Bridges and Tunnels
By Donna Lapham
Bridges and tunnels are lifelines
Engineer – Someone who uses sci & math to design &
construct structures such as buildings, bridges & tunnels.
Level – tool made w/a tube holding liquid w/an air bubble.
Surveyor- someone who uses math to measure angles,
distances & elevations on earth’s surfaces
Arch- a curved structure in the shape of an upside-down U.
Force- a push/pull that changes an object’s motion.
Physics- the sci of how matter & energy work together.
Chemistry- the sci of how substances combine, interact, &
change.
BRANCHES OF ENGINEERING
Chemical Engineering- uses sci to convert raw materials &
chemicals into things people can use such as food & energy
products.
Civil Engineering-designing & building bridges, buildings,
dams, highways & tunnels.
Computer Engineering- designing technology such as
computer software, hardware, operating systems, &
computer networks.
Electrical E- Designing electrical systems & electronic
products
Mechanical E. – Designing mechanical systems such as
engines, tools & machines
THE ENGINEERING DESIGN PROCESS
Identify the
Problem
Redesign
w/improve
-ments
Brainstorm
possible
solutions
Evaluate
the
outcome
Design and
draw a plan
Test the
prototype
Build a
prototype
Loads-applied force or weight
Tension- is a pulling force that pulls or stretches a material
outward.
Compression- is a pushing force that squeezes or presses a
material inward.
Shear - a sliding force that slips parts of a material in
opposite directions
Torsion- Twisting force that turns or twirls a material.
Tents:
Structure – the parts of a building that keep it up
Function – the parts of a building that make it useful
Skeleton – columns and beams of a building
Skin – walls and roof of a building
Stayed – held up
Bridges
Arch bridges – simple bridges for short spans
Keystone – wedge-shaped stone at the top of
the arch that holds it in place
Ex: Roman stone bridges
Ex: later English steel bridges
Post and Beam bridges – made of
vertical posts and horizontal beams
Limited in length by weight the beams
can hold
Truss bridges – bridges that include
extra supports, usually using triangle
shapes
These allow wind to pass through well
Cantilever bridge – bridges that include
two or more cantilevers. They are very
expensive to build.
Cantilever – a beam that is only supported on one end
The left and right people in
this picture each have two
cantilevers (using their
arms) that are attached to
a span in the middle that
clearly is supporting another man. The weights on the ends
help to stabilize the structure.
Suspension bridge – A roadway
supported by two or more main towers
that is connected by large main and
many smaller vertical cables. This can
span very wide spaces.
Ex: Brooklyn bridge
Ex: Golden Gate bridge
Ex: Tacoma Narrows bridge
Cable Stayed bridge – supported by
one or more main towers with many
diagonal cables that are connected
directly to the roadway. They don’t
need anchoring weights at the ends and they can curve.