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Fourth Power Law
The fourth power law (also known as the fourth power rule) states that the greater the axle load of a vehicle, the greater the stress on a road caused by the motor vehicle. The stress on the road increases in proportion to the fourth power of the axle load of the vehicle traveling on the road. This law was discovered in the course of a series of scientific experiments in the United States in the late 1950s and was decisive for the development of standard construction methods in road construction. Background At the beginning of the 1950s, the American Association of State Highway Officials (AASHO) dealt with the question of how the size of the axle load affects the service life of a road pavement. For this purpose, a test track was built in Ottawa, Illinois, which consisted of six loops, each with two lanes. The lanes were paved with both asphalt and concrete of varying thicknesses. In the two-year test, trucks with different axle loads then drove the roads almost continuously. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AASHO Road Test
The AASHO Road Test was a series of experiments carried out by the American Association of State Highway and Transportation Officials (AASHTO), to determine how traffic contributed to the deterioration of highway pavements. Methodology Officially, the Road Test was "...to study the performance of pavement structures of known thickness under moving loads of known magnitude and frequency." This study, carried out in the late 1950s in Ottawa, Illinois, is frequently quoted as a primary source of experimental data when vehicle wear to highways is considered, for the purposes of road design, vehicle taxation and costing. The road test consisted of six two-lane loops along the future alignment of Interstate 80. Each lane was subjected to repeated loading by a specific vehicle type and weight. The pavement structure within each loop was varied so that the interaction of vehicle loads and pavement structure could be investigated. Satellite studies were planned in other parts of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Association Of State Highway Officials
The American Association of State Highway and Transportation Officials (AASHTO) is a standards setting body which publishes specifications, test protocols, and guidelines that are used in highway design and construction throughout the United States. Despite its name, the association represents not only highways but air, rail, water, and public transportation as well. Although AASHTO sets transportation standards and policy for the United States as a whole, AASHTO is not an agency of the federal government; rather it is an organization of the states themselves. Policies of AASHTO are not federal laws or policies, but rather are ways to coordinate state laws and policies in the field of transportation. Purpose The American Association of State Highway Officials (AASHO) was founded on December 12, 1914. Its name was changed to American Association of State Highway and Transportation Officials on November 13, 1973. The name change reflects a broadened scope to cover all modes of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ottawa, Illinois
Ottawa is a city located at the confluence of the navigable Illinois River and Fox River in LaSalle County, Illinois, United States. The Illinois River is a conduit for river barges and connects Lake Michigan at Chicago, to the Mississippi River, and North America's 25,000 mile river system. The population estimate was 18,742, as of 2020. It is the county seat of LaSalle County and it is the principal city of the Ottawa, IL Micropolitan Statistical Area. History Ottawa occupies a place on the Illinois River that has long been one end of a portage trail between the Mississippi River and Lake Michigan. Here the river was reliably deep enough for canoes. The North Portage Trail connected the site over land and water to the Chicago River. Ottawa was the site of the first of the Lincoln–Douglas debates on August 21, 1858. During the Ottawa debate, Stephen A. Douglas, leader of the Democratic Party, openly accused Abraham Lincoln of forming a secret bipartisan group of Congressm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RWTH Aachen University
RWTH Aachen University (), also known as North Rhine-Westphalia Technical University of Aachen, Rhine-Westphalia Technical University of Aachen, Technical University of Aachen, University of Aachen, or ''Rheinisch-Westfälische Technische Hochschule Aachen'', is a German public research university located in Aachen, North Rhine-Westphalia, Germany. With more than 47,000 students enrolled in 144 study programs, it is the largest technical university in Germany. In 2018, the university was ranked 31st in the world university rankings in the field of engineering and technology, and 36th world-wide in the category of natural sciences.Daten & Fakten – RWTH AACHEN UNIVERSITY – Deutsch Rwth-aachen.de (12 December 2011). Retrieved on 2013-09-18. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonne
The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United States customary units), and the long ton ( British imperial units). It is equivalent to approximately 2204.6 pounds, 1.102 short tons, and 0.984 long tons. The official SI unit is the megagram (symbol: Mg), a less common way to express the same mass. Symbol and abbreviations The BIPM symbol for the tonne is t, adopted at the same time as the unit in 1879.Table 6 . BIPM. Retrieved on 2011-07-10. Its use is also official for the metric ton in the United States, having been adopted by the United States |
Pavement Engineering
Pavement engineering is a branch of civil engineering that uses engineering techniques to design and maintain flexible (asphalt) and rigid (concrete) pavements. This includes streets and highways and involves knowledge of soils, hydraulics, and material properties. Pavement engineering involves new construction as well as rehabilitation and maintenance of existing pavements. Maintenance often involves using engineering judgment to make maintenance repairs with the highest long-term benefit and lowest cost. The Pavement Condition Index (PCI) is an example of an engineering approach applied to existing pavements. Another example is the use of a falling weight deflectometer (FWD) to non-destructively test existing pavements. Calculation of pavement layer strengths can be performed from the resulting deflection data. The two methods - empirical or mechanistic is used to determine pavement layer thicknesses. The evaluation of existing road pavements is done based on 3 factors: * Func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pavement Performance Modeling
Pavement performance modeling or pavement deterioration modeling is the study of pavement deterioration throughout its life-cycle. The health of pavement is assessed using different performance indicators. Some of the most well-known performance indicators are Pavement Condition Index (PCI), International Roughness Index (IRI) and ''Present Serviceability Index'' (PSI), but sometimes a single distress such as rutting or the extent of crack is used. Among the most frequently used methods for pavement performance modeling are mechanistic models, mechanistic-empirical models, survival curves and Markov models. Recently, machine learning algorithms have been used for this purpose as well. Most studies on pavement performance modeling are based on IRI. History The study of pavement performance goes back to the first half of 20th century. The first efforts in pavement performance modeling were based on mechanistic models. Later researchers also developed empirical models, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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