ICOLD Committee on Seismic Aspects of Dam Design dams. For a m high CFRD constructed of most rock types, acceptable performance can be predicted . The NN2 Concrete Face Rockfill Dam (CFRD) has the lowest foundation level at masl and the crest elevation at masl, which corresponds to the. number of rockfill dams with reinforced concrete screens all over the world. .. Zeping X. “Three dimensional stress and deformation analysis of Wuluwati CFRD .
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A dam is a barrier that stops or restricts the flow of water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigationhuman consumptionindustrial useaquacultureand navigability.
Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect water or for storage of water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees also known as dikes are used to manage or prevent water flow into specific land regions. The word dam can be traced back to Middle English and before that, from Middle Dutchas seen in the names of many old cities.
However, there is one village, Obdamthat is already mentioned in The word seems to be related to the Greek word taphosmeaning “grave” or “grave hill”. The names of more than 40 places with minor changes from the Middle Dutch era — CE such as Amsterdam founded as ‘Amstelredam’ in the late 12th century and Rotterdamalso bear testimony to the use of the word in Middle Dutch at that time.
Early dam building took place in Mesopotamia and the Middle East. Dams were used to control the water level, for Mesopotamia’s weather affected the Tigris and Euphrates rivers.
The structure is dated to BC. The structure was built around  or BC  as a diversion dam for flood control, but was destroyed by heavy rain during construction or shortly afterwards. Two dams called Ha-Uar running east-west were built to retain water during the annual flood and then release it to surrounding lands. By the mid-late third millennium BC, an intricate water-management system within Dholavira in modern-day India was dzm. The system included 16 reservoirs, dams and various channels for collecting water and storing it.
One of the engineering wonders of the ancient world was the Great Dam of Marib in Yemen. It is thought to be from the time of the Hittite empire between the 15th and 13th century Cvrd.
The basic structure dates dxm the 2nd century AD  and cfr considered one of the oldest water-diversion or water-regulator structures in the world which is still in use. Du Jiang Yan is the oldest surviving irrigation system in China that included a dam that directed waterflow.
It was finished in BC. Roman dam construction was characterized by “the Romans’ ability to plan and organize engineering construction on a grand scale.
Roman engineers made routine use of ancient standard designs like embankment dams and masonry gravity dams. These include arch-gravity dams arch dams buttress dams  and multiple arch buttress dams all of which were known and employed by the 2nd century AD see List of Roman dams. Roman workforces also were the first to build dam bridges, such as the Bridge of Valerian in Iran.
In Iranbridge dams such as the Band-e Kaisar were used to provide hydropower through water wheelswhich often powered water-raising mechanisms. One of the first was the Roman-built dam bridge in Dezful which could raise water 50 cubits in height for the water supply to all houses in the town.
Also diversion dams were known. The first was built at Shustar on the River KarunIran, and many of these were later built in other parts of the Islamic world. In the Netherlandsa low-lying country, dams were often applied to block rivers in order to regulate the water level and to prevent the sea from entering the marsh lands. Such dams often marked the beginning of a town or city because it was easy to cross the river at such a place, and often gave rise to the respective place’s names in Dutch.
For instance the Dutch capital Amsterdam old name Amstelredam started with a dam through the river Amstel in the late 12th century, and Rotterdam started with a dam through the river Rottea minor tributary of the Nieuwe Maas.
The central square of Amsterdam, covering the original place of the year-old dam, still carries the name Dam Square or simply the Dam. The Romans were the first to build arch damswhere the reaction forces from the abutment stabilizes the structure from the external hydrostatic pressurebut it was only in the 19th century that the engineering skills and construction materials available were capable of building the first large-scale arch dams.
Three pioneering arch dams were built around the British Empire in the early 19th century. Henry Russel of the Royal Engineers oversaw the construction of the Mir Alam dam in to supply water to the city of Hyderabad it is still in use today. In the s and 30s, Lieutenant-Colonel John By supervised the construction of the Rideau Canal in Canada near modern-day Ottawa and built a series of curved masonry dams as part of the waterway system.
In particular, the Jones Falls Dambuilt by John Redpathwas completed in as the largest dam in North America and an engineering marvel. In order to keep the water in control during construction, two sluicesartificial channels for conducting water, were kept open in the dam.
The first was near the base of the dam on its east side. To make the switch from the lower to upper sluice, the outlet of Sand Lake was blocked off. Hunts Creek near the city of ParramattaAustraliawas dammed in the s, to cater for the demand for water from the growing population of the city.
The masonry arch dam wall was designed by Lieutenant Percy Simpson who was influenced by the advances in dam engineering techniques made by the Royal Engineers in India. The first such dam was opened two years earlier in France. After royal approval was granted inthe dam was constructed over the following decade.
Its construction was carried out on the basis of the mathematical results of scientific stress analysis. The miles dam near WarwickAustralia, was possibly the world’s first concrete arch dam.
In the latter half of the nineteenth century, significant advances in the scientific theory of masonry dam design were made. This transformed dam design from an art based on empirical methodology to a profession based on a rigorously applied scientific theoretical framework.
