BRIDGES:
What is a bridge?
Why do we need them?
What shapes are bridges?
What are some famous bridges that you know of?
What bridges nearby do you see often?
http://www.pbs.org/wgbh/nova/lostempires/china/bridge.html
http://www.pbs.org/wgbh/buildingbig/bridge/basics.html

Do you see how this bridge is made up of cubes and trusses?
Some parts look just like our cube experiment that we did!

FAMOUS BRIDGES
London
"Golden Gate" San
Francisco
Switzerland
Brooklyn New
York
France
Edinburgh
Australia
PEI - New Brunswick

Introducing Bridges:
Video -
-How bridges hold up weight.
-What designers have to think about.
-Bridges that fail!
- Types of bridges - Write them on our worksheet!
Understanding__Bridges video.asf
WORKSHEET with answers.docx
http://app.discoveryeducation.ca/search?Ntt=bridges

"Statement" Bridge that I saw this weekend in
Calgary - a fancy version of a beam bridge!

TYPES OF BRIDGES http://8redbridges2008.wikispaces.com/Bridge+Pictures+A+Period

Longest
Bridge in
Canada!
Confederation Bridge
12.9 km (8 mi)

What is the NAME of this kind of bridge?
BEAM
BRIDGES

Beam Bridge
A beam bridge can be used when spanning a short gap that is not very high. They are usually made out of concrete or steel. In order for a beam bridge to be LONG, it has to have lots of short beams which are connected from one support column to another (typically with an arch.)
A beam bridge is the simplest and most inexpensive kind of bridge. They were also some of the earliest and simplest ones to be used - for example, the log over a river.
Beam bridges consists of a horizontal beam supported at each end by piers. The weight of the beam pushes straight down on the piers. The farther apart its piers, the weaker the beam becomes. This is why beam bridges rarely span more than
250 feet.
The beam itself must be strong so that it doesn't bend under its own weight and the added weight of crossing traffic. When a load pushes down on the beam, the beam's top edge is pushed together (compression) while the bottom edge is stretched (tension).
Example: Eraser http://www.youtube.com/watch?v=hsbcqa94ID0

DEMO
If I put a piece of paper across a span how many pennies does it hold?
How do I make this better?

- Now YOU try.
Materials you are allowed to use:
- 6 pieces of paper - can be rolled, folded, bent, and so on.
- one length of tape - can tape tubes for pillars
Here are some examples:
Test your bridge against another group's bridge.
Say what worked well about the bridge you made.

Worksheet about beam bridges -
Review
- If you drew your own picture: good!
- If you didn't: let's draw an example of one that DID work well.
What worked well:
It worked well if we folded paper like an accordion to make triangles. It only worked if

What type of bridges are these?
This arch above isn't actually a bridge, but it is a "friendship" arch that we will learn about in
Ukraine soon!
Arch Bridge

Why would we use an arch bridge?
- the arch bridges are used to span a deep gap (eg. valley). They are one of the cheaper bridges to build.
How they used to build them: abutments
Keystone abutments
- build up the supportive edges (called abutments).
- use a wooden support to lay the bricks around.
- the keystone is the final piece - it holds everything together. It is the piece in the very top that is in the middle.

Demo of a keystone
- plastercine - balls built up, keystone in the middle
- try being an arch - do the bridge. Is it easy to be an arch bridge?
- partner demonstration - your hands are the keystones

Demo: Observing the Difference that an Arch makes! arch bridges worksheet.docx

What type of bridges are these?
Cable Stayed Bridges
Suspension Bridge

Cable-stayed bridges may look similar to suspension bridges —both have roadways that hang from cables and both have towers. But the two bridges support the load of the roadway in very different ways. The difference lies in how the cables are connected to the towers. In suspension bridges, the cables ride freely across the towers, transmitting the load to the anchorages at either end. In cable-stayed bridges, the cables are attached to the towers, which alone bear the load.
A suspension bridge is the best bridge to build to span a very large body of water. the roadway or deck is easily supported by the steel bales that curve from one tower to the other.
Let's see a suspension bridge in action!
Let's see a cable-stay bridge in action!
Suspension and cable.docx

Suspension bridge one
- stand two books up. Tie a string between them. push down on the string.
- the books should collapse inwards.
Suspension #2
- set the books up again.
- this time run a string over top of them and tape them down to a desk on either side like how a suspension bridge goes.
- this time when you push down on the string the books should not fall over.
Cable stay bridge -

What type of bridges are these?
Covered ???

