Structural Digest welcome to my blog, structural digest – a collection of articles highlighting the structures around us. Like what you read? subscribe now. Latest PostsThe People Who Bring Bridges to LifeJuly 4, 2019The new Samuel de Champlain bridge opened to traffic on two very important days. The northbound lanes heading into Montreal were opened on June 24th, when the province of Quebec celebrates Saint Jean Baptiste Day. The southbound lanes heading to Brossard opened on July 1st, when Canada celebrates the founding of the country. View of the Samuel de Champlain Bridge (right), alongside the old Champlain Bridge (left). These opening days are symbolic of how important the original Champlain bridge, and now the Samuel de Champlain bridge, are to North America. According to Infrastructure Canada, this bridge is crossed 50 million times each year (https://www.infrastructure.gc.ca//nbsl-npsl/faq-eng.html). This translates to approximately 140 000 vehicles per day, or 5 800 vehicles per hour, making the crossing one of the most important bridges in North America. How does a 3.4 km long bridge, with a final price tag of around $4.5 billion, get built? A project of this scale requires an organized group of thousands of people to achieve such a feat of Engineering. For years these people have been spending their days, nights, and weekends, often in extreme temperatures and weather conditions, ensuring that each individual task gets done on time, and on budget. So, who are these everyday heros? There are many different roles that need to be filled to complete a project of this scale. To understand the range of specialties needed, consider the following groups of professionals who have contributed to the project: Construction workers: Build the bridge, piece by piece. Includes work on site and in fabrication shops.Construction Engineer: Coordinate construction works on and off the jobsite, ensuring the safety and quality of the works.Engineer of Record: Design the bridge by calculating the exact loading expected from traffic, and create a structural system that can carry these loads safely across the river.Independent Engineer: Check the design of the Engineer of Record, and spot-check the on-site works.Environmental Engineers: Create systems to protect the environment before, during and after construction. Geotechnical Engineers: Verify the condition of the soil and rock to ensure the bridge can rest on solid foundations.Durability Engineers: Ensure that all materials and methods used for construction are going to meet the durability requirements of the bridge, which includes 125 years with no major repair works.Quality Control Engineers: Verify the quality of the materials being received on site, and ensuring the quality documentation is filed per project requirements.Document Controllers: Coordinate and document millions of documents relating to every aspect of the project.Owners Engineer: Develop the overall concept of the bridge prior to awarding the project, in coordination with the Architect.Others: There are numerous other groups that participated in the project, including risk management, finance, law, asset management, etc. Within these professions, there is a large variation in the types of tasks required. Consider the role of the Engineer of Record (EOR). For the Samuel de Champlain bridge, the EOR consisted of T.Y. Lin International, Systra-International Bridge Technologies, and SNC-Lavalin. Members of the EOR field Engineering team. Photo credit ©Christian Fleury-CAPA pictures. From the pre-bid works to final completion, the EOR is constantly engaged on a wide range of different roles to ensure that the bridge gets built according to the project agreement and all relevant design standards. These roles include, but are not limited to: Help develop an estimate of the materials and cost of construction with the contractor, to provide a competitive bid to win the project.When the project is awarded, use the project requirements, design criteria and design standards to determine the size, shape, material and connection of the entire bridge.Independently check the work of the other partners in the EOR team, to ensure the quality and safety of the design.Work with the contractor to verify the method of lifting and installing each of these pieces.Provide construction site support to the contractor at every stage of the construction, as part of the certification process for the bridge. After the many millions of hours worked on this bridge, there is one final product that will last for at least the next 125 years. That translates to more than 6.3 billion vehicles trips, most of which will be made by people who are not even born yet. This single projection highlights the magnitude of what has just been accomplished in Montreal. The importance of every single person who contributed to the project cannot be overstated, and has helped deliver a bridge that Montreal, and Canada, can be truly proud of for generations. Members of the EOR team attending the bridge’s opening ceremony on June 28, 2019.... Read more...Engineering Better ConferencesJanuary 10, 2019How conferences can provide more value to Engineers Conferences provide a forum for industry experts to