Gravity Dams
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Gravity Dams
A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by using only the weight of the material and its resistance against the foundation. Gravity dams are designed so that each section of the dam is stable and independent of any other dam section. Characteristics Gravity dams generally require stiff rock foundations of high bearing strength (slightly weathered to fresh), although in rare cases, they have been built on soil. Stability of the dam primarily arises from the range of normal force angles viably generated by the foundation. Also, the stiff nature of a gravity dam structure endures differential foundation settlement poorly, as it can crack the dam structure. The main advantage to gravity dams over embankments is the scour-resistance of concrete, which protects against damage from minor over-topping flows. Unexpected large over-topping flows are still a problem, as they can scour dam foundations. A disadvantage of gravit ...
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Roller-compacted Concrete
Roller-compacted concrete (RCC) or rolled concrete (rollcrete) is a special blend of concrete that has essentially the same ingredients as conventional concrete but in different ratios, and increasingly with partial substitution of fly ash for portland cement. The partial substitution of fly ash for Portland Cement is an important aspect of RCC dam construction because the heat generated by fly ash hydration is significantly less than the heat generated by portland cement hydration. This in turn reduces the thermal loads on the concrete and reduces the potential for thermal cracking to occur. RCC is a mix of cement/fly ash, water, sand, aggregate and common additives, but contains much less water. The produced mix is drier and essentially has no slump. RCC is placed in a manner similar to road paving; the material is delivered by dump trucks or conveyors, spread by small bulldozers or specially modified asphalt pavers, and then compacted by vibratory rollers. In dam construc ...
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Earthquake
An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume. In its most general sense, the word ''earthquake'' is used to describe any seismic event that generates seismic waves. Earthquakes can occur naturally or be induced by human activities, such as mining, fracking, and nuclear weapons testing. The initial point of rupture is called the hypocenter or focus, while the ground level directly above it is the ...
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Arch Action
An arch is a curved vertical structure spanning an open space underneath it. Arches may support the load above them, or they may perform a purely decorative role. As a decorative element, the arch dates back to the 4th millennium BC, but structural load-bearing arches became popular only after their adoption by the Ancient Romans in the 4th century BC. Arch-like structures can be horizontal, like an arch dam that withstands the horizontal hydrostatic pressure load. Arches are usually used as supports for many types of vaults, with the barrel vault in particular being a continuous arch. Extensive use of arches and vaults characterizes an arcuated construction, as opposed to the trabeated system, where, like in the architectures of ancient Greece, China, and Japan (as well as the modern steel-framed technique), posts and beams dominate. Arches had several advantages over the lintel, especially in the masonry construction: with the same amount of material it can have larger ...
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Shasta Dam
Shasta Dam (called Kennett Dam before its construction) is a concrete arch-gravity dam across the Sacramento River in Northern California in the United States. At high, it is the eighth-tallest dam in the United States. Located at the north end of the Sacramento Valley, Shasta Dam creates Shasta Lake for long-term water storage, flood control, hydroelectricity and protection against the intrusion of saline water. The largest reservoir in the state, Shasta Lake can hold about . Envisioned as early as 1919 as an effort to conserve, control, store, and distribute water to the Central Valley, California's main agricultural region, Shasta was first authorized in the 1930s as a state undertaking. However, bonds did not sell due to the onset of the Great Depression and Shasta was transferred to the federal Bureau of Reclamation as a public works project. Construction started in earnest in 1937 under the supervision of Chief Engineer Frank Crowe. During its building, the dam provid ...
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Braddock Locks & Dam
Braddock Locks & Dam (previously named Monongahela Locks and Dam No. 2) is one of nine navigational structures on the Monongahela River between Pittsburgh, Pennsylvania and Fairmont, West Virginia. Built and maintained by the U.S. Army Corps of Engineers, the gated dam and the lock form an upstream pool that is for , stretching to Elizabeth, Pennsylvania. Description Braddock Locks and Dam consists of the locks located on the right bank and the newly gated dam, that replaced the nearly 100-year-old fixed-crest dam. The older structure in turn had replaced a lock and dam facility opened in 1841 at Port Perry, slightly upriver from Braddock. Locks Built in 1953, the locks consist of two side-by-side chambers. The land chamber is wide by long and the river chamber is wide by long. Dam Construction of new Braddock Dam, started in 1999, was completed in May 2004 using innovative in-the-wet construction techniques. Two prefabricated hollow concrete segments were constructed at ...
