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Section 5 Applying Technology: Producing Products and Structures
Production Structures
Some structures used for production
activities are not buildings. For example,
petroleum refineries are mixes of machin-
ery and pipelines. Irrigation systems are
constructed to bring water to farms in dry
areas. Evaporation basins are built to recover
salt and other minerals from seawater.
Another important production struc-
ture is the dam. Dams are used for con-
trolling floods, supplying water, making
recreational lakes, or generating electricity.
Several types of dams exist. One type is
called a gravity dam. This dam’s lakeside
is vertical, whereas the other side slopes
outward. The sheer weight of the concrete
the dam is made from holds the water
back. The dam on the left in Figure 17-27 is
a gravity dam.
Two more types of dams are the rock
dam and the earth dam. The earth dam is
also shown in Figure 17-27. A rock dam
looks similar to two gravity dams placed
back-to-back. Both sides slope outward.
Rock and earth dams must be covered
with a waterproof material to prevent
seepage. Clay is often used for this
covering.
A buttress dam uses its structure to
hold back the water. This type of dam is
not solid. A buttress dam uses walls of con-
crete to support a concrete slab or arches
against the water.
Tall dams holding back large quantities
of water are called arched dams. The arched
shape increases the strength of the dam.
This shape also spreads the pressure onto
the walls of the canyon where the dam is
built.
Water level
Solid
Concrete
Dam
Reservoir
bottom
Earth-Filled
Dam with
Clay Coating
Figure 17-27. The drawing shows two common types of dams. The photo shows a
gravity dam.
American Electric Power Co.