come together to discuss ideas and share progress. The traditional format of Engineering conferences resemble a series of lectures: speakers first present their work, after which the audience is allowed some time for questions. If the presentation runs too long, it comes out of the question period. This limits the academic potential of conferences, as Engineers are forced to sit and listen, while providing limited ideas or input. Often, conferences are attended by the same people each year, and have evolved into a forum for embellishing accomplishments. Attendees are not likely to recall the size of the prefabricated element that was erected, nor is this information necessarily useful to them. However, if everyone at the conference engages in conversation about the innovative technique that was used to erect the panels, and how it could be improved, then attendees can gain value from the conference. Question period at the CSCE SMSB 2018 Conference in Quebec. In addition, more workshop type sessions should be developed to nurture curiosity and teamwork, in order to inspire one another. These workshops should first introduce the major theme, such as the use of high-performance concrete. Following this, Engineers should be given a problem that must be solved based on the theme of the workshop. Working through and discussing these problems will not only foster creativity in Engineers, but highlight new opportunities or tools that Engineers can use in their own practice. Change needs to start at the conference organizational level. Organizers need to put less emphasis on big dinners, expensive evening events and venues. This in turn will reduce the cost of attending the conference, allowing more engineers from a broader range of backgrounds to attend. In addition, reducing the number of speakers will provide more time per session for open discussion. Each session should have some main topics of conversation, that are supplemented by specific projects from the chosen speakers. No rehearsed speeches, and no wordy PowerPoint slides. If conferences are able to foster good discussions, they can provide real value to attendees. This will then motivate more Engineers to attend, building a stronger and more knowledgeable community. Have any thoughts on how conferences can be improved to provide more value for attendees? Please feel free to provide input in the comment section below!... Read more...Pushing the Boundaries of Bridge ConstructionOctober 10, 2018Humans have been building bridges for thousands of years. At first, they were built using trial and error. Recently, humans began to use math and physics to create bigger, safer, and more economical structures. Paired with new materials, economic prosperity, and the development of the Bridge Engineering profession, this has led to the creation of some truly magnificent structures. When the Brooklyn Bridge was completed in 1883, it had the longest main span (distance between vertical supports) in the world. Since then, this feat has been surpassed hundreds of times. In 1937, using the same type of support system, the Golden Gate Bridge was constructed with a main span that is 2.5 times longer than the Brooklyn Bridge. Around 60 years later, the Akashi Kaikyo bridge increased that by 1.5 times. The five bridges with the longest mains spans in the world are presented in the below table. All of these are suspension bridges, similar to the Golden Gate and Brooklyn bridges. The theoretical limit on the length of a suspension bridge is governed by the self-weight of the support cable and deck system. Theoretically, the longest possible length of a suspension bridge, using present day materials, is approximately 5 km. This is 2.5 times longer than the longest bridge built to date. However, there are many practical restraints that would make the construction of such a long span nearly impossible. In the past century, the materials and methods used for construction have developed at a slow pace, and there have been few significant changes in the general form of long span bridges. Some may believe that engineers have reached the peak performance of construction materials, while others may argue that the current base of knowledge is sufficient for the majority of bridges that society needs. So why would engineers continue to push the boundaries of bridge construction? Because, we are engineers – and that’s what we do! Engineers are always looking for ways to improve bridges, either by building them faster, cheaper, or safer. However, only a small group focus on a very interesting challenge – how to make them longer. In a recent paper (link to paper), an analytical model was developed using a numerical layout optimization procedure to study the theoretically optimal form that a very long span bridge should have. One of the most interesting concepts that comes out of this paper is the split-pylon form, presented below. This bridge is shown with a main span of 5 km, which is 2.5 times longer than the longest bridge ever built. This new structural form would be difficult to construct using present day techniques, as it may require significant temporary supports when erecting the split pylons. However, the final optimal form provides