Contents

1.1 TYPES OF 1.1.1 Embankment 1.1.2 Concrete Arch and Dome Dams 13 1.1.3 Concrete Gravity and Gravity-Arch Dams 14 1.1.4 Concrete Slab and Buttress Dams 16 1.2 APPURTENANT FEATURES OF DAMS 16 1.3 SAFETY OF DAMS AND RESERVOIRS 18 1.4 HOW DAMS ARE 1.5 FAMOUS DAMS OF THE WORLD 21 1.6 POWER GENERATOR, FLOOD CONTROL AND IRRIGATION DAMS 1.6.1 Power Generator 1.6.2 Flood Control 1.6.3 Irrigation 1.7 INSTRUMENTATIONS AND SURVEILLANCE OF DAMS . 28 1.8 ECOLOGICAL ENVIRONMENTAL CONSIDERATION OF DAM...

Development of the Modern Dams

Unlike past periods in history, the modern dam is designed using specific principles. The largest change in the design of a modern dam compared to the earlier dams, has been the formation of engineering schools. This changed the individualistic craftsmanship of engineering into a profession based on scientific principles. Engineers were subdivided into specific disciplines, increasing the advancements of both dam principles and construction methods. The modern embankment dam has improved...

Ecologicalenvironmental Consideration Of Dam Operation

The following observations are generalized from the literature at large. Whether any particular concern applies to any particular dam is a function of a suite of factors that might include the dam's type (e.g. concrete or earth), its purpose (e.g. hydrologic regulation, hydroelectric generation, tailings impoundment), its size, location and operating protocol (e.g. timing of drawdowns, epilim-netic versus hypolimnetic draw, peaking versus base load generation, etc.). Finally, The observations...

Gf

For typical dam concrete properties of E 30 000 MPa, Gf 0.2 N mm, and vt 2.0MPa, the limiting value is l0 < 3.0m. This limit on maximum dimension, which is much higher than the material characteristic dimension, wc, of Bazant and Oh (1983), also has often been considered stringent for large scale finite element analysis at reasonable cost. Figure 5.5 Nonlinear fracture mechanics in smeared crack propagation model To circumvent this limit on the size of finite elements, and at the same time...

F Kj Kj Kjjj KC

Several functional forms of equation 5.1 have been proposed in the literature. In LEFM models, a sudden release of stress on the surface is assumed with the extension of the crack. Most investigators adopt the discrete crack propagation finite element model (DCPM) with the LEFM constitutive models. Techniques to apply the LEFM criteria in smeared crack propagation finite element model have also been reported in the literature. Pekau et al. (1991) have proposed a numerical procedure to apply the...

Famous Dams Of The World

Rogun and Nurek, in Tajikistan, are among the world's highest dams. They rise to a height of more than 1,000 feet (300 meters) each. Some of the world's other major dams are Grande Dixence and Mauvoisin, in Switzerland Chicoasen, in Mexico Inguri, in Georgia Sayano-Shushensk, in Russia Mica, in Canada and Guavio, in Colombia. Three of the foreign dams that are constructed of the largest volume of materials are Tarbela, in Pakistan Lower Usuma, in Nigeria and Guri, in Venezuela. Dams that form...

Flood Control Dams

One way to avoid floods is to take the obvious precaution of living where there is no danger of high waters. It has always been convenient and often necessary to build homes and factories on the floodplains along rivers and streams and on the seacoasts. American pioneer settlers depended upon the streams for drinking water, transportation, and power to run their mills and factories. Floodplains, deep with the silt laid down by overflowing rivers, are fertile farmlands. The earliest towns and...

Ft [M U

The mass matrix M is a diagonal matrix and in general it can be a nondiagonal symmetric matrix. The forces due to elasticity can be written as where K is the stiffness matrix. A detailed description of the stiffness matrix can be found in finite element books. The damping matrix can be written as

How Dams Are Built

The methods of building dams can be envisioned by following the construction of Hoover Dam, built between 1930 and 1935. The engineers constructed a concrete arch-gravity dam at an approved cost of 174,000,000. It is as tall as a 60-story skyscraper. Its crest is 45 feet (14 meters) thick and its base, 660 feet (201 meters). It stores the entire flow of the Colorado River for two years. Much preliminary work had to be done. The engineers made geologic and topographic surveys to select the site....

Introduction

The first dams built by early man were low earth or rock structures designed to impound and divert water for agricultural use. Today's dams are a critical part of the nations infrastructure. They are vital for hydropower generation, drinking water, irrigation, navigation, recreation and flood control. Dams differ from other structure because of their size and their containment of water. Special attention must be taken to understand their behaviors The reservoir provides an extra effect of...

List of Figures

1.1 Idealized section of embankment dams a) Rock-fill dam with symmetrical clay core b) Rock and gravel dam with reinforced concrete slab 1.2 Cross-sections of several arch 1.3 Cross-section of typical concrete gravity dam 15 1.4 Cross-section of a concrete buttress dam 16 2.1 Fluid point 2.2 a)Lagrangian viewpoint b)Eulerian viewpoint 52 2.3 Moving 2.4 Volume 2.5 Rectangular Parallelpiped 2.6 Well-ordered parallel flow 2.7 Wave front movement and fluid movement 68 2.8 Moving pressure...

