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The Future of Skyscrapers in Western Europe

Countries in both North America and Asia have seen a recent influx of new skyscrapers. Europe on the other hand, has fallen behind in this respect. The Burj Khalifa, in UAE, is almost two and a half times taller than the tallest skyscraper in Europe, Moscow’s Mercury Tower.

A number of European cities have traditionally limited the construction of skyscrapers to areas outside the downtown core. Examples of this include Canary Wharf in London, as well as La Defence in Paris (Forbes). However, cities that were heavily bombed during WWII have adopted a more centralized model; Frankfurt is home to over thirty buildings that are above 100m (329 ft) tall, most of which are located in the downtown core.

Frankfurt Skyline. Photo Credit: WSD Blog

London Tower Reaches New Heights

London has recently undergone a transformation, with a number of tall towers being built in the downtown core. The tallest tower, known as The Shard, completed construction in 2012. This 72 storey, 306m (1004 ft) tall building plays host to the tallest observation deck in Europe. The Shard is currently the tallest building in Western Europe, and the second tallest in the entire continent (The Shard).

The Shard in London Adjacent to Tower Bridge. Photo credit: Safe and Stand

The vision for the tower was to blend the new with the old, and avoid overshadowing the cities iconic landmarks. It can be argued from the above photo that this has been achieved.

Paris’ New Look

The recently built tower in London will not boast the record of Western Europe’s tallest skyscraper for much longer. Developers in Paris recently attained approval for the construction of two 320m (1050 ft) tall twin towers. The two towers will be located in the La Defence district, with a project construction cost of $4 billion. In an effort to preserve the historical significance of Paris however, these buildings will fall short of the Eiffel Tower which stands at a height of 324m (1063 ft) (Bloomberg). The buildings are scheduled for completion in early 2019 (European Estate).

Proposed Twin Towers in Paris’ La Defence Region. Photo Credit: European Estate

These skyscrapers are the first example of multi-use towers in Paris. They will play host to luxury apartments, offices and a five star hotel. This model has been adopted in cities such as Dubai, and has proven to be quite successful. However, many people believe that investors will be wary of this development. A recent study projected that office use in Paris will drop by twenty percent this year (Bloomberg). The building developer, Heritage Group, believes that these towers will create a new market within Paris. Alexander Kraft, chairman of Sotheby’s International Reality for France & Monaco, stated “This complex will offer services that are just not available on the Paris market at the moment. Owners of property would have access to a wide array of hotel services such as maid service, room service, etc. If it works, it can initiate the creation of a new market” (European Estate).

The Reality

There is an active debate regarding the development of tall towers within historic European cities. Historians argue that the large structures will overshadow the small, historically significant regions of the city. On the other hand, many believe that these towers will not only modernize European city skylines, but will provide a new perspective (and better view) of all the great history that the city has to offer.

It is important that cities proceed with caution in this respect. Although I support the construction of new skyscrapers, care should be taken to ensure that they are integrated with the existing infrastructure. Examples such as The Shard in London prove that this is possible. With the continuing success in these endeavours, more skyscrapers will be approved for construction, giving Europe a strong foothold in the race for the tallest and most spectacular skyscraper.

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Tower Infinity: The Invisible Skyscraper

The continuing battle for skyscraper supremacy has reached new heights with the completion of Shangai Tower in China. At 632m (2073 ft), it is the second tallest building in the world, just short of the 830m (2723 ft) tall Burj Khalifa (CBC News)

Designers in South Korea however have taken a different approach: instead of focusing on the height of the structure, why not showcase the technological capabilities of the nation. The result is the world’s first ‘invisible’ skyscraper.

Tower Infinity will be constructed in Seoul, South Korea to a height of 450m (1476 ft), making it one of the tallest buildings in the world and the sixth highest tower. The construction was recently approved by the government, but a date has not yet been set for this ambitious project (CNN). The design of the tower was completed by GDS architects, and will feature the third tallest observation deck in the world, a theatre, a roller coaster, various restaurants, and a water park (Inhabitat).

Located near the Incheon International Airport, Tower Infinity is set to become the new face of Seoul. According to GDS architects, “Instead of symbolizing prominence as another of the world’s ‘tallest and best’ towers, it sets itself apart by celebrating the global community rather than focusing on itself. The tower subtly demonstrates Korea’s rising position in the world by establishing its most powerful presence through diminishing its presence.” (GDS)

The structure itself will consist of a series of blending shapes ranging from diamonds to triangles (Good Times). However, what sets the proposed tower apart is the ‘smart’ facade which will render the building invisible to pedestrians at ground level.