a brand-new artistic form for a bridge – similar to the forms that became popular after the development of suspension and cable stay bridges. This balance of engineering optimization and form need only find a balance with economy, to become a truly plausible option. At the very least, this paper significantly adds to our understanding of how long span bridges can be built using present day materials. It also offers hope to the bridge engineering profession, and opens up many new potential problems, and exciting challenges, that we get to deal with. Even if a bridge like this never gets built, it will help to inspire others to study the feasibility of new structural forms for long span bridges. And that, is very exciting!... Read more...Engineers: The Creators and Controllers of RiskAugust 13, 2018Engineers use scientific knowledge to push the boundaries of the physical world. but how risky is it? Engineering is a very dynamic industry, and the scope of what engineers do constantly changes. At the core, Merriam-Webster defines engineering as: “The application of science and mathematics by which the properties of matter and the sources of energy in nature are made useful to people” This is an incredibly broad description that encapsulates many activities. From building bridges to space stations, engineers design and build the visible (and more recently the non-visible) world around us. What this definition does not convey is that an engineer’s job is understanding and taking on risk. With every new bridge, the engineer of record uses their theoretical knowledge to design the structure to an acceptable level of safety. In modern times, this level of risk is defined in technical and regional design codes and specifications. In the past, however, the acceptable level of safety was defined based on the experience of the engineers involved. This has created some engineering folk tales, including one where clients were forcing engineers to stand underneath their new bridges during load tests. This ensures that the engineer is literally held accountable for any short-comings in the design. I have heard this tale in many different countries around the world, and hope it was not true! In modern society, a governing body licenses engineers by region. For each project, the engineer takes on the responsibility to protect the investment and safety of the public, client, and all stakeholders. As a result, “each engineer must walk a tight line between being a designer and a lawyer.” Each and every decision that an engineer makes can impact cost, schedule, and safety. It is therefore imperative that engineers understand the scope of risk that they are taking on, with relation to the project agreement. This is something that engineers, both junior and senior, can struggle with. In design-build contracts, for example, it is imperative that the scope of risk is understood by everyone, and maintained throughout the duration of the project. However, these lines can often get blurred when quick decisions are needed. It is at times like these that engineers must use caution in how they respond to each question, as small changes in wording can significantly impact the level of risk that engineers are exposing themselves, and their companies, to. Since understanding this aspect of engineering can often govern the way we work and interact with clients and the public, it is imperative that this be taught to engineers in school, and early on in their careers. This will not only help protect the public by maintaining accountability for risk, it will also protect our engineering firms from taking on unnecessary risk.... Read more...Bridge Engineering – The Lost ArtMay 31, 2018Like many, I grew up fascinated with how things work – how they are put together, how they stay together, who makes them – and how I can become involved with them. After some research (with books, dial-up internet time was restricted so my father would not miss a call), I found out my true calling – to be an Engineer. Of all the interesting and challenging engineering disciplines, I decided that I wanted to be a Bridge Engineer. To put it simply: we take a problem (river), add a requirement (need to cross said river), and come up with a solution (bridge). Believe it or not, in most cases designing the bridge and its components is not the hardest part – it’s having to build them fast, cheap, and sometimes beautiful (more on this last point later). As the American Civil Engineer, Arthur M. Wellington put it, An engineer can do for a dollar what any fool can do for two. This is the key to the engineering profession. We innovate to save society money, which increases the number of infrastructure projects, which leads to more innovation and cost-savings. It’s a wonderful cycle! But there is something that seems to be missing in the modern day definition of a Bridge Engineer. In the below image, we have a bridge. This was designed by an Engineer, and is a common form for a present day highway overpass – but not many people would refer to this bridge as beautiful. Many people believe that this can be solved, simply by adding a “Bridge Architect” to these projects. Indeed, the Ministry of Transportation of Ontario (MTO) has