M i d[CoM

Since Y is a quadratic function of strain, it is positive and, thus, d is always increasing as shown in equation 5.9. This is a characterization of the irreversibility of damage. Different hypothesis have been proposed for isotropic damage model. The basic assumption in behaviour of the damaged and equivalent undamaged element will results in different model. Among several models, special attention will be given to the two models. They are mainly based on two concepts of the modelling. In the...

Reservoir Farend Truncated Boundary Condition

The truncated boundary for the finite element and boundary element modeling of the infinite reservoir was worked by so many researchers. Sommerfeld boundary condition is the most common one that is based on the assumption that at long distance from the dam face, water wave can be considered as plane wave. A plane wave can be represented by an equation of the form in which n is the normal at the truncation boundary. This represents well-known Sommerfeld radiation condition. It introduces a...

Reservoir Foundation Boundary Condition

If there is no absorption or penetration of water into the reservoir bottom, the same dam-reservoir boundary condition that was obtained previously, can be used for reservoir-foundation boundary. In case of reservoir with sediment at the bottom, we can account it in a very simplified manner. The boundary condition at the reservoir bottom relates the hydrodynamic pressure to the sum of the normal acceleration and acceleration due to interaction between impounded water and the reservoir bottom...

Safety Of Dams And Reservoirs

There are Several types of reservoirs as defined by their locations. The common type is a reservoir behind a dam in a valley. Increasing use is being made of tidal-storage reservoir for power generation along coast lines and excavated reservoirs for water storage for municipal or other use. In the latter type the excavated material commonly is employed to construct an embankment on one or all sides of the reservoir. Reservoirs and their associated dams serve many purposes including electric...

Solution Of The Reservoir Equation

Westergard's classic work (1933) on the hydrodynamic water pressure on dams during the earthquake started a new area for the researcher in this field. Westergaard's solution to wave equation for rigid dams during earthquakes was obtained based on the assumptions of dam with rectangular reservoir subjected to horizontal earthquake. In the solution, the reservoir extended to infinity in the upstream direction and the effect of surface wave was neglected. The system was subjected to the horizontal...

Strain softening of concrete and the initiation criterion

The stress-strain relationship for concrete becomes non-linear near the peak strength Figure 5.10-a . In the post-peak strain softening phase, coalescence Figure 5.10 Constitutive modelling for smeared fracture analysis a)softening initiation criterion b)fracture energy conservation e)local axis system d)closing and re-opening of cracks of the microcracks causes a gradual reduction of the stress resistance. The area under the uniaxial stress-strain curve up to the peak is taken as the index for...

The Moslem World

Arabs quickly developed their country within one century after the impact of new Islamic religious founded by prophet Mohammed. Several irrigation dams around the new power centres of Mecca and Madina, were built. The following is a summary of 7th and 8thcentury dams in central Arabia. Table 1.4 Summary of 7th and 8th century dams in central Arabia All of these dams were of the gravity type. They all have two outer walls of dry masonry and an earth or rubble core in between. The walls of some...

Embankment Dams

A broad spectrum of natural and fabricated materials have been used in the construction of embankment dams. Embankment dams are made by building an embankment of gravel, sand, and clay across a river. To prevent leakage, often a core, or inner wall, of concrete or other watertight materials is used. In a rolled-fill dam, earth is hauled by vehicles onto the dam and rolled tight with heavy machinery. In the hydraulic fill dam, earth is carried to the dam by water in pipes or flumes and also...

The Equation of the Motion

The continuity equation and the linear momentum equation was developed for finite systems and their were related to control volume. The equations give an average values of quantities or only components of resultant forces. They don't give any detail information of the flow everywhere inside the control volume. Here, we are trying to find out differential equations valid at any point of fluid. Writing continuity equation in the form of differential equation, we consider an infinitesimal control...

[MU [CU [KU f [MUg

In a MDF sytem, a system is discretized into its degrees of freedom. The number of degrees of freedom depend on the number of elements and the degree of freedom for each element. Usually in the case of concrete gravity dams isoparametric plane stress or plane strain are used. These types of elements are used for two dimensional problems. In some cases triangular elements may be used. In both plane stress or plane strain the displacement field is given by the u and v in directions of cartisian x...

Concrete Arch and Dome Dams

Gordon Dam Design Section

The ultimate complexity of design and analysis of stresses is attained in arch and dome dams. These dams are thin, curved structures commonly containing reinforcing, either steel rods or prestressed steel cables. Volume requirements for aggregate for manufacture of concrete are much less than in gravity and gravity-arch dams, but the competency of bedrock in foundations and abutment to sustain or resist loads must be of a high order. Arch dams usually are built in narrow, deep gorges in...