How the Magic Works

Cameras will be installed at three different heights and on six different sides of the tower. These cameras will record the building’s surroundings in real-time. These recordings will then be streamed to the 500 rows of LED screens built into the facade of the tower, each edited to seamlessly connect with one another.

By projecting real-time images from the back of the building onto the front, it will create the illusion that the building is in fact, invisible. In addition, the level of transparency can be varied, depending on the desired effect (CNN).

Varying Levels of Transparency for the Proposed Tower Infinity. Photo Credit: CNN

However, this concept could be used for a number of different applications. For one, the TV screens could be used as billboards, creating the worlds tallest advertisement. In addition, the screens could be used to broadcast real-time world events. The possibilities seem endless.

Similar Projects Around the World

The concept of an invisible skyscraper may seem to be novel, but similar projects have been attempted around the world. In Sweden, the Mirrorcube hotel uses a mirrored facade to render itself invisible to all those walking through the forest setting.

Mirrorcube Hotel in Sweden. Photo Credit: Telegraph

The hotel room measures 4 meters in each direction. The room includes a large bed, bathroom, lounge, and rooftop terrace. The mirrored facade allows the structure to co-exist seamlessly with the surrounding environment: an effect that the Tower Infinity is looking to replicate. In addition, a special mesh that is only visible to birds has been installed to protect the wildlife in the area (Telegraph).

The Next Big Project

Countries all across the globe are currently vying for infrastructure supremacy. This has lead to investments of billions of dollars in developing higher, more technologically advanced structures. This trend will increase exponentially as the global economy emerges from the current recession. As a result, the next decade could produce truly spectacular structures.

For more photos of the Infinity Tower, see the Structural Digest Gallery.

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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.

WTC Mem
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“.

Perseverance

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.

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2013 New York City Bridge Conference

On August 26th and 27th, the world’s top bridge engineers and architects congregated to New York City for the 2013 New York City Bridge Conference. This conference was first hosted by the Bridge Engineering Association in 2003, but has quickly emerged as one of the leading bridge conferences in the world.

This year, the conference played host to a number of esteemed guests and industry leaders. The lead designer for Istanbul’s new Bosphorus Bridge presented the design and discussed the current specifications for long span suspension bridges. In addition, Thomas Lavigne, a partner in Lavigne Cheron Architects, presented his design for the new Jacques Chaban-Delmas lift bridge in Bordeaux, France. The projects are illustrated below.

Bridge
The Third Bosphorus Bridge (left) and the Jacques Chaban-Delmas lift bridge (right). Photo Credit: Today’s Zaman and the American Society for Civil Engineering.

The conference also included many other speakers from around the world. The topics discussed include: Cable Supported Bridges; Bridge Rehabilitation; Seismic Analysis and Design; Bridge Monitoring; and Bridge History and Aesthetics.

Innovation in Bridge Rehabilitation

Corrosion of reinforcing, concrete degradation and concrete spalling are the three main concerns when dealing with concrete bridges. Traditional technologies employ a host of testing machines, causing the process to be quite inefficient; typically only 1000 sq. ft. of bridge deck can be inspected within one hour. Not only does this inefficiency increase the total cost of the project, but it creates traffic congestion and puts the worker’s lives at risk.

Researchers from Rutgers University have now developed a fully autonomous robotic non-destructive-evaluation platform. This product is an ‘all-in-one’ bridge inspection tool, and has the potential to drastically change the face of the industry.

The new product comes equipped with four resistivity probes, two surface imaging cameras, a laser scanner,and a GPS tracking system. This allows the robot to conduct all necessary testing, including: impact echo; ground penetrating radar; ultrasonic surface waves; and electrical resistivity testing. Furthermore, it is designed to move laterally and to turn at zero radius along a pre-set inspection path.

This product is able to inspect 4000 sq. ft. of bridge deck per hour (four times faster than traditional techniques). It also requires fewer workers on site, providing a higher level of project safety and efficiency. In addition, real-time data analysis is undertaken in a nearby van, allowing engineers to quickly address any concerns that arise.