taken this to heart, by recently making it mandatory on some signature projects. The most famous example of this is the engineer turned architect, Santiago Calatrava. As shown below, he cares deeply of the artistic originality of his bridges. However, this all comes at a large price tag – which is always paid for by tax payers. For example, the Peace Bridge was built for $24.9 million, and construction was delayed by 1.5 years. In addition to the high initial cost, the city has needed to repair broken windows ($152 K) and install new lights ($700 K), partly due to design problems (read more: Calgary Herald). This seems to be a recurring issue with Calatrava projects (read more: D Magazine). Luckily there is a solution, and it’s very simple – education. Engineers study long and hard for years to master the physics behind bridge structures. However, very little time is put aside to teach students how to use this knowledge to create beautiful structures. As engineer David Billington put it, the art of bridge engineering is to balance form, function and economy. If you need proof, consider the Salginatobel Bridge shown below, designed by Bridge Engineer Robert Maillart. This bridge was the cheapest solution submitted, and for this reason only, was it built. Because Maillart had studied both the physics and form of bridges, he was able to create this masterpiece. But this is an extreme case. Consider this simple flyover bridge in Ontario. It was clearly not designed to be a signature bridge – but the attention to detail and form paid by the Bridge Engineer resulted in both an economical and arguably beautiful structure. Therefore, it is essential that bridge engineers stop selling their services as a commodity, and start re-discovering the influence that a good Bridge Engineer can have on society. This must start in the classroom.... Read more...Why we need a New Champlain BridgeFebruary 20, 2018The new Champlain Bridge corridor project in Montreal, Canada will cost up to $4.5 billion, and is planned for completion on December 1, 2018. But what’s wrong with the current bridge? Why was the decision made to build a new one, with such a large price tag? Spark-Notes (Easy Read) This section provides a quick, non-technical summary of this post. For more details, including some more technical information, continue to the following section. Current Champlain Bridge, open to traffic in 1962. Designed by engineers at SNC. Designated a life-line route off the island during emergencies. A 2011 report found that the main span was in good condition, but the concrete girders were deteriorating faster then expected. If one of these beams fails, the bridge could collapse. If the new bridge is finished on time, experts predict that a total of $550 million will have been spent on repairs. In October 2017, experts announced that it would cost an additional $250 million to keep the current bridge in service until 2020. As a result of this assessment, and after years of discussions, the government of Canada finally decided to proceed with construction of the new Champlain Bridge. Stay tuned for a future post on the construction of the New Champlain Bridge! Detailed Notes (Technical) This section provides more details and technical information, expanding on the points discussed in the spark-notes section. Condition of the existing bridge For years, experts were discussing potential options for repairing or replacing the existing bridge. However, the findings from the study conducted by the engineering firm Delcan (see full report) was the catalyst that started the process of designing and building the new bridge. The study was commissioned in August of 2010 to determine the current state of the Champlain Bridge. Although the bridge is considered a lifeline for the island of Montreal, it was found that the bridge would not be able to withstand extreme seismic events. The steel main span superstructure was found to be in relatively good condition, but the prestressed concrete girders, used for the approach spans, exhibited significant deterioration from the salt water running off the bridge roadway. The condition of the steel reinforcement in these girders cannot be determined, due to the potential dangers of damaging the pre-stressed strands. However, there is evidence of damaged and broken strands inside the concrete. The report also found that failure of the edge girders could lead to the progressive collapse of the bridge. These findings confirmed that critical repair work was needed on the existing bridge in order to maintain its safety in service. However, the cost to repair the bridge over the next 40 years was found to be equal to the cost to maintain the existing bridge for 15 years while building a new bridge. This point made it very clear to all parties involved that a new bridge was needed – and fast. Repair work needed At first glance, the current Champlain bridge looks like it is using every bridge rehabilitation technique ever invented. For civil engineering students at the city’s various universities, it would be a perfect case study, and an easy field trip. Sensors have been placed across the length of the entire bridge, to monitor its behaviour and deflection during