• 9/11: Twin Towers collapse9/11 Conspiracy Theories Debunked: 20 Years Later, Engineering Experts Explain How the Twin Towers Collapsed

    By David Oswald, Erica Kuligowski, and Kate Nguyen

    The collapse of the World Trade Center has been subject to intense public scrutiny over the last twenty years, prompting several investigations and spawning a variety of conspiracy theories. FEMA’s report was published in 2002, and NIST’s 3-year investigation produced a report which was published in 2005. While there have been critics of both reports, their explanation for the buildings’ collapse is widely accepted. They conclude it was not caused by direct impact by the aircraft, or the use of explosives, but by fires that burned inside the buildings after impact.

  • InfrastructureMarine Sponges Inspire Next Generation Skyscrapers, Bridges

    When we think about sponges, we tend to think of something soft and squishy. But researchers are using the glassy skeletons of marine sponges as inspiration for the next generation of stronger and taller buildings, longer bridges, and lighter spacecraft.

  • InfrastructureBuilding indestructible bridges

    A design process called “form-finding,” inspired by the natural world, could make possible a new generation of indestructible bridges. Form-finding enables the design of rigid structures that follow a strong natural form — structures which are sustained by a force of pure compression or tension, with no bending stresses, which are the main points of weakness in other structures.

  • InfrastructureFixing NYC’s aging infrastructure one engineering problem at a time

    How do you make sure aging bridges which are vital links in New York City’s transportation network are safe or keep the city’s sewer system from breaking down? These are among the questions that occupy Columbia University researchers, who have installed sensors to analyze vibration on some of the city’s bridges and in landmark buildings and museums, and have focused on the functioning of the city’s water system.

  • Mosul damMosul dam could collapse at any time, killing 1m people: Engineers

    Iraqi civil engineers familiar with the Mosul dam are warning of the dam’s imminent collapse, saying that the consequent death toll would likely be worse than earlier estimated. The engineers warned that the loss of life from a sudden collapse of the Mosul dam could be higher than earlier official estimates of 500,000, as many people could perish in the resulting mass panic. If the dam collapses, a 20-metre-high flood wave would hit the city of Mosul, then roll on down the Tigris valley through Tikrit and Samarra all the way to Baghdad.

  • Post-disaster rebuildingRebuilding a safer and stronger Vanuatu after Cyclone Pam

    By Wendy Christie and Brigitte Laboukly

    Three months ago Cyclone Pam swept across Vanuatu, leaving 75,000 people in need of emergency shelter and damaging or destroying about 15,000 buildings, including homes, schools, and medical facilities. Since then, one of the most hotly debated questions within communities and on social media has been about how Vanuatu can rebuild so that it’s safer, stronger, and more resilient to future cyclones. Achieving this is not as simple as you might think. The strength and safety of buildings is critical — especially when you are rebuilding in a cyclone-prone region. But housing in particular is about more than walls and roofs; it’s also about community, traditions, culture, and supporting the way people want to live. While the strength of buildings and their ability to withstand cyclones are very important, so too are the strength and resilience of the people of Vanuatu, who have been living with the annual cyclone season for generations. The reconstruction of Vanuatu needs a diverse approach that is not solely reliant on quickly prefabricated or engineered solutions, and which keeps people at the heart of the rebuilding process.

  • ResilienceNepal should use updated, upgraded building codes in post-disaster construction: Experts

    Urban planners and disaster experts who have been arriving in Kathmandu to inventory, assess, and make recommendations have been urging the Nepalese authorities to “Build it back better.” There are plenty of examples of post-disaster construction built significantly safer, using low-cost traditional materials and methods. Nepal has last updated its building code in 1994.