Rapid Replacement of US 6 Keg Creek bridge

In an effort to reduce traffic congestion and fatalities during bridge construction, the US Congress approved the formation of the Strategic Highway Research Program (SHRP) in 2005 (Transportation Research Board). The SHRP has since developed an aptly named Accelerated Bridge Construction (ABC) process, which makes use of pre-fabricated modular construction.

The US 6 Keg Creek Bridge replacement in Iowa took place in 2011 and was a pilot project for the new system. This project would typically take six months to complete. However using ABC, the replacement took only two weeks. The fourteen day bridge assembly was made possible by the use of an on-site fabrication plant. However, this could not be done in densely populated areas. A time lapse of the bridge replacement is presented below.

The old bridge was demolished in just one day, using what Bala Sivakumar of HNTB Architects refers to as a “chop and drop” system. The cost of the replacement totalled $231 per sq. ft..

To connect the ‘lego’ pieces, joints were filled with ultra high performance concrete (UHPC). This created full moment connections, emulating a typical cast-in-place construction. The use of UHPC also allowed the six inches of overlapping reinforcing steel at joints to fully develop. However some problems did arise when applying the UHPC to the old concrete. This was resolved by installing post-tensioned rods which created compression within the joints.

Further Advancement

The new concepts and ideas discussed at the conference show how advanced the industry has become. However, there are still many aspects of bridge engineering that require improvement and optimization. As the industry grows, new research will continue to bring forth ideas that revolutionize construction practices. It is therefore imperative that conferences continue to occur, providing a platform for researchers to both share and inspire.

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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.

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Cardboard: An Alternative Construction Material

Cardboard, first invented in 1817, is generally used as a packaging material (A History of Packaging). In 2001, the Department of Trade and Industry (based out of the UK) began looking into the viability of using corrugated cardboard as a building material. The research identified several important traits: cardboard can be easily recycled, has low impact on the environment, is easy to manufacture, has good insulating properties, and can have an attractive texture. Finally, it’s inexpensive, making it an appealing option for temporary construction (Buro Happold).

As a result of these findings, new projects have emerged throughout the world. An addition to Westborough Primary School (UK) was made using only cardboard materials while aiming for zero carbon emissions. The building was constructed in 2002 and serves as an after school club, a kitchenette, a storeroom and a toilet block. After a decade, the structure is reported to be in great condition (The Guardian). The success of this project acts as a proof of concept for the growing cardboard construction industry.

New Westborough Primary School Building. Photo Credit: The Guardian

In addition, an Australian company has recently developed a new product called Ceramiboard. Ceramiboard is composed of traditional cardboard with a special coating. This coating improves the cardboard’s fire-rating and strength, allowing it to be used for fire rated wall assemblies, ducts, strong cardboard boxes and general purpose wall panels. A 14mm thick, three layered wall assembly using Ceramiboard has a compressive strength of 0.45 MPa (65 psi) and a flexural strength of 4-8 MPa (580 – 1160 psi) (Ceramiboard).

The Cardboard Revolution

World renowned architect Shigeru Banu is an adamant supporter of cardboard as a building material. In 2012, he designed a cardboard pavilion in Moscow’s Gorky Park using specially treated cardboard columns. This special treatment provides the structure with a surprisingly long life span (Disegno Daily).

Cardboard Pavilion. Photo Credit: Architizer

Ban has also recently finished a new cardboard cathedral in New Zealand. The original Christchurch cathedral was destroyed during the February 2011 earthquake which claimed the lives of 185 people. A new cathedral was needed, but would take a considerable amount of time to construct. Ban proposed that a temporary cathedral be built using cardboard as it is economical, easy to construct, and eco-friendly.

Christchurch’s New Cardboard Cathedral. Photo Credit: Daily Mail

The cathedral’s platform is made up of shipping containers which provide extra rooms, storage and side chapels. The A-frame roof structure tapers towards the front and is composed of 98 interlocking cardboard tubes which weigh 120 kg each (BBC News). A polycarbonate roof covers these tubes, protecting them from moisture (Make Wealth History).

The total cost of the cathedral is $3.3 million, and the structure has an estimated life-span of 30 years (Daily Mail). However, Ban argues that this could easily be increased to 50 or more if the building is well maintained. The maintenance of such a structure is quite simple when compared to traditional construction, and is one of the most economical features of the new cathedral.

