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Rural California country faces levee dilemma
About 400 homes and rich farmland in District-10 of Marysville, California risk being flooded should the levees protecting the area fail. The levees, stretching over twenty-eight miles, were built in the early 1900s. The area’s low population may be one reason why county officials have neglected making improvements to the levees in District-10. Local opponents of investment in shoring up the levees are worried that if the levees are improved and the area made safer, “It would open the door for more agribusiness type things, but it would also open the door for more subdivisions,” in the words of one of them.
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A state of disrepair: Thousands of U.S. aging bridges risk collapse
Of the 607,380 bridges listed in the recent U.S. National Bridge Inventory, 65,605 bridges are classified as “structurally deficient” and 20,808 as “fracture critical,” with 7,795 of those bridges designated as both structurally deficient and fracture critical. Experts say this indicates significant disrepair and a risk of collapse. These 7,795 structurally deficient, fracture critical bridges carry more than twenty-nine million drivers a day.
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Bay Bridge repairs expensive, slow
California’s 8-mile San Francisco-Oakland Bay Bridge was designed and built in the 1930s in about 5.5 years at a cost of $78 million, well under budget and ahead of schedule. Presently, the 2-mile eastern span of the bridge needs to be replaced, and it has taken the state five years just to design the replacement. Construction is taking about three times the expected time, and the $6.4 billion budget is almost five times the estimate provided by engineers.
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Ultrathin radios enable flexible structural-health monitoring system
Currently, engineers can use single-point sensors or fiber optic strips to detect structural problems, but the devices can collect data over relatively small spaces. The problem is that many failures develop over large areas and cannot be detect that at an early stage. The 2007 collapse of a highway bridge in Minneapolis, for example, developed over a gusset plate with an area of several square meters, far too large for current monitoring systems to practically survey. Researchers have developed ultrathin radios which can be embedded directly on plastic sheets, which can be applied to walls and other structures. The innovation could be used for new devices ranging from an invisible communications system inside buildings to sophisticated, flexible structural health monitoring system for use on bridges, buildings, roads, pipelines, and other structures.
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Sandy shows need for more effective preparedness, resiliency standards
The rebuilding efforts following the devastation wreaked by Superstorm Sandy have triggered a discussion over preparedness and resiliency in America’s commercial and residential buildings.Some experts callfor a presidential appointment of a building resilience “’czar”’ with authority to coordinate and seek synergies between public and private sector initiatives.
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Feds give upstate New York counties $5 million money to repair roads, bridges
The Federal Highway Administration (FHA) has approved $5 million in emergency funding to help fifteen upstate New York counties make repairs to their roads and bridges damaged in a flood late last month.
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Motivating businesses to adopt building resiliency standards
Increased resilience for buildings in the face of hurricanes, earthquakes, terrorism, or cyberattacks has been a major national security focus over the past decade. Such resilient buildings not only would be less susceptible to damage and work interruption but could become community gathering places in a general crisis. It will not be easy, however, to secure voluntary adoption of resiliency standards by industry and builders without adequate justification.
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UMaine student develops affordable option for shoring up Maine’s aging bridges
The State of Maine Department of Transportation is responsible for 2,772, or 70 percent, of the bridges in the state. A 2007 report found that of those bridges, 205 are more than 80 years old, 244 were considered in poor condition, and 213 were found to be structurally deficient. Additionally, 288 bridges were at risk of closure or weight restrictions between 2007 and 2017. Replacing all these bridges would be too costly. Researchers developed software designed specifically to assess the load rating of flat-slab bridges to determine which bridges can be repaired instead of replaced. For the bridges that can last a few more years with reinforcing instead of replacing, the researchers engineered a retrofitting system which could be applied to increase the bridge’s strength and weight limits.
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Crawling robot examines, evaluates condition of load-bearing cables
Severe weather events inflict damage and destruction. The condition of infrastructure and its components may contribute to the overall damage: weak components and damaged elements make infrastructure less likely to withstand the stress of a storm. Researchers have developed a crawling robot capable of examining and evaluating the condition of load-bearing cables, such as those found in bridges, elevators, and cable cars.
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Earthquake-proofing precast buildings
Precast or ready-made building structures offer a number of advantages when compared to more traditional construction techniques in terms of time and cost savings. The vulnerability of joints and connections between assembled precast elements, however, is widely recognized as a potential safety issue, especially in earthquake-prone areas. An EU-funded project has set out to develop new procedures and guidelines for designing precast structure joints and connections that can stand up to seismic forces.
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U California, Berkeley students win National Student Steel Bridge Competition
The weekend of 31 May residents of Washington State watched as engineers began erecting a temporary steel bridge over the Skagit River, to replace the 160-foot span of a 4-lane bridge that had collapsed a week earlier, after being struck by an over-height truck. Just sixty miles away, on the campus of the University of Washington in Seattle, 620 civil engineering students erected their own temporary steel bridges in a competition to demonstrate their engineering skills. For the second consecutive year and for the second time in the past seven years, a team of students from the University of California, Berkeley captured the title as champions of the ASCE/AISC National Student Steel Bridge Competition (NSSBC).
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Thousands of U.S. bridges in “fracture critical” condition
There are currently 66,749 structurally deficient bridges and 84,748 functionally obsolete bridges in the United States – about a quarter of the nation’s 607,000 bridges. With declining federal funds for bridge repair, the burden of maintenance has shifted to states, which spent $28.5 billion last year on bridge work – up from $12.3 billion in 1998.
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Ash from olive residue biomass leads to more effective, cheaper concrete
Researchers have produced self-compacting concrete with ash from boiler combustion of olive pruning residue pellets. The plasticity and cohesion of this type of concrete mean no compaction is needed when used in construction and, moreover, it has other advantages with respect to conventional concrete.
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Helping bridges withstand natural disaster
Structural control systems have the potential to help our civil infrastructure, such as bridges, roads, and buildings, withstand natural disasters such as earthquakes or storms. Traditional control systems based on sensors connected by wired networks, however, are costly, labor-intensive, and tend to break during disasters, when they are needed most.Wireless networks that are easier, cheaper, and more resilient to structural damage.
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Larger fire-fighting crews save lives, limit damage in high-rise fires
Between 2005 and 2009 there were, on average, 15,700 high-rise structure fires annually in the United States. Average annual losses totaled 53 civilian deaths, 546 civilian injuries, and $235 million in property damage. When responding to fires in high-rise buildings, firefighting crews of five or six members — instead of three or four — are significantly faster in putting out fires and completing search-and-rescue operations, concludes a major new study.
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