London Bridge is Falling
Down, my fair ladies!?!
Dr. Tracy Kijewski-Correa
Structural Engineer & Assistant
Professor
University of Notre Dame

What is a Civil Engineer?
• A Civil Engineer is an engineer trained in the design and construction of public works.

What projects would a Civil
Engineer work on?
• Roads,
Bridges
• Stadiums,
Buildings,
Towers
• Water
Supply,
Wastewater
Treatment
• Pollution
Clean Up

In your opinion, what is the most amazing Civil Engineering
Project? Why?

What are some of the common types of bridges?
BEAM
TRUSS
BEAM
CABLE
STAYED
DRAWBRIDGE
SUSPENSION
ARCH

What is the World’s Longest Bridge and What Type is It?
• Akashi-Kaikyo Bridge, Japan
• Suspension Type
• Center span of 6528 feet (about four Sears Towers long!)

What Bridge To Use?
BEAM
SUSPENSION ARCH DRAWBRIDGE

Emily Warren Roebling – first female Civil
Engineer
Chief Field Engineer of the Brooklyn Bridge
(1872-1883)

String Challenge
• Who can lift this shoe in the air only by pulling down on the string?

This is the same principle used to construct suspension bridges
Golden Gate Bridge
San Francisco, CA

Bridge Building Challenge: Step 1
• Cut two short pieces of straw, each 1.25 in. long.
• For each tower, tape two full straws to each side of the short piece of straw. Then tape the other end of the two long pieces.

Bridge Building Challenge: Step 2
• Tape one tower to the edge of a desk or chair.
• Tape the second to another desk or chair spaced 7 in. apart.

Bridge Building Challenge: Step 3
• Place another straw between the towers so its ends rest on the two short pieces.
• This straw is your bridge deck.
• Now you have a simple beam bridge.

Bridge Building Challenge: Step 4
• Make a load tester by unbending a large paper clip into a V shape
• Poke the ends through a paper cup at opposite sides, near the edge
• Use a second paper clip to hang the load tester over the bridge deck
• Record how many pennies the paper clip can hold before the bridge fails. How does it fail?

Bridge Building Challenge: Step 5
• Now cut 4 feet of floss (cable)
• Tie the center around the middle of a new straw
• Place the new straw between the towers to replace the damaged deck
• Tie the floss tightly to the top of the towers
• Record how many pennies the paper clip can hold before the bridge fails. How does it fail?

Bridge Building Challenge: Step 6
• Repair any damage to the towers.
• If necessary, cut another 4 feet of floss (cable) and tie the center around the middle of a new straw
• Place the new straw between the towers
• Pass the cable over the top of the towers

Bridge Building Challenge: Step 7
• To anchor the bridge, wrap each end of the cable around a paper clip.
• Slide the paper clips away from the bridge until the cable pulls tight.
• Tape the paper clips firmly to the desks.
• Record how many pennies the paper clip can hold before the bridge fails. How does it fail?

Anchor
Block
What Led to Difference in
Behavior?
Tower
Cables
Deck
Water

For More Interactive Labs and
Activities on Skyscrapers,
Bridges and Dams, visit: www.pbs.org/buildingbig