service. In addition, the following repair techniques have been applied: A total of 74 steel truss supports have been installed under concrete edge girders, found to be in critical condition. External post-tensioning applied longitudinally along the edge girders. External post-tensioning applied transversely along the pier caps. External fibre reinforced polymer (FRP) wrap applied applied to the exterior of many girders. Assuming that the new bridge is delivered on schedule, the total repair bill is expected to reach $550 million (CBC). But with the majority of repairs completed on the existing bridge, and the new bridge planned for completion in December 2018, it seems that Montrealers can rest assured: The life-line crossing across the Saint Lawrence – one of the busiest bridges in Canada – will continue to be a safe choice for everyone. For more photos, visit: Existing Champlain Bridge Photo Album For more information, see below resources: https://www.bridgeweb.com/New-reports-highlight-latest-action-needed-at-Champlain-Bridge/3691 http://www.nrcresearchpress.com/doi/pdf/10.1139/l96-941 https://www.theglobeandmail.com/news/national/champlain-bridge-is-falling-down-montreal-pays-for-past-penny-pinching/article15699180/ http://montrealgazette.com/news/local-news/holding-it-together-on-the-champlain-bridge... Read more...Revolutionizing the Bridge Replacement IndustryJanuary 6, 2014The goal of every bridge replacement project is to minimize traffic disruption. Although this can be achieved using temporary structures, it results in high construction costs. More recently, modular construction has been used to cut down the on-site construction time. However this method still significantly impacts traffic flow. A new technique, known as Accelerated Bridge Construction (ABC), has been developed to mitigate traffic disruption. This process begins with the construction of the new bridge superstructure alongside the existing bridge. Once this is completed, the existing bridge is quickly demolished and the new bridge is slid into place. The final few pieces are installed, and the bridge can quickly reopen to traffic with minimal disruption. This procedure is outlined in detail by the Iowa Department of Transportation: There are a number of projects throughout the United States that are using this new technique. Michigan’s Department of Transportation (MDOT) is finalizing plans to replace three bridges this year using this process (M Live). MDOT spokesperson John Richard stated, “You’ll definitely see a lot more bridge slides taking place just because of the less impact on traffic. It’s really changing the industry. All the engineers at MDOT are very excited” (M Live). New York’s Department of Transportation has already constructed a number of bridges using this process. The construction of the I-84 bridges, which began in June, was completed in October of last year. Despite the length of the project, the actual replacement time totaled 18 hours for each bridge, occurring over two weekends. This resulted in savings of $4 million dollars (Roads Bridges). You can view the time lapse construction video of the bridge here: Accelerated Bridge Replacement It is evident that the use of ABC as a bridge replacement technique will increase in the coming years. However, it is important that researchers around the world continue to develop more efficient ways to replace the worlds ageing infrastructure. This includes reducing construction time, reducing costs, mitigating the effects on traffic and recycling materials from the demolished bridges. For more information regarding ABC see the brochures recently published by Aspire Bridge: Part 1 – Winter 2013 Part 2 – Spring 2013 Part 3 – Summer 2013... Read more...The Great White “Vanilla” NorthNovember 4, 2013On October 27, the well known street artist Banksy posted a short piece on his blog describing the new One World Trade Centre building as “Vanilla”. Banksy claims that the new tower is a betrayal to those that lost their lives on September 11. The backlash was swift as numerous news outlets, including the BBC and the NY Daily News, have criticized the article. One of the comments Banksy makes is that the new tower is “something they would build in Canada”. But does this statement have any merit? Is Canada’s architecture something to mock? Oh Canada Having claimed the title of the worlds tallest tower for 34 years, the CN Tower has garnered both praise and criticism. On the one hand, it attracts millions of tourists each year, and is one of the top attractions in the country. On the other hand, critics have often identified the tower as an eyesore. Colin Vaughan, an architect and political specialist for CityTV from 1977 to his passing in 2000, claimed: “The first disappointment comes at the main entrance. There’s no sensation of arriving at the base of a tall structure to be overwhelmed by the vision of the tower ahead… But none will experience the unique sensation, the vertigo and the straight excitement which should accompany a visit to a structure of this scale” (TorontoIST). This aside, the CN Tower is one of the American Civil Engineering Societies Seven Wonders of the World and is second place in the world federation of