As the cardboard construction industry grows, the product will be refined. This technology has the potential of mass producing affordable buildings for both temporary and permanent use, and will be important in future disaster zones. However, further testing needs to be done to determine the feasibility of these structures in the long term.

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Toronto’s Union Station Revitalization

During the 19th century, rail companies used separate stations located throughout the City of Toronto. However in April 1904, a great fire destroyed much of the existing infrastructure. The rail companies, devastated by the fire, proposed the construction of a single train station that would serve all train companies passing through the city. As a result, the construction of Union Station, which began in 1914, was completed in 1927 (City of Toronto).

Union Station in 1927 After It’s Opening. Photo Credit: The Canadian Encyclopaedia

Presently, Union Station serves 250,000 passengers a day (City of Toronto). Services connecting into Union Station include Via Train, Go Train and Toronto Transit Commission (TTC) subways.

However, Union Station was not designed for such high capacity. For one, customers are often left to deal with long delays due to bottlenecking of passengers at platform exits (Metro News Article).  As a result, the city has embarked on an ambitious plan to revitalize the historic station, bringing it into the 21st century.

The Plan

The revitalisation, which began in 2009, has three main objectives: to improve the quality and capacity of pedestrian movement; to restore heritage elements; and to transform Union Station into a major destination for shopping and visiting. Once the revitalisation is complete, the overall gross footage of Union Station will be increased by 14 percent (Globe and Mail).

The proposed project will cost almost a billion dollars to complete. The City of Toronto is contributing $640 million to the project, supplemented with investments of $164 million by the Federal government and $172 million by the Provincial government (Urban Toronto).

Improved Train Platforms

The current train platforms do not allow for natural light, creating a rather depressing environment. The new Train Shed, pictured below, will allow natural light to flow onto the platforms and will provide a more aesthetic appeal for Ontario’s main transportation hub.

Proposed Platform Design. Photo Credit: Globe and Mail

The roof is to be constructed using three layers of glass. This glass will be specially treated to deflect sunlight, preventing solar heating of the platform. In addition, the side walls are designed to allow air to flow freely through the platform, while preventing rain water from entering (Globe and Mail).

Union Staion’s Iconic Great Hall

The Great Hall, located on the north side of Union Station, is the most iconic and well known part of the building. To preserve the history of this landmark, the hall will only receive small repairs. The historic hall will then be restored to its original grandeur, and shall continue to be the hallmark piece for the station.

New TTC Platform

The TTC subway platform at Union Station is unusually thin, and serves both the Yonge and University subway lines. As a result, a new platform will be added to the south side of the tracks, increasing the stations capacity. This new platform will serve the Yonge bound traffic, while the old platform will serve the University bound traffic (TTC).

New Platform Layout. Photo Credit: Globe and Mail

The Final Product

In addition to these major improvements, a number of smaller projects will be completed.

VIA rail’s Panorama Lounge has been re-constructed, and is now open to passengers (VIA Rail). The ‘moat’ that currently exists between Union Station and Front St. will receive a glass roof to create a comfortable environment for passengers. The underground PATH system, which consists of 28 km of underground pathways, will be expanded with a new route up York St., connecting with the existing tunnel at Wellington St.. Finally, a lower level shopping centre will be created underneath the central concourse, increasing retail space from 35,000 to 153,000 square feet (Globe and Mail). Construction is scheduled to be completed in 2015, in time for the Pan American games hosted in Toronto.

The revitalised station is the gateway to the heart of Toronto, and will be a major component of improving the cities image on a global scale for years to come.

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A Revolution in Bridge Repair

Today’s infrastructure is in disrepair, particularly our bridges. The issue, discussed in my previous post entitled The Age of Disrepair, has become a hot topic for discussion. As a result, research is being conducted across North America to develop new systems to find economical and environmentally friendly solutions.

Hannah Loring is a Civil Engineering graduate student at the University of Maine. Her research, under Professor Bill Davids, is focused on repairing the countries ageing bridge infrastructure. One of the major concerns with older bridges is weight capacity, as they were originally designed to withstand smaller, less frequent truck loads.

A proposed solution is posting weight limits on the bridges.  This will however cause traffic congestion. Alternatively, researchers at the University of Maine are developing a new product called a ‘polymer reinforced flexural retrofit system’.  This system uses strips of carbon and glass composites which are installed to the undersides of bridge decks using adhesive and concrete screws. The system increases the flexural capacity and lifespan of the bridge (Bangor News Report).