This new emphasis was centered around the engineering faculties of universities in France and in the United Kingdom. Rankine theory provided a good understanding of the principles behind dam design. Augustin Tortene de Sazilly explained the mechanics of vertically faced masonry gravity dams, and Zola’s dam was the first to be built on the basis of these principles.
The era of large dams was initiated with the construction of the Aswan Low Dam in Egypt ina gravity masonry buttress dam on the Nile River. Following their invasion and occupation of Egyptthe British began construction in The Hoover Dam is a massive concrete arch-gravity damconstructed in the Black Canyon of the Colorado Riveron the border between the US states of Arizona and Nevada between and during the Great Depression.
InCongress authorized the project to build a dam that would control floods, provide irrigation water and produce hydroelectric power.
The winning bid to build the dam was submitted by a consortium called Six Companies, Inc.
Dam – Wikipedia
Such a large concrete structure had never been built before, and some of the techniques were unproven. The torrid summer weather and the lack of facilities near the site also presented difficulties.
Dqm, Six Companies turned over the dam to the federal government on 1 Marchmore cfrf two years ahead of schedule.
Dams can be formed by human agency, natural causes, or even by the intervention dwm wildlife such as beavers. Man-made dams are typically classified according to their size heightintended purpose or structure. Based on structure and material used, dams are classified as easily created without materials, arch-gravity damsembankment dams or masonry damswith several subtypes.
In the arch dam, stability is obtained by a combination of arch and gravity action.
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If the upstream face is vertical the entire weight of the dam must be carried to the foundation by gravity, while the distribution of the normal hydrostatic pressure between vertical cantilever and arch action will depend upon the stiffness of the dam in a vertical and horizontal direction. When the upstream face is vfrd the distribution is more complicated. The normal component of the weight of the arch ring may be taken by the arch action, while the normal hydrostatic pressure will be distributed as described damm.
For this type of dam, firm reliable supports at the abutments either buttress or canyon side wall are more important. The most desirable place for an arch dam is a narrow canyon with steep side walls composed of dxm rock.
Two types of single-arch dams are ddam use, namely the constant-angle and the constant-radius dam. The constant-radius type employs the same face radius at all elevations of the dam, which means that as the channel grows da towards the bottom of the dam the central angle subtended by the face of the dam becomes smaller.
Jones Falls Damin Canada, is a constant radius dam. In a constant-angle daam, also known cfrf a variable radius dam, this subtended angle is kept a constant and the variation in distance between the abutments at various levels are taken care of by varying the radii. Constant-radius dams are much less common than constant-angle dams.
Parker Dam on the Colorado River is a constant-angle arch dam. A similar type is the double-curvature or thin-shell dam. This method of construction minimizes the amount of concrete necessary for construction but transmits large loads to the foundation and abutments.
The appearance is similar to a single-arch dam but with a distinct vertical curvature to it as well lending it the vague appearance of a concave lens as viewed from downstream. The multiple-arch dam does not require as many buttresses as the hollow gravity type, but requires good rock foundation because the buttress loads are heavy.
In a cam dam, the force that holds the dam in place against the push from the water is Earth’s gravity pulling down on the mass of the dam. The dam’s weight counteracts that force, tending to rotate the dam the other way about its toe. The designer ensures that the dam is heavy enough that the dam’s weight wins that contest. In engineering terms, that is true whenever the resultant of the forces of gravity acting on the dam and water pressure on the dam acts in a line that passes upstream of the toe of the dam.
Furthermore, the designer tries to shape the dam so if one were to consider the part of dam above any particular height to be a whole dam itself, that dam also would be held in place by gravity. The designer does this because it is usually more practical to make a dam of material essentially just piled up than to make the material stick together against vertical tension.
Note that the shape that prevents tension in the upstream face also eliminates a balancing compression stress in the downstream face, providing additional economy. For adm type of dam, it is essential to have an impervious foundation with high bearing strength. When situated on a suitable site, a gravity dam can prove to be a better alternative to other types of dams. When built on a carefully studied foundation, the gravity dam probably represents the best developed example of dam building.
Since the fear of flood is a strong motivator in many regions, gravity dams are being built in some instances where an arch dam would have been more economical. Gravity dams are classified as “solid” or “hollow” and are generally made of either concrete or masonry. The solid form is the more widely used of the two, though the hollow dam is frequently more economical to construct. A gravity dam can be combined with an arch dam into an arch-gravity dam for areas with massive amounts of water flow but less material available for a purely gravity dam.
The inward compression of the dam by the water reduces the lateral horizontal force acting on the dam. Thus, the gravitation force required by the dam is lessened, i.
This enables thinner dams and saves resources. A barrage dam is a special kind of dam which consists of a line of large gates that can be opened or closed to control the amount of water passing the dam. The gates are set between flanking piers which are responsible for supporting the water load, and are often used to control and stabilize water flow for irrigation systems.
cfgd Barrages that are built at the mouths of rivers or lagoons to prevent tidal incursions or utilize the tidal flow for tidal power are known as tidal barrages.