Accuracy Of The Solution Scheme

The accuracy of the staggered solution scheme can be improved by increasing the number of iterations and or by decreasing the time step. Increasing the number of iterations of the staggering scheme is a time consuming process. The accuracy of the proposed methods is based on the selection of the appropriate time step. In all of the following analyses no iterations have been made for the purpose of improving accuracy. The staggered displacement method and the modified staggered pressure method...

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...

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....

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...

Shear resistance of fractured concrete

After the initiation of fracture process on a plane perpendicular to the direction of major principal tensile stress, it is not unlikely to expect the rotation of principal stress directions under varying deformation modes. Hence, shear deformation may take place on the partially formed rough fracture plane. The definition of shear stress-strain behaviour of concrete during the fracture process seems to be difficult. Bazant and Oh (1983) ignored the shear deformation on the fracture plane, and...

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...

Reynolds Transport Equation

Consider N as properties of a substance whose measure depends on the amount of the substance presented in a system. An arbitrary flow field of v v x, y, z, t is observed from some reference xyz. We consider a system of fluid with finite mass at time t and t At figure 2.3 . The streamlines correspond to those at time t. The control volume is considered with system at time t and is fixed. The distribution of N per unit mass will be given as n, such that N HI npdV with dV representing an element...

[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...