Finding Bridges

 
How can I plan our trip?

Read about the river before beginning to explore it. This will prepare you and your child to see more. Look for river books in the Children's section of your local library.

What Should I bring?

Bring paper, pencils, pens and markers to record what you see. A pair of binoculars and good walking shoes are always a plus.

Don't forget water, sunscreen, and hats!
For children 4 to 12 years old, and their grownups

Bridges are for crossing something--water, train tracks, other roads. Bridges must be strong, and some are quite beautiful. It takes research, knowledge, and skill to design and build a bridge.

Before You Go

The three kinds are beam, arch and cable- stayed. Each one has a different shape and use. Read about the three kinds of bridges at the bottom of this page.

Write the name of each bridge on a piece of paper in your notebook: Beam Bridge, Arch Bridge, Cable-stayed Bridge. Make a sketch of what each bridge looks like.

Pack a notebook, plus pencils, pens or markers. Now get ready for your own special "bridge trip."

On Your Trip

Have everyone with you watch for bridges. Look carefully and try to remember details. Ask youself some questions:

- What is the bridge crossing: water, roads, rail tracks, etc.
- What is the bridge made of?
- Are there some bridges you hardly notice? What kinds?
- If you find other types of bridges, describe them and draw a picture.
- Which bridges do you like? Why?

Count how many of each bridge type you find. Write notes and make some drawings to help you remember what you saw.

After Your Trip

After your trip to find bridges, keep looking for them when you are biking, walking or driving in a car. We think you will begin to notice more and more bridges in your daily travels. And you'll impress your friends with how much you know!

BRIDGE INFO

Beam bridge
A simple beam bridge has a pier on each end and a strong beam across the top. We have all built beam bridges with blocks. Beam bridges are easier to build and generally smaller than other bridge types. They're quite common; highways go under or over many of them.

Arch bridge
People have been building strong, graceful arch bridges for thousands of years. The weight of the bridge and its traffic presses down on the arch. The arch "carries" that weight to abutments (end supports) which hold the arch and the roadway above it in place.

Cable-stayed bridge
A yoyo hanging at the end of the string is "suspended." The roadway of a cable-stayed bridge is suspended, too. Hundreds of steel cables run from one or two towers to the roadway. The roadway rests on supports at both ends, but the cables carry the weight, not those supports. Because all the weight is hanging from the towers, the towers must be strong, and anchored in rock or concrete. Cable-stayed bridges are expensive to build but can span almost 3000 feet. Other types of suspension bridges can span 7000 feet.