What is special about an arch dam?

An arch dam is a concrete dam that is curved upstream in plan. The arch dam is designed so that the force of the water against it, known as hydrostatic pressure, presses against the arch, causing the arch to straighten slightly and strengthening the structure as it pushes into its foundation or abutments.

Why are dams shaped the way they are?

The shape of the gravity dam resembles a triangle. This is because of the triangular distribution of the water pressure. The deeper the water, the more horizontal pressure it exerts on the dam.

Why dam walls are thicker at the bottom?

A dam has broader walls at the bottom than at the top to withstand the great pressure of water which increases with increase in depth.

Is the main advantage of arch dam?

Advantages of Arch Dam. Arch dams are particularly adapted to the gorges where the length is small in proportion to the height. 2. For a given height, the section of an arch dam is much lesser than a corresponding gravity dam. Hence, an arch dam requires less material and is, therefore, cheaper.

What is the design criteria for an arch dam?

Factors to be considered as contributing to the loading combinations for an arch dam are: (1) reservoir and tailwater loads, (2) temperature, (3) internal hydrostatic pressure, (4) dead weight, (5) ice, (6) silt, and (7) earthquake. Such factors as dead weight and static water loads can be calculated accurately.

Why do designers make use of arches when designing dam walls?

An arch is a strong shape for resisting the pushing force of the water behind the dam. Arch dams are usually constructed in narrow, steep sided valleys. They need good rock for their foundations, and for the sides of the valleys, to resist the forces on the dam.

How is an arch built?

The arch is a simple way of spanning a wide area with smaller stones. Wedge-shaped stones fill the space in between two outer columns or abutments. In the construction, a temporary wooden arch is used to hold the stones in place; once the central keystone is in position, the timber support can be removed.