  • TunnelsUsing shotcrete to make tunnels withstand terrorist attacks

    Conflagrations and terrorist attacks are a threat for tunnels and bridges, so engineers are searching for ways to make tunnels and bridges as robust as possible. Construction materials, such as special types of high-performance concrete, which can partly absorb the impact of explosions, already exist, but due to their manufacturing principle, they cannot be made in any other shape than the slab, which cannot be used for cladding surfaces with complex geometries. A new type of shotcrete — which used to be considered impossible to manufacture — was created by scientists to render the structures more robust. Despite its high steel and synthetic-fiber contents, it can be sprayed on easily.

  • EarthquakesDisaster and recovery: The unexpected shall come to be expected

    By Vincent T Gawronski

    In the days following the Nepal earthquake, the media has been focusing on the heart-wrenching human interest and hero-tragedy stories, but what must be emphasized is that this disaster was anticipated. More importantly, we now have the tools and building technologies to mitigate the impact of even major earthquakes. The frequency of earthquakes has not changed over the past few million years, but now millions of people live in vulnerable situations. The unexpected must come to be expected. Much-needed humanitarian assistance must transition into long-term development efforts. Simply put, instilling a culture of disaster risk reduction, investing in hazard mitigation, building as best as we can, and retrofitting what remains, will save lives.

  • InfrastructureEngineers develop world’s longest “flat pack” arch bridge

    Civil Engineers at Queen’s University Belfast in collaboration with pre-cast concrete specialists Macrete Ireland have developed the world’s longest “flat pack” arch bridge. Based on the FlexiArch system, the bridge is unique in that it will be transported to site in flat-pack form but when lifted, will transform under gravity into an arch. A FlexiArch bridge requires little maintenance and should last 300 years, compared to the projected lifespan of up to 120 years that accompanies a conventional bridge.

  • InfrastructureUsing prefabrication in construction saves money

    Developers often choose prefabrication to save time on a project. Because the process of building a unit — like a bathroom or an exterior wall panel — off site can be more expensive up front, due largely to the cost of transporting the finished products to the job site, the overall financial benefits have not been well understood. A new study — one of the first to try and quantify the full costs and benefits of using prefabricated elements in a large-scale construction project – found that using prefabricated elements in the construction of the new Saint Joseph Hospital in Denver – opened on 13 December — cut seventy-two workdays off the construction schedule and resulted in $4.3 million in savings.

  • EarthquakesSeismic retrofitting of older buildings helps, but it has its limits

    Even before last Sunday’s magnitude-6 earthquake struck Napa, officials anticipated that such an event would damage many of Napa’s historic brick buildings. So years ago, brick structures were required to get seismic retrofitting — bolting brick walls to ceilings and floors to make them stronger. “We can’t keep every single brick in place in many of these older buildings without extraordinarily costly retrofits,” says a structural engineer. “We can reduce the damage in losses, but not eliminate them entirely in older buildings.”

  • Seismic protectionCold-formed steel construction withstands seismic challenges better than expected

    Engineering researchers have provided the building blocks necessary for enabling performance-based design for cold-formed steel buildings, structures that have shown in shake-test experiments at the State University of New York at Buffalo to withstand seismic loading much better than previously expected. Light, strong, and easy to construct cold-formed steel (CFS) buildings are repetitively framed with light steel members and conform to well-defined seismic design codes. Until this latest research, however, engineers and builders significantly underestimated the seismic strength of cold-formed steel structures.

  • Holy infrastructureErosion research could guide new preservation techniques

    Visitors to the Western Wall in Jerusalem can see that some of its stones are extremely eroded. This is good news for people placing prayer notes in the wall’s cracks and crevices, but presents a problem for engineers concerned about the structure’s stability. Research could guide development of new preservation techniques for weakened structures.

  • Nuclear powerHopes for quicker, cheaper ways to build nuclear power plants dim

    Promises of building a more cost effective U.S. nuclear industry continue to face setbacks as alternative energy sources like natural gas become cheaper for utilities, while new models for nuclear plants face cost overruns.Nuclear reactor developers sought to build new plants using prefabricated Lego-like blocks to save time and reduce labor costs, butanalysts consider the designs for the new nuclear reactors to be difficult or impossible to build.