|
F-shape Barrier
The F-shape barrier is a concrete crash barrier, originally designed to divide lanes of traffic on a highway. It is a modification of the widely used Jersey barrier design, and is generally considered safer. A parametric study, one that systematically varies the parameters, was done through computer simulations of barrier profiles labeled A through F. The result showed that the one labeled F performed better than even the shape of the Jersey barrier. A series of full-scale crash tests later confirmed these computer-based results. What is known today as the F-shape barrier takes its name from these tests and not from any part of the shape of the barrier, unlike, for example, T-walls. In spite of these tests, the F-shape barrier has not supplanted the Jersey-shape. The Jersey-shape barrier was already in wide use, and it also met the crash-test criteria. The states' contractors already had a significant investment in the Jersey-shape casting forms and it would cost them money to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminum combined. Globally, the ready-mix concrete industry, the largest segment of the concrete market, is projected to exceed $600 billion in revenue by 2025. This widespread use results in a number of environmental impacts. Most notably, the production process for cement produces large volumes of greenhouse gas emissions, leading to net 8% of global emissions. Other environmental concerns include widespread illegal sand mining, impacts on the surrounding environment such as increased surface runoff or urban heat island effect, and potential public health implications from toxic ingredients. Significant research and development is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crash Barrier
Traffic barriers (sometimes called Armco barriers,AK Steel (formerly Armco) genericized trademark also known in North America as guardrails or guard rails and in Britain as crash barriers) keep vehicles within their roadway and prevent them from colliding with dangerous obstacles such as boulders, sign supports, trees, bridge abutments, buildings, walls, and large storm drains, or from traversing steep (non-recoverable) slopes or entering deep water. They are also installed within medians of divided highways to prevent errant vehicles from entering the opposing carriageway of traffic and help to reduce head-on collisions. Some of these barriers, designed to be struck from either side, are called median barriers. Traffic barriers can also be used to protect vulnerable areas like school yards, pedestrian zones, and fuel tanks from errant vehicles. While barriers are normally designed to minimize injury to vehicle occupants, injuries do occur in collisions with traffic barriers. They ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Highway
A highway is any public or private road or other public way on land. It is used for major roads, but also includes other public roads and public tracks. In some areas of the United States, it is used as an equivalent term to controlled-access highway, or a translation for ''autobahn'', '' autoroute'', etc. According to Merriam Webster, the use of the term predates the 12th century. According to Etymonline, "high" is in the sense of "main". In North American and Australian English, major roads such as controlled-access highways or arterial roads are often state highways (Canada: provincial highways). Other roads may be designated "county highways" in the US and Ontario. These classifications refer to the level of government (state, provincial, county) that maintains the roadway. In British English, "highway" is primarily a legal term. Everyday use normally implies roads, while the legal use covers any route or path with a public right of access, including footpaths etc. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jersey Barrier
A Jersey barrier, Jersey wall, or Jersey bump is a modular concrete or plastic barrier employed to separate lanes of traffic. It is designed to minimize vehicle damage in cases of incidental contact while still preventing vehicle crossovers resulting in a likely head-on collision. Jersey barriers are also used to reroute traffic and protect pedestrians and workers during highway construction. They are named after the U.S. state of New Jersey which first started using the barriers as separators between lanes of a highway in the 1950s. The barriers are also known as a K-rail, a term stipulated in the California Department of Transportation specification for temporary concrete traffic barriers which first started using concrete median barriers in the mid-1940s. Over time, different variants were created. Taller variants, such as the Ontario Tall Wall, proved more effective at stopping vehicles and had the added advantage of blocking most oncoming headlights. More modular variant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parametric Statistics
Parametric statistics is a branch of statistics which assumes that sample data comes from a population that can be adequately modeled by a probability distribution that has a fixed set of Statistical parameter, parameters. Conversely a non-parametric model does not assume an explicit (finite-parametric) mathematical form for the distribution when modeling the data. However, it may make some assumptions about that distribution, such as continuity or symmetry. Most well-known statistical methods are parametric. Regarding nonparametric (and semiparametric) models, David Cox (statistician), Sir David Cox has said, "These typically involve fewer assumptions of structure and distributional form but usually contain strong assumptions about independencies". Example The normal distribution, normal family of distributions all have the same general shape and are ''parameterized'' by mean and standard deviation. That means that if the mean and standard deviation are known and if the distribu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-Wall
A Bremer wall, or T-wall, is a portable, steel-reinforced concrete blast wall of the type used for blast protection throughout Iraq and Afghanistan. The Bremer barrier resembles the smaller Jersey barrier, which has been used widely for vehicle traffic control on coalition military bases in Iraq and Afghanistan. To indicate that the Bremer barrier is similar but larger, the , intermediate-sized Bremer barriers are usually referred to as Texas barriers, but not to be confused with the Texas constant-slope barrier. Similarly, the largest barriers, which stand around , are called Alaska barriers. Unlike the Jersey barrier, which has sloped sides at the base, some Texas and Alaska barriers have a rectangular ledge base, usable as a bench for sitting or resting and approximately knee-high for a typical adult. Etymology These T-shaped walls were originally developed by the Israelis in the Israeli West Bank barrier. The term "T-wall" has been used commonly, due to the wall's cross- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete Step Barrier
A concrete step barrier is a safety barrier used on the central reservation of motorways and dual carriageways as an alternative to the standard steel crash barrier. United Kingdom With effect from January 2005 and based primarily on safety grounds, the UK National Highways policy is that all new motorway schemes are to use high-containment concrete barriers in the central reserve. All existing motorways will introduce concrete barriers into the central reserve as part of ongoing upgrades and through replacement when these systems have reached the end of their useful life. This change of policy applies only to barriers in the central reserve of high-speed roads and not to verge-side barriers. Other routes will continue to use steel barriers. Government policy ensures that all future crash barriers in the UK will be made of concrete unless there are overriding circumstances. Ireland The usage of the concrete step barrier has become widespread in Ireland. As of 2017, of motorw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constant-slope Barrier
A constant slope barrier is a traffic barrier made of reinforced concrete and designed with a single slope that is used to separate lanes of vehicular traffic. Its advantages compared to more complex shapes arise because its performance is not as affected by changes in the height of the roadbed during repaving. The Texas Constant-Slope Barrier is high and has a constant slope face that makes an angle of 10.8 degrees with respect to the vertical. California has developed a constant slope barrier with an angle of 9.1 degrees with respect to the vertical. The Texas Constant-Slope barrier has performed similarly in crash tests to the Jersey barrier. The California design compared similarly to the F-Shape barrier The F-shape barrier is a concrete crash barrier, originally designed to divide lanes of traffic on a highway. It is a modification of the widely used Jersey barrier design, and is generally considered safer. A parametric study, one that system ... in crash tests. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protective Barriers
A separation barrier or separation wall is a barrier, wall or fence, constructed to limit the movement of people across a certain line or border, or to separate peoples or cultures. A separation barrier that runs along an internationally recognized border is known as a border barrier. David Henley opines in ''The Guardian'' that separation barriers are being built at a record-rate around the world along borders and do not only surround dictatorships or pariah states. In 2014, The ''Washington Post'' listed notable 14 separation walls as of 2011, indicating that the total concurrent number of walls and barriers which separate countries and territories is 45. The term "separation barrier" has been applied to structures erected in Belfast, Homs, the West Bank, São Paulo, Cyprus, and along the Greece-Turkey border and the Mexico-United States border. In 2016, Julia Sonnevend listed in her book ''Stories Without Borders: The Berlin Wall and the Making of a Global Iconic Event'' th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Highway")
