One World Trade Center: Rebuilding From the Ashes

There is no doubt that the attacks that occurred throughout the United States on September 11, 2001 (twelve years today) changed the course of history. The Twin Towers, located in New York City, collapsed two hours after the first plane hit the north tower. The death toll for these attacks totalled over 3000 (History Channel).

To pay tribute to the victims, plans were made to construct a memorial complex on the site of the old Trade Centers. This complex features five new skyscrappers, a 9/11 memorial and museum, a World Trade Center transportation hub, retail space, and a performing arts centre (World Trade Center). The extensive plans have involved some of the most famous architects, artists and urban developers of our time, including: Santiago Calatrava, David Cholds, Norman Foster, Frank Gehry, Daniel Libeskind, Fumihiko Maki and Richard Rogers (World Trade Center).

The memorial features two 16-acre reflecting pools which are set in the original footprints of the two towers. The largest man-made waterfalls in North America are located in the centre of these pools, and the names of the victims are written around the pool’s edges.

Photo of the World Trade Center Memorial Taken During My Recent Visit to New York

For Every Action, There is an Equal Larger and Opposite Reaction

In addition to the memorial, plans were made to build five new skyscrapers. One World Trade Center, sometimes incorrectly referred to as Freedom Tower (Wall Street Journal), will be the tallest building in the western hemisphere, and the fourth tallest building in the world upon completion. The roof top has a height of 1368 ft (417m), identical to the height of the original North Tower. However, the steel spire situated at the top of the building bring the total height to 1776 ft (541 m). This acts as a symbolic reference to the date that the United States signed the Declaration of Independence, separating the colony from the British Empire.

The structure is composed of a concrete core surrounded by a steel structure. As a result, the tower acts like a ‘building within a building’, attaining a level of safety which far surpasses the current requirements in building codes. Steve Plate, the director of World Trade Center construction for the Port Authority of New York and New Jersey, stated, “The core walls aren’t sheetrock like the original towers, they’re more than 6 feet of concrete in places. We’re rewriting the book on security for office towers.” In addition to this, the podium at the base of the building consist of a 187 ft tall by 200 ft wide concrete slab, increasing the towers safety. (Popular Mechanics).

Once completed, this building will play host to 69 office floors, two television broadcasting floors, two restaurants, an observation deck, and a glass-metal parapet (World Trade Center). The construction of the tower, which began in 2006, is expected to be completed in early 2014.

Current Progress of Freedom Tower Construction. Taken on my Recent Visit to New York City.
Current Progress of On World Trade Center Construction, Taken on my Recent Visit to New York City.

Green Reaches New Heights

One of the most important features of the new landmark is the achievement of a LEED Gold certification. This has been attained through the use of various green technologies. The 57th floor will play host to two 25,000 gallon (94,600 L) rainwater collection tanks, which will be used for the buildings operational needs. In addition, the toilets are shaped in a way to increase the velocity of the water flushing, reducing the amount of water per flush.  According to Steven Plate, It not just helps the environment. It also saves a lot of operational costs.” (MSNBC News)

Some other ‘green’ features include: the use of recycled debris and materials during construction, an increase in the use of natural light, and an LED backlight system for the podium which is both cost-effective and creates less heat energy,

However, the ‘green’ emphasis has lead to construction costs of almost $4 billion (US), making it the most expensive office tower ever built (Wall Street Journal). Despite this, the significantly lowered operating costs and energy usage make the project economical from a life cycle perspective. For more information about the LEED program, see my previous post entitled “LEED-ing the Way to a Better Future“.


Before the final steel beam was lifted into place for One World Trade Center, President Barrack Obama inscribed, “We remember. We Rebuild. We come back stronger.” (Telegraph) The symbolism behind this is quite strong, and personify’s the project as more than just a building; it represents the resiliency of the American people, and acts as a tribute to those that lost their lives in the horrific attacks.

It is important that people do not forget the past. History can teach us important lessons about the future, and can be one of the most important tools in making the world a better place. This tower stands as a testament, not only to those who lost their lives, but to the thousands of men and women who have worked on building from the ashes. The lessons learned from the collapsed towers are studied all across the globe, and have helped develop new techniques for creating stronger, more resilient structures. It is believed that this will create a new standard for high rise construction, ensuring that the events of September 11 will never again occur.

