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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.
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EarthquakesDisaster and recovery: The unexpected shall come to be expected
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.
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DamsResilient rivers respond quickly to dam removal
More than 1,000 dams have been removed across the United States because of safety concerns, sediment buildup, inefficiency, or having otherwise outlived usefulness. A paper published the other day finds that rivers are resilient and respond relatively quickly after a dam is removed. Studies show that most river channels stabilize within months or years, not decades, particularly when dams are removed rapidly.
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InfrastructureOver 61,000 U.S. bridges need structural repair
An analysis of the recently released 2014 U.S. Department of Transportation (U.S. DOT) National Bridge Inventory database finds good news and bad news when it comes to the most heavily traveled U.S. bridges. The good news is that there are over 2,000 fewer structurally deficient structures than there were in 2013. The bad news is that it means more than 61,000 structurally deficient bridges are still in need of significant repair. Cars, trucks, and school buses cross the nation’s 61,064 structurally compromised bridges 215 million times every day.
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InfrastructureBridge repair method cuts amount of time, money for bridge maintenance
According to American Society of Civil Engineers (ASCE) 2013 Report Card for America’s Infrastructure, one in nine of the U.S. 607,380 bridges is rated as structurally deficient, and $76 billion is needed to address the issue. The high cost is partly due to the fact that traditional repair methods are time consuming and labor intensive. Researchers, however, say that they have validated a new approach that could significantly reduce the amount of time and money needed to repair bridge components damaged by corrosion: Applying ultrahigh-performance concrete to the ends of corroded bridge beams could restore bearing capacity in a fraction of the time possible with traditional repair techniques.
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Coastal infrastructureU.K. coastal railways at increasing risk from climate change
Footage of a railway line suspended in mid-air and buffeted remorselessly by the storm that had caused the sea wall to collapse beneath it made for one of the defining images of 2014. Scenes such as those witnessed at Dawlish in Devon are set to become more frequent as a result of climate change, and the U.K. government and rail companies must face up to difficult funding decisions if rural areas currently served by coastal lines are to continue to be connected to the rail network. For railway builders in the mid-nineteenth century the coast was cheaper, flatter, and easier than using inland sites, one expert points out. “We wouldn’t have built these railway lines where they are if we had today’s knowledge.”
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InfrastructureDamage-sensing, self-repairing concrete
Skin is renewable and self-repairing — our first line of defense against the wear and tear of everyday life. If damaged, a myriad of repair processes spring into action to protect and heal the body. Clotting factors seal the break, a scab forms to protect the wound from infection, and healing agents begin to generate new tissue. Taking inspiration from this remarkable living healthcare package, researchers are asking whether damage sensing and repair can be engineered into a quite different material: concrete. Their aim is to produce a “material for life,” one with an in-built first-aid system that responds to all manner of physical and chemical damage by self-repairing, over and over again.
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Infrastructure protectionDrones to help assess post-disaster infrastructure damage
Drones can be used for a number of applications including civilian and military purposes. Monitoring and surveillance are two of the biggest uses for drones. Now, researchers are utilizing similar technology to develop an operational prototype that will use innovative remote sensing approaches and cameras mounted on low cost aircraft or unmanned drones to detect and map fine scale transportation infrastructure damage such as cracks, deformations, and shifts immediately following natural disasters such as earthquakes, floods and hurricanes. The researchers hope the technology becomes the new, Department of Transportation approach to monitoring infrastructure after natural disasters.
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Infrastructure protectionConcrete solutions to aging, structurally deficient bridges
According to the Pennsylvania Department of Transportation (PennDOT), the state leads the nation in the number of bridges classified as “structurally deficient.” This is probably not a surprise to most residents who have done any driving throughout the commonwealth. The state’s more than 25,000 state-owned bridges are aging — their average age is over fifty years — and in need of repair. Penn State civil engineering faculty are researching methods for enhancing the maintenance and durability of civil infrastructure — including anything made of concrete, from bridges to roads to buildings.
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Infrastructure protectionWireless sensors keep public infrastructure safe
European researchers have developed a wireless sensor system to monitor the safety of large infrastructure such as bridges – but also historic monuments. The new system will potentially save lives as the structure ages, and it will reducing construction cost of new infrastructure.
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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.
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InfrastructureMicro-capsules and bacteria used in self-healing concrete
Researchers are aiming to develop a novel self-healing concrete that uses an inbuilt immune system to close its own wounds and prevent deterioration. Self-healing concrete could vastly increase the life of concrete structures, and would remove the need for repairs, reducing the lifetime cost of a structure by up to 50 percent. Over seven per cent of the world’s CO2 emissions are caused by cement production, so reducing the amount required by extending the lifetime of structures and removing the need for repairs will have a significant environmental impact.
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BridgesResilience of California’s transportation infrastructure questioned
A significant number of bridges and elevated roadways lie above or close to active fault lines, and Californians often wonder how the state’s towering interchanges and freeway network would perform during a major earthquake.The California Department of Transportation (Caltrans) has spent over $13 billion in the last forty years to reinforce vulnerable bridges and interchanges. Caltrans officials note that during a major earthquake, freeways are likely to sustain significant damage, but engineers feel confident that freeways will not collapse.
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BridgesHere’s how to fix America’s crumbling bridges
There are about 600,000 bridges in the United States, and about one in four is classified as functionally obsolete or structurally deficient. This doesn’t mean they’re in danger of imminent collapse; they may be simply too narrow or built for lighter traffic than today’s standards. Bridges that can’t support heavy trucks have weight restrictions posted. There are plenty of repairs that need to be done. With government funding for infrastructure projects being so tight, an alternative has arisen in what are called public-private partnerships, often abbreviated PPP or P3. In this arrangement, private investors assume the responsibility for financing and building a bridge or highway, and the investors are granted the right to collect tolls for what may be decades. The investors naturally believe they will realize a good return on their investment, even after they pay the public partner a sizable sum upfront for the concession. This upfront payment can be in the billions of dollars, which can be very tempting for a state or municipality struggling to balance its budget.
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InfrastructureUpgrading infrastructure could reduce future flood damage
From 1980 to 2007, about 90 percent of all global disasters were caused by flooding either by rain, tsunami, hurricane, or some other natural event. At the same time, the American Society of Civil Engineer’s 2013 Report Card for America’s Infrastructure gave the country a dismal D+. The group said $3.6 trillion was needed by 2020 to address the most serious problems. In Colorado, the report card says, 70 percent of major roads are poor or mediocre and 566 bridges are structurally deficient. A new study argues that the severe flooding that devastated a wide swath of Colorado last year might have been less destructive if the bridges, roads, and other infrastructure had been upgraded or modernized.
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