By Michael Franco
In the wake of the wreckage that occurred on Sept. 11, 2001, there's been much talk of reconstruction — both emotional and physical. Now, solid, visual evidence of that reconstruction is beginning to rise like a phoenix from Ground Zero at New York City's southern tip. When completed, One World Trade Center (One WTC) will stand as North America's tallest building — a glass and steel symbol of resiliency, as well as scientific and architectural triumph.
One World Trade Center faced a few challenges along the way. Not only did the $3.1 billion-dollar structure need to be attractive, it had to be the most secure office building ever constructed. In addition, because One World Trade Center is part of the larger reconstruction effort taking place on the grounds of the former Twin Towers, the coordination with other onsite projects presented a logistics nightmare — especially since commuter trains run through the center of the construction at ground zero day and night.
The plans for Ground Zero are finalized, and from them a skyscraper is emerging that will dazzle the eyes and perhaps knock your socks off. Take a tour of One WTC with us and check out some of the coolest features from one of the most-watched construction projects in history.
5. The Bomb-proof Base
Beauty and security — One World Trade Centerdemanded both. The solution was elegantly simple: create a bunkerlike base that could withstand the force of a 1,500-pound (680-kilogram) truck bomb and cover it in prismatic glass that would please the eye and disguise the superstrong blast walls.
This fhttps://www.dnitv.net/fs-tool/content/EditArticle.actionortress foundation stretches 20 stories high and is known as the podium — the base from which the rest of the tower will rise. At 40,000 square feet (3,716 square meters), itâ€™s the same size as the footprint of the original Twin Towers.
The podium owes its strength to a type of concrete known as iCrete, which can withstand a stunning 14,000 pounds-per-square-inch (psi) of pressure — the highest ever poured in New York, according to Lynda Tollner, program director in the World Trade Center Construction Department. Comparatively, normal sidewalk concrete can stand up to 3,000 psi while the concrete used in a typical high-rise won't flinch at 5,000 psi. Did we mention that this special concrete only has 90 minutes to arrive on-site after it has been mixed in Brooklyn?
4. Strong, Speedy and Selective Elevators
In addition to forming the virtually impenetrable podium of One World Trade Center, iCrete also will reinforce the elevator shafts running through the center of the building like spinal columns. The concrete surrounding the shafts is 3 feet (1 meter) thick in some areas and so dense that jackhammers simply bounce off it. By switching the emphasis to the inside of the building, instead of leaving it up to the steel frame to support the structure (as with most skyscrapers), engineers believe One World Trade Center will be sturdier and more collapse-resistant. That said, the skyscraper will still feature 25 tons of steel girders, which will form the building's perimeter.
The elevators themselves will be the fastest in North and South America, according to the ThyssenKrupp Elevator Corporation, the company responsible for manufacturing and installing them.
A total of 71 elevators will operate in the building's core, zipping tourists and employees up and down at the speed of 2,000 feet (610 meters) per minute, the company says. But you won't be able to simply enter these speed shuttles and push a button for your floor — there won't be any. Instead, a unique recognition system will identify each passenger and deliver them only to the floor for which they are authorized.
3. The Safety Specs
The stairwells (which will be pressurized with their own air supply) will get their share of formidable concrete, too, along with all of the building's safety systems, including exhaust and ventilation shafts, electrical and plumbing columns, and communication antennae. Even the building's sprinklers will be shielded by concrete guards.
And what if disaster occurs? The building's state-of-the-art communications cables will alert the authorities, and occupants will move to tenant collection points on each floor and await firefighters, who will be able to reach them via a dedicated emergency-services stairwell. In the event of such an occurrence, the air quality is expected to remain high thanks to biological and chemical filters in the ventilation systems. Emergency lighting systems will have multiple back-ups, enabling the building itself to work its hardest to ensure the safety of its tenants.
2. The Glass Gown Outside
Let's head outside to catch a glimpse of the glass that will wrap around One World Trade Center like some sort of dazzling dress made of Teflon.
The special glass will be highly blast resistant, which only adds to the tower's strength. The ultra-low-iron glass known as "extra-white" should still keep things attractive though. It has less green in it than other types and allows exceptional light transmission to the interior spaces — a feature that will help cut down on lighting bills.
Panes of this gorgeous glass will be attached to the building's frame without the use of mullions — the dividers you often see between panes of glass in skyscrapers — allowing the structure to keep its smooth figure.
Adding an extra dash of dazzle to the north and south entrances will be a type of glass known as dichroic, which is often used in vividly colored glass jewelry. Its unique nature allows certain wavelengths of light through while reflecting others, creating beautiful prismatic effects.
1. The Antenna
Crowning One World Trade Center and bringing the building to the symbolic height of 1,776 feet (541 meters) will be a broadcasting antenna measuring 408 feet (124 meters). Encased in a radome, a unique protective enclosure that's transparent to radio waves, the antenna will also be guarded by a decorative steel spire. A latticelike ring will sit at its base and serve as a docking station for other broadcasting devices such as point-to-point microwave dishes and electronic news-gathering antennae. The ring will further protect the mast thanks to eight translucent Kevlar cables that will stretch from the ring to the antenna, to steady it in high winds. And of course, the city of New York will want to keep its new masterpiece clean, so window-washing equipment will also be built into the ring.
Finally, the slowly rotating beacon at the top of the antenna will flash out Morse code for the letter "N" which stands for New York. New indeed.