To see additional construction photos, visit the Structural Digest Gallery.

LEED-ing the Way To a Better Future

In the past few decades, the terms ‘green’, ‘eco-friendly’ and ‘sustainable’ have emerged as buzz words used to market new products and ideas. Their grasp has not evaded the building industry, as more and more projects are now using ‘sustainable’ construction practices. However, in order to build sustainably, one must be able to define it. In 1987, the United Nations defined sustainability as, “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (United Nations)

In 1998, the U.S. Green Building Council (USGBC) developed the Leadership in Energy and Environmental Design (LEED) program to act as a third party recognition for green buildings. By using a pre-set rating system, buildings can earn points which allow for different levels of certification (Certified, Silver, Gold and Platinum). It has been proven that the use of the LEED system can lead to lower operating costs, increased asset value, reduction in energy/resource use, and healthier/safer environment for occupants (USGBC). In addition, meeting LEED standards allows buildings to apply for money-savings incentives and tax rebates.

In the United States alone, USGBC estimates that more than 4.3 million people live and work in LEED certified buildings. It is also estimated that 44% of all commercial and institutional construction in America is “green”, the majority of these associated with the LEED program. USGBC estimates that this percentage will surpass 55% as early as 2016 (USGBC Report).

International Implementation

Due to it’s success, the LEED certification program is now being implemented throughout the world. Taipei 101, located in Taiwan, is one of the tallest buildings in the world and boasts a LEED Platinum certification.

One of the key features of Taipei 101’s environmentally friendly setup is a 30% decrease in potable water usage (compared to average building consumption), saving about 28,000,000 litres of potable water annually (USGBC Taipei 101 Summary).

Canada’s Response

In 2002, Canada developed the Canadian Green Building Council (CaGBC). The CaGBC acts similarly to the USGBC, providing resources to projects aiming for LEED certification, as well as training LEED accredited professionals.

This has lead to an increasing number of LEED certified buildings throughout the country. A building located in Waterloo Ontario was one of the first student residences to achieve LEED Platinum accreditation. Despite costing the developer 10% more to build than traditional construction, this building boats low energy consumption and very low maintenance costs (The Record). In addition, the Waterloo region has a number of other developments looking to achieve similar LEED credentials. This is a promising sign for Canada’s version of ‘Silicon Valley’.

In Vancouver, a construction permit has been submitted for what will be one of Canada’s tallest office towers with LEED Platinum certification. Construction of the $200 million building will begin in October, and is expected to be completed in 2017 (CBC Report).

Proposed ‘Green’ Offic Tower in Vancouver. Photo Credit: Buzz Buzz Home

The new tower will use half the energy of traditional office buildings that are similar in size, greatly reducing the operating costs for tenants. This marks the beginning of what many hope will be the ‘green revolution’ in Vancouver. Herbert Meier, director of real estate asset management for the project stated, “We believe in Vancouver’s economy and its future…We believe in supporting the City of Vancouver’s vision to become the world’s ‘greenest’ city by 2020.” (CBC Report)

It is apparent that the current standards for construction are inadequate. As a result, the industry must continue to embrace the ‘green’ movement by implementing new techniques. It is encouraging however that as the industry begins to incorporate the principles set forth by LEED, cities will begin to finally take action on the growing issue of climate change.

Modular Structures: A Lesson from LEGO

With the recent advent of modular construction, a number of new and interesting projects are popping up all around the world.

Gluck+, an architectural firm based out of New York City, has designed a medium-income, seven storey, 28 unit apartment building in Upper Manhattan. The buildings lot size posed a serious concern for builders, as it does not provide the area required for traditional construction projects. Therefore, the architects at Gluck+ chose to assemble the residence using 56 pre-fabricated modules, all of which are built in a factory in Berwick, Pennsylvania (Architectural Record).