towers (CN Tower). There can be no doubt, this icon is a masterpiece that has put Canada on the map. Award Winning Architecture According to the official website, the Emporis Skyscraper Award is the world’s most renowned prize for high-rise architecture and has been awarded on an international basis every year since 2000. In 2012, the Emporis Skyscraper Award was given to the Absolute World Towers (also known as the Marilyn Manroe Towers) in Mississauga, Ontario (Emporis). The Bow building in Calgary, Alberta is the tallest office building in Canada outside of Toronto. In 2012, it finished fourth in the Emporis Skyscrapper Award and was also ranked in the top ten architectural projects of 2012 by Azure Magazine (Azure). Bridges Eh? Canada is also home to some truly spectacular bridges. The Peace Bridge in Calgary, Alberta was ranked in the top ten architectural projects of 2012 by Azure Magazine. In addition, CCN composed a list of the top 24 most spectacular bridges in the world, and both the New Brunswick Hartland Bridge and Confederation Bridge in Prince Edward Island were among them (CNN) Producing World-Renowned Architects Canadians can also be proud of the fact that many esteemed architects around the world are Canadian. Frank Gehry was born in Toronto and was revered by Vanity Fare as the most important architect of our age (Vanity Fair). Gehry has designed iconic buildings around the globe, including the famous Guggenheim Museum in Bilbao, Spain. Back in Canada, he designed the new addition to the Art Gallery of Ontario, which has been given outstanding reviews by architects around the globe (NY Times). Final Thought As Canadians, we all agree that everyone is entitled to their own opinion. I will not say that Banksy should take back what he said, nor will I attack him as an artist for having an opinion. However, this article has provided you with enough information to allow you to formulate your own opinion regarding the amount of “vanilla” architecture in Canada. There is much to be proud of as Canadians, and I believe that the quality of architecture in Canada is something that speaks for itself. For an indepth look at various other Canadian masterpieces, see the recent article by The Glove and Mail.... Read more...Christchurch’s New Shipping Container MallOctober 25, 2013On September 4, 2010 a magnitude 7.1 earthquake struck New Zealand’s third most populous urban area, Christchurch. Despite the damaged infrastructure, no casualties were reported. On February 22, 2011, nearly six months after the first earthquake, Christchurch was struck with a magnitude 6.3 earthquake. The epicentre was located close to the city centre and at a depth of just 5 km (3 mi). The shallow depth and previously weakened infrastructure lead to the collapse of many major buildings within the city and the death of 182 people (NZ Police). The six storey Canterbury Television (CTV) building, which was declared structurally safe after the 2010 earthquake, collapsed and killed 115 people. A report released by New Zealand’s Department of Building and Housing after the collapse claimed that the structure, built in 1986, was not up to either previous or current standards (New Zealand Ministry). The aftermath of these two earthquakes brought the city to a halt, and a ‘Red Zone’ perimeter was established to keep people away from the damaged infrastructure. However, the city of Christchurch has since made huge progress in bringing life back into the city centre. As part of re-building the city, architects and engineers have used the blank canvas to develop new, cutting edge building techniques. In my previous post entitled “Cardboard: An Alternative Construction Material“, I profiled the new cathedral that was constructed out of cardboard. In addition, a new shopping complex has been constructed in the city centre using recycled shipping containers. The project, which was completed in just eight weeks, has help bring life back into the city. The construction and opening of the shopping complex are presented in the following documentary.... Read more...The Future of Skyscrapers in Western EuropeOctober 12, 2013Countries 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. 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 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). 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.... Read more...Tower Infinity: The Invisible SkyscraperSeptember 26, 2013The 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). 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. 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.... Read more...One World Trade Center: Rebuilding From the AshesSeptember 11, 2013There 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. 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. 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.... Read more...2013 New York City Bridge ConferenceSeptember 4, 2013On 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. 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.... Read more...LEED-ing the Way To a Better FutureAugust 29, 2013In 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). 