Posted on

Out With The Old and In With The New

Precisely placed explosives have traditionally been used in the demolition of old buildings. Over the years, the process has been refined, and buildings are now demolished with minimal disturbances to adjacent structures. An example of this is the Landmark Tower in Fort Worth, USA, which was demolished in 2006. The below video captures the elegance of the buildings demolition:

Despite advances in the industry, there are many issues associated with this type of demolition. For one, the explosions cause dust and debris, and the clean up process can be quite gruelling. In addition, buildings demolished in dense urban areas run the risk of causing damage to nearby structures. In 1997, the implosion of the Royal Canberra Hospital in Australia killed a spectator after debris was thrown over 400m (Canberra Times Report).

As a result, researchers in Japan have developed a safer process for demolishing buildings in dense areas. Instead of imploding the building, it is disassembled from the top down. A multi-storey scaffolding system is used to hide the demolition of individual floors. Columns and beams are removed, and temporary jacks are used to lower each floor, leading to minimal disturbances to nearby infrastructure. The process can be seen in this CNN report:

This process, although slow and costly, does circumvent much of the risk traditionally associated with building demolitions.

Recycling Demolition Waste

One of the biggest concerns with demolishing older structures is disposing of the old material. To deal with this, the crushed concrete by-product of demolition is now being collected, cleaned and reused as aggregate in new concrete structures (Concrete Recycling). This process provides a number of benefits, including: a reduction in disposal and transportation costs, minimal project carbon footprint, and an increase in the projects efficiency as the aggregate can be re-used directly on site.

However this process is impractical and cannot be used in the majority of construction projects. In addition, a tremendous amount of water is used to prevent dust from the demolition. As a result, researchers have been looking to refine the process.

Omer Haciomeroglu, a recent graduate of Umea Institue of design in Sweden, has developed a revolutionary design for recycling concrete on site (International Design Excellence Awards). The idea is simple: by pumping high pressurized water, the concrete is crushed into smaller pieces, and the the water-concrete mixture is collected. This slurry is then filtered, and all the aggregate retained from the process is sorted and bagged on site. The water from the slurry is later used as grey water to clean the site after demolition. By not using highly destructive methods, the reinforcing bars can be recycled for future use.

New Concrete Vacuum Creates “Clean” Solution to Concrete Recycling. Photo Credit: Gizmodo

This product, despite only being in the concept stage, is the catalyst that the industry needs. As new ideas for safer, more environmentally friendly processes emerge, the risk associated with building demolition can be mitigated, and future disasters can be avoided.

Posted on

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.

Posted on

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.