Proposed Modular Building in Upper Manhattan. Photo Credit: Gluck+

Building the modules in a factory allowed for high levels of quality control, and provided a much more comfortable building environment for workers. In addition, the project could proceed notwithstanding weather conditions. This has lead to an estimated 15% savings in total project cost. The construction time has also been drastically reduced, and the project will take just under one year to complete (four modular units are installed per day, after the initial foundation has been constructed). The residence, which is expected to be completed in October, is also quite aesthetically pleasing. By pulling some stacks forward and pushing others back, several terraces and overhangs are created, giving the structure a distinct look. The assembly process for the modules is presented in the following video:

A number of other modular residential buildings have been popping up in New York. A 32 storey residential housing unit in the Atlantic Yards development site is under construction. When completed, the building will be a whopping 322 ft tall and will hold the title of tallest modular building in New York. Skanska, the company building this project, has estimated that the total cost of the modular building will be 20% less than a traditional building (Skanska News Report). Similar to Gluck+’s design, 60% of the construction will occur off site. The modules will be built in a controlled environment in Brooklyn’s Navy Yard, and will be transported to site. As a result, the building is expected to attain LEED Silver certification, and produce 70 to 90% less construction waste (than traditional construction).

Final Render of the Tallest Modular Residential Building in New York. Photo Credit: Skanska

However, there are often risks when implementing new technologies. The Plumbing Foundation of New York City is suing the Department of Buildings for ignoring a number of major building safety rules. Stewart O’Brien, the executive director of the Plumbing Foundation stated, “It’s a dangerous path we walk down when the city appears to be willing to circumvent the clear words of the law so that wealthy and influential developers can make a few extra dollars by using lower paid and untrained assembly line workers” (The Real Deal).

Despite the issues that builders face with this new technology, it is apparent that modular buildings are becoming very popular with engineers and designers. Projects like this, as well as Sky City in China, are indicators of the shift in construction practices within the industry.

It seems quite ironic that the construction industry, which has a history of using immensely creative and complex building techniques, is now reverting quite successfully to the intuitive building style of LEGO.

The Future of High Rise Construction

In the new age of technology, the concept of “slow and steady wins the race” is becoming less and less applicable. In particular, China has recently constructed a series of buildings using pre-fabricated modular sections, cutting the time spent on the construction site to a matter of days.

The world was shocked when they first saw this phenomenon performed in Changasha China, where a thirty storey building was constructed in just fifteen days. If you have yet to see it, here is the amazing time-lapsed footage of the construction process:

The foundation for the structure was already installed prior to the thirty day count, reducing the overall “construction time”. In addition, the project used pre-fabricated modules that were constructed in a manufacturing plant and later shipped to the construction site. Once the pieces were on site, it was just a matter of putting the pieces in place (similar to a standard LEGO set).

The company behind all this, Broad Sustainable Building, is part of Broad Group which also works on a number of different products (i.e. Air Conditioning Equipment, Air Quality Technology, etc.). Their website has very minimal details, but claims that their buildings can withstand magnitude 9 earthquakes. They also allege that they are 5 times more energy efficient, have 20 times purer air, and use 6 times less material. To find out more about Broad Group, you can visit their website at the following link:

Broad Group Website

In addition to this, construction has begun on the soon-to-be tallest building in the world, the aptly named Sky City.

Sky City. Photo Credit: Web Odysseium

Sky City, which will cost less than 1 billion dollars US, will rise to a height of 838 meters (10 meters taller than the Burj Khalifa). The building is set to be completed in April 2014, less than a year before the start of construction. To put that into perspective, the Burj Khalifa took more than five years to build and had a total cost of 1.5 billion dollars US (see CNN Report).

It is quite amazing to think that the processes used in construction have been nearly stagnant for thousands of years. The Egyptians employed a similar style of on-site construction when they began building the pyramids. Over the years, construction times for the worlds largest structures have reduced from 20 years to just over 5. With the new prefabricated structures, construction times have been reduced to less than one year, a truly magnificent feat. This allows engineers to think both ‘bigger’ and ‘higher’ as the cost of constructing buildings using the new technique is greatly reduced.

The concept of prefabrication is not new, but employing it at such a scale is quite revolutionary. It takes the work typically performed on the construction site and moves it into the much more comfortable, controlled environment of the manufacturing plant. As this industry grows, there will be much debate as to which construction process provides the safest, well-rounded structures. Either way, the entire industry is in need of a much needed facelift, and this new process may be just the spark it’s been waiting for.