15-11-2012, 01:31 PM
GRAVITY DAM
GRAVITY DAM.pptx (Size: 2.53 MB / Downloads: 38)
INTODUCTION:
Gravity dams are dams which resist the horizontal thrust of the water entirely by their own weight. They use their weight to hold back the water in the reservoir can be made of earth or rock fill or concrete.
Basically, gravity dams are solid concrete structures that maintain their stability against design loads from the geometric shape and the mass and strength of the concrete.
Construction Materials :
The design of concrete dams involves consideration of various construction materials during the investigations phase. An assessment is required on the availability and suitability of the materials needed to manufacture concrete qualities meeting the structural and durability requirements, and of adequate quantities for the volume of concrete in the dam and appurtenant structures. Construction materials include fine and coarse aggregates, cement, water for washing aggregates, mixing, curing of concrete, and chemical admixtures.
Site Selection
During the feasibility studies, the preliminary site selection will be dependent on the project purposes within the Corps’ jurisdiction.
Purposes applicable to dam construction include navigation, flood dam age reduction, hydroelectric power generation, fish and wildlife enhancement, water quality, water supply, and recreation.
The feasibility study will establish the most suitable and economical location and type of structure.
Investigations will be performed on hydrology and meteorology, relocations, foundation and site geology, construction materials, appurtenant features, environmental considerations, and diversion methods.
Construction of Gravity dam
RIVER DIVERSION
Regardless of the type of dam, whether concrete or embankment types, it is necessary to de-water the site for final geological inspection, for foundation improvement and for the construction of the first stage of the dam. In order to carry out the above works the river has to be diverted temporarily.
The magnitude, method and cost of river diversion
will depend upon the cross- section of the valley, the bed material in the river, the type
of dam