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.

• Roads, Bridges

• Stadiums, Buildings, Towers

• Water Supply, Wastewater Treatment

• Pollution Clean Up

What projects would a Civil Engineer work on?

In your opinion, what is the most amazing Civil

Engineering Project? Why?

What are some of the common types of bridges?

BEAM

BEAM

DRAWBRIDGE

CABLE STAYED

TRUSS

SUSPENSIONARCH

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?

BEAMSUSPENSION 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 BridgeSan 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?

What Led to Difference in Behavior?

Anchor Block

Tower

Cables

Water

Deck

For More Interactive Labs and Activities on Skyscrapers, Bridges and Dams, visit:

www.pbs.org/buildingbig