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.... Read more...Cardboard: An Alternative Construction MaterialAugust 25, 2013Cardboard, 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. 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). 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. 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.... Read more...Toronto’s Union Station RevitalizationAugust 19, 2013During 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). 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. 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). 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.... Read more...A Revolution in Bridge RepairAugust 15, 2013Today’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 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.... Read more...Electrified Concrete: Creating Smart CitiesAugust 12, 2013The 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. 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.... Read more...Out With The Old and In With The NewAugust 7, 2013Precisely 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. 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.... Read more...Modular Structures: A Lesson from LEGOAugust 5, 2013With 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). 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). 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.... Read more...The Age of Disrepair: What Do We Do With All These Bridges?August 1, 2013The issue of ageing infrastructure has become a serious concern in countries throughout the world. Bridges built in the past century have begun to crumble causing serious injuries, and in some cases death. In 2007, a bridge in Minnesota collapsed, killing 13 and injuring 145 people (I-35W Bridge Collapse) .Below is a video of the bridges collapse: As a result, an investigation was conducted by the Federal Government of the United States to determine the cause of the collapse. In addition, the National Transit Safety Board was created to help improve the state of infrastructure and prevent future collapses. However, it seems that this issue has not been eradicated. During a speech in Galesburg, Illinois, President Obama stated, “We’ve got more than 100,000 bridges that are old enough to qualify for Medicare” (The Hill Report). According to a report released by Transportation for America, “11% of all bridges in the US are structurally deficient”. Considering that Americans make 260 million trips across bridges each day, this is a major issue (T4 America Report). North of the border, Canadians are facing similar problems. A report released by Statistics Canada in 2007 stated that, “The average age of bridges went from 21.3 years in 1985 to 24.5 years in 2007, an increase of 3.2 years” (StatsCan Report). The province of Ontario has the third oldest bridge infrastructure in Canada (after Quebec and Nova Scotia) and its ailing bridge infrastructure has received a high degree of media attention. In Toronto, the capital of Ontario, the Gardiner Expressway has been identified as in need of serious repairs. The Gardiner is a major artery in Toronto’s downtown core, and a number of plans have been proposed to help rehabilitate it’s ageing bridges. However, the cost is quite steep. A current estimate puts the cost of repairing the bridge at $505 million (Globe and Mail Report). It is well known that repairing older bridges drastically reduce maintenance costs. As a result, many engineers are starting to develop creative solutions to help restore these bridges. Innovation, unfortunately, comes with a price tag. As cities face more funding cuts, engineers are forced to use cheaper, less effective techniques to restore bridges. Professor Paul Gauvreau of the University of Toronto states, “When engineers are repeatedly requested to implement yesterday’s solutions – that is, not to innovate – engineering becomes a mere commodity that can be bought and sold at the lowest price” (Globe and Mail Report). As is often the case, these low-cost repairs are not very effective, and can lead to higher repair bills in the future. A number of solutions have been proposed in the last few years that could potentially save cities millions of dollars on their repair bills. Some of these solutions include increasing the frequency of inspections, providing better drainage to current bridge decks, using domes to protect the bridge from rain and snow, and installing steel mesh beneath the bridges to catch any falling concrete (National Post Report). These solutions, however, are not always practical. More research needs to be done to find cost-effective repair techniques. Researchers all across the world are investing time and funding to help develop better, more efficient procedures for rehabilitating old bridges. As this research progresses, it will be interesting to see which solutions are adopted by the industry. In the meantime, cities will continue to pursue a ‘band-aid’ response to bridge deficiencies, leading to a higher potential for future accidents.... Read more...The Future of High Rise ConstructionJuly 26, 2013In 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, 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.... Read more...