This product has the potential to revolutionize the way bridges are retrofitted. Professor Bill Davids suggests, “We’re giving a low-cost alternative for the short term that would increase the strength and durability of the bridge, prevent it from having weight [limits] posted, and allow the bridge to remain safe”. A typical deck replacement for a flat-slab bridge costs over $120,000. Using the composite strips, this can be reduced down to about $70,000. In addition, concrete beams reinforced with the polymer strips exhibit an increase in load carrying capacity from 15,000 lbs to 21,000 lbs (Bangor News Report). This research was presented at a recent press conference.

Press Conference Video

“Band-Aids” Aren’t Always The Right Solution

In some cases a full replacement of the bridge is required. Acrow Bridge, a company based out of the United States, specializes in prefabricated modular steel bridge solutions for permanent, temporary and emergency use. Acrow’s website claims that, “Through the simple addition of prefabricated modular steel bridge components, Acrow bridges are easily customized to the desired length, width and strength, allowing for diverse applications and uses”.

Acrow’s Temporary Bridge Being Used Adjacent to the Construction of a New Bridge. Photo Credit: Acrow Bridge

Acrow prefabricates the temporary bridge off-site, allowing for a quick assembly and minimal traffic disturbance. In addition, each section of these bridges can be re-used for different projects. Not only is this environmentally friendly, but it drastically reduces the overall cost. The product has been a huge success thus far. Bill Killeen, CEO of Acrow, said, “Consequently, more and more customers are expanding their inventory of modular steel bridges to deal with both emergency and scheduled repair work”.

There is no perfect solution for deteriorating bridges. However, with each passing day the process for repairing our bridges is being refined. If cities continue to take an active role in repairing bridge infrastructure using these technologies, bridge collapses may become a thing of the past.

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Electrified Concrete: Creating Smart Cities

Lightning Hitting San Fransisco’s Bay Bridge. Photo Credit: Daily Mail

The concept of electrified concrete is not new. In 1980, W. Hymer wrote a research paper outlining the advantages of allowing current to flow through concrete. These included: protecting against lightning, eliminating static electricity, environmental healing and radio frequency interference  (Concrete Construction). Despite this, little research was done to develop the concept.

Until now.

Researchers at  the National Research Council of Canada (NRC) have begun developing a concrete which allows electricity to flow freely through it. This “smart concrete” can be used to prevent ice from forming, detect micro-cracks, and create cyber secure buildings. The concrete is mixed using conductive aggregates, which allow current to flow freely through the concrete (Txchnologist). However, this technology is expensive, and would only be implemented on critical sections of road and for bridge decks. In these cases, the cost of implementing the system is overshadowed by the amount cities spend on repairs.

Electrified Concrete Could Create “Smart Bridges”. Photo Credit: Cement.org

According to NRC’s Rick Zaporzan, “With a few tweaks, it can be used for developing a crack-detection system if it’s hooked up to proper sensors that can monitor and interpret that data”. In addition, the concrete could be used to block electromagnetic signals from entering or leaving, creating a cyber secure building. Rick Zaporzan claims that, “The concrete can also be used to protect extremely sensitive medical equipment, and that’s a huge application” (Txchnologist).

Implementing “Smart Roads”

By allowing electricity to flow through concrete roads, vehicles will be able to “recharge” their batteries while driving. Researchers at Japan’s Toyohashi University of Technology have created a process, wherein current sent through concrete decks is able to power objects on the surface (so far they have used the electricity to light an incandescent bulb). Although the technology is in the early stages of development, it could be used to power electric cars, eliminating the need to pull over and recharge (Engadget). 

In addition, the Korea Advanced Institute of Science and Technology (KAIST) has developed a 24km strip of road which is able to supply specially made buses with power. Metal plates embedded within the road surface create electromagnetic waves, which provide electricity to the batteries built into each bus. This system eliminates the need for overhead wires, and allows buses to use significantly smaller batteries (CTV News).

The concept is explained in this short video:

Wall Street Journal Video

The possibilities for this product are seemingly endless. As cities begin to invest in smart infrastructure, more ideas will form, creating a much different world. Until then, however, it will remain a popular research topic for institutes around the globe.

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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.