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Buttress dams which are known for their distinct design and construction, have more come in use over the centuries. These dams plays an important role in water resources and hydroelectric power.
Here we'll discuss the concept of the buttress dam, its main types, and
their functions and applications.
What is a Buttress Dam?
A buttress dam is characterized by its unique design that
incorporates buttresses or supports at regular intervals. Unlike a conventional
gravity dam, a buttress dam is more economical and requires less concrete. The
dam's design includes a flat or inclined deck slab or arch on the upstream
side, supported by buttresses on the downstream side. Buttress dams are
designed to handle substantial water pressure, making them effective for
reservoir storage.
Classification of Buttress Dams
There are five main types of buttress dams, each with specific characteristics tailored for different applications and geographical conditions. These include:
- Deck slab buttress dam
- Multiple arch buttress dam
- Massive head buttress dam
- Multiple dome buttress dam
- Columnar buttress dam
Deck Slab Buttress Dam
In this type of buttress dam, a deck slab is supported by
buttresses. The slab is generally inclined at an angle between 40° and 55° to
provide stability against the force of the water. The deck slab buttress dam is
usually constructed to a height of 20 to 50 meters. This type of dam can be
further classified into fixed deck slab, free deck slab, and cantilever slab.
Fixed Deck Slab Buttress Dam
In this subtype, the deck slab and buttresses are cast
monolithically, forming a solid and robust structure.
Free Deck Slab Buttress Dam
This design is used when the foundation soil is relatively
weak. Reinforcement is provided at the downstream face of the deck slab to
enhance the dam's stability.
Cantilever Type Buttress Dam
Here, the deck slab is cantilevered at both ends, and
reinforcement is provided on the upstream face.
Multiple Arch Buttress Dam
A multiple arch buttress dam consists of a series of arches
supported by buttresses. This design can accommodate larger heights of more
than 50 meters. The major drawback of this design is that if one unit is
affected, it can cause problems for the entire series of arches.
Massive Head Buttress Dam
In a massive head buttress dam, the buttress heads are
enlarged and joined to form a strong water-supporting surface. This design is
robust and resists sliding due to its sheer mass.
Multiple Dome Buttress Dam
Similar to a multiple arch buttress dam, but with domes
instead of arches. This design allows for longer spans and reduces the number
of buttresses required.
Columnar Buttress Dam
In this design, inclined columns support the dam's deck
slab. It requires a strong and stable foundation and skilled labor for
construction.
Applications of Buttress Dams
Buttress dams are widely used for various applications,
including water supply, hydroelectric power generation, and flood control. The
specific design and type of buttress dam used depends on factors such as the
topography of the site, the volume of water to be stored, and the foundation
conditions.
Historical Perspective
Buttress dams have a long history, with early embryonic
buttresses seen in some Roman dams. These dams have evolved over time to reduce
the use of costly formwork and steel reinforcement, becoming less slender with
greater heights.
Examples of Buttress Dams
Several notable buttress dams have been built around the world. The Daniel-Johnson Dam on the Manicouagan River in Quebec, Canada, is a multiple-arch buttress dam standing 214 meters high. It was completed in 1968, and has 14 buttresses in 1,314 meters of crest length.
The Latyan Dam in Iran is a massive head buttress dam built in 1967. It has a maximum height of 107 meters and a crest length of nearly 360 meters. This dam's design accommodates potential movement between the heads of the buttresses, making it suitable for seismically active areas.
Buttress dams are an important part of water resource
management and power generation. Their unique design and construction make them
a good choice for different geographical conditions and applications.
FAQS
What is a buttress dam?
A buttress dam is
a type of dam characterized by its unique design incorporating supports called
buttresses. These dams are built to manage water resources and generate
hydroelectric power.
How does a buttress dam differ from other types of dams?
Unlike
conventional gravity dams, buttress dams are more economical and require less
concrete due to their design with buttresses supporting the structure.
What are the main types of buttress dams?
The main types
include deck slab buttress dam, multiple arch buttress dam, massive head
buttress dam, multiple dome buttress dam, and columnar buttress dam.
What is a deck slab buttress dam?
It's a type of buttress dam where a deck slab is supported by buttresses. The slab is usually inclined to provide stability against water pressure.
What are the subtypes of deck slab buttress dams?
They include fixed deck slab, free deck slab, and cantilever type, each with specific features tailored for different conditions.
What is a multiple arch buttress dam?
It consists of a
series of arches supported by buttresses and is suitable for accommodating
larger heights.
What is a massive head buttress dam?
In this design,
buttress heads are enlarged and joined to form a strong surface capable of
withstanding water pressure.
What are the applications of buttress dams?
Buttress dams are
used for water supply, hydroelectric power generation, and flood control, among
other purposes.
How have buttress dams evolved over time?
Buttress dams
have evolved to reduce construction costs and become more robust with greater
heights while minimizing the use of formwork and reinforcement.
Can you provide examples of notable buttress dams?
Yes, examples
include the Daniel-Johnson Dam in Canada and the Latyan Dam in Iran, showcasing
different types of buttress dams and their applications.
What factors determine the choice of a specific buttress
dam type?
Factors such as
site topography, water storage volume, and foundation conditions influence the
selection of a suitable buttress dam type.
How important is it to consider the site's requirements
when building a buttress dam?
It's crucial to consider the specific needs of the site and the intended use of the dam to ensure the most suitable type of buttress dam is chosen for construction.