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Cheesman Dam
Cheesman Dam is a masonry curved gravity dam on the South Platte River located in Colorado. It was the tallest of its type in the world when completed in 1905. The primary purpose of the dam is water supply and it was named for Colorado businessman, Walter Cheesman. In 1973 it was designated a Historic Civil Engineering Landmark. Denver Water purchased the reservoir and related facilities in 1918. History The location for the new dam was explored by chief engineer C.P. Allen on during a fishing trip on September 23, 1893. The first stage was to build a diversion tunnel in 1898, which after the completion of the dam would become the outlet. The plans called for an embankment dam faced with concrete and metal some 200 feet tall, which began to rise in 1899. This was not to be as after one year of work, on the morning of May 3, 1900, the river began to rise after a heavy rainstorm added to the already high spring river flow. The water filled the outlet pipe and then overtoppe ...
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Pathfinder Dam
Pathfinder Dam is a masonry dam, located on the North Platte River, approximately southwest of Casper, Wyoming. It was constructed from 1905 to 1909 as part of the North Platte Project and has been modified several times since then. It is included on the National Register of Historic Places. Construction of the dam created Pathfinder Reservoir which provides water storage for of irrigation in Wyoming and Nebraska. The dam is named for General John Charles Fremont, who had explored the area in 1842 and was nicknamed the "Pathfinder of the West." Description Pathfinder Dam is composed of granite blocks, quarried from the same stone that forms the river's canyon. With Buffalo Bill Dam, its contemporary, Pathfinder Dam was intended to irrigate semi-arid lands in Wyoming. Buffalo Bill Dam is of concrete construction, owing to its location within from the railroad, while Pathfinder Dam is about from the nearest railroad. Freight took at least three days to cover the distance, ...
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Aswan Low Dam
The Aswan Low Dam or Old Aswan Dam is a gravity masonry buttress dam on the Nile River in Aswan, Egypt. The dam was built by the British at the former first cataract of the Nile, and is located about 1000 km up-river and 690 km (direct distance) south-southeast of Cairo. When initially constructed between 1899 and 1902, nothing of its scale had ever been attempted; on completion, it was the largest masonry dam in the world. The dam was designed to provide storage of annual floodwater and augment dry season flows to support greater irrigation development and population growth in the lower Nile. The dam, originally limited in height by conservation concerns, worked as designed, but provided inadequate storage capacity for planned development and was raised twice: between 1907 and 1912 and again between 1929 and 1933. These heightenings still did not meet irrigation demands and in 1946 it was nearly over-topped in an effort to maximize pool elevation. This led to the invest ...
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Masonry Dam
Masonry dams are dams made out of masonrymainly stone and brick, sometimes joined with mortar. They are either the gravity or the arch-gravity type. The largest masonry dam in the World is Nagarjuna Sagar Dam, Andhra Pradesh and Telangana, in India. Visual examples Image:Roosevelt Dam original masonry.jpg, The original Theodore Roosevelt Dam in Arizona Image:New Croton Dam from below.jpg, New Croton Dam in New York Image:Artouste-dam1.JPG, The Artouste Dam in France Image:NagarjunaSagarDam.JPG, The Nagarjuna Sagar Dam in India is the largest masonry dam in the world See also * Arch-gravity dam *Causeway * Dam * Gravity dam *Retaining wall Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to ... * Wicket dam References {{Reflist 01 Dams by type Masonry buildings and str ...
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Upper Stillwater Dam
Upper may refer to: * Shoe upper or ''vamp'', the part of a shoe on the top of the foot * Stimulant, drugs which induce temporary improvements in either mental or physical function or both * ''Upper'', the original film title for the 2013 found footage film ''The Upper Footage'' * Dmitri Upper (born 1978), Kazakhstani ice hockey player See also * Uppers (video game) is a Japanese video game developer and publisher, and anime producer. The company was founded in 1997 but formed in its current state in October 2011 by the merger of the original Marvelous Entertainment with AQ Interactive, and Liveware. Hi ...
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Willow Creek Dam (Oregon)
Willow Creek Dam is a dam in Morrow County of the U.S. state of Oregon, located just east of Heppner's city limits. It was the first major dam in the United States constructed of roller-compacted concrete. The dam's drainage basin is of arid rolling hills in the lower basin but with headwaters in the northern Umatilla National Forest. The dam's original purpose was primarily to store water for flood control, but also to serve recreation, fish and wildlife, and irrigation uses. The dam impounds Willow Creek to create Willow Creek Lake. The lake level can be a maximum of elevation and a minimum of for a total usable storage capacity of . History A major flood killed approximately one quarter of Heppner's population in June 1903—about 250 people. The flooding creek flow was as a result of a flash flood caused by thunderstorms, known as the Heppner Flood of 1903. A flood control study was completed in 1962 at a total cost of $219. In 1965, a flood control project was ...
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