street waiting for a delivery window for more than 30 minutes.
Still, getting a workforce hasn’t been an issue as it might be on other jobs.
“Everyone wants to work on this, to make a contribution,” he says. “There’s a lot of pride surrounding the construction of this tower.”
Indeed, for many of the trades, their fathers, uncles and cousins worked on the original structures and creating a new structure has become a mission and a statement.
The job is also a challenge, technically.
“We’re dealing with 16,000 psi concrete on the elevator shafts where there’s a 160F temperature requirement and the maximum allowable variation from the inner and outer walls is 30F,” he says.
“So we’re using ice during the initial curing process in both summer and winter to control the temperature.”
The elevator shaft walls vary from two to six feet and have considerable amount of reinforcing steel, he says.
“I’ve never seen anything like it,” he says.
The design has been predicated on the events that transpired on Sept 11, 2001, to ensure that the building will never suffer the same tragic fate as its predecessor, the Twin Towers.
The original World Trade Center tower collapsed quickly when the heat from burning jet fuel weakened the steel structural components, leading to failure and a domino effect which brought the floors crashing down on each other. This time, designers and engineers are trying to ensure it will never happen again.
All the rebar is also bent and laid by hand, he says, since local union rules prevent use of pre-bent rebar delivered to site.
The project is presently approaching grade with the expected completion to mid to late summer.
“In the next coming months we will be focusing our attention on organizing and planning the above grade works which will include a 4 foot thick, 70 ft high blast wall around the perimeter of the base of the tower. Collavino states.
“Though this project has its daily challenges, we continue to move forward towards the completion of the tower, a symbol of freedom and a testament that America still stand strong.”
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