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GLOSSARY
barge
a long boat with a flat bottom
compression
a pushing force that shortens the object it
acts on
concrete
a building material made from a mixture of
water, cement, and sand or crushed stone
crane
a machine with long arms used to lift and move
heavy objects
girders
large, heavy beams made of steel or concrete
jacks
tools that can lift heavy objects
oil sands
a mix of sand, clay, water, and heavy oil
piers
pillars supporting a bridge
strait
a narrow passage of water that connects two
large bodies of water
tension
a pulling force that lengthens the object it
acts on
trusses
frameworks of beams and girders that support
a bridge