We are very lucky because Canada gets to brag that WE have the longest covered bridge in the world.
It is in heartland New Brunswick.
- What do you notice about the inside of a covered bridge?
- What PARTS does this bridge have that are the same or similar to other bridges we've looked at?

Lots of these bridges were built a long time ago when people started using horse carts. Their horses would have to cross a river with big heavy loads, so they couldn't just trot through the river. So they started building these bridges.
Why would they cover it?
-
Helps keep the road safe from weather - people could take cover during a big rain, during big windstorms, the bridge didn't ge
-
-
covered in ice, and so on.
Helped in the olden days so that the horses didn't get freaked out by the water
People used to sneak into the bridges to kiss each other. underneath.
Keeps the bridge under better conditions so that it doesn't have to be repaired as often (the weather deteriorates wood very quickly)
- also, the roofs were normally pointed so that snow would slide off instead of piling up and adding more weight to the bridge!

Today's Mission:
Construct a covered bridge using only the following materials:
- 4 long strips of manillatag
- one large piece of brown paper
- 20 popcicle sticks
- a given amount of tape
- your gluestick if you want to.
IDEAS?
How might we make a strong beam with these materials?
How might we make a pointed roof?
How might we make the sides and roof stay up?
Fill out the worksheet as we go along! It is a checklist, colour the smiley face after you have completed each requirement!
covered bridge worksheet.docx

RULES: Must span a 30cm gap between desks
(1 full ruler)
The blue car must be able to drive through it!
DO NOT glue on popcicle sticks
(we want to recycle them!)
You can use glue on PAPER

Cantilever Bridge
A cantilever bridge consists of a beam jutting form each side of a body of water. the beam is supported by concrete blocks or abutments. the two beams meet in the middle. if the bridge needs to be longer, a third piece or span is added between them. the beams of the cantilever bridge balance on a column in the center of each arch.
It works like 2 big diving boards facing each other.
Quick Demo - 5 books. - two standing up, 2 laid across so it is like two big
Ts standing by each other, place the last book on top to join the two Ts.

Truss Bridge
The strongest of all frameworks are those in which the beams meet to form triangles. Such an arrangement is called a truss and is based on the principle that a triangle is the hardest shape to twist or bend.
Today, trusses are still used in a wide variety of buildings. They stiffen the supporting structure of tall skyscrapers, form the framework of radio and television masts, and hold up most of the roofs in our houses, stores, offices, and schools.
A beam can be made much stronger by being connected to a truss frame that helps to hold it up.
Many of the other types of bridges incorporate trusses into them as well. Some bridges combine parts of many of the types of bridges we've looked at.

Truss Bridge Games
App called "Bridge FREE" - have to make truss bridges and it shows you in RED where the bridge is carrying the weight to.
You can also google "Cargo Bridge" and it is a fun and challenging game as well.
Both of these games make you think about how to place the trusses, what to use as abutments, how long your materials can be, and how much MONEY it costs to make bridges!
http://limexgames.com/studio/games/cargo_bridge

Final Bridge Assignment:
B ridge of your Choice with a Budget in mind.
Has anyone every heard of the 3 Billy Goat Gruffs before?
http://www.youtube.com/watch?v=n8iCAscKOHE

Your town has hired you and your partner to build a
40cm bridge out at the Billy Goat Farm.
- the goal is to make your bridge as strong as possible so that all 3 sizes of goats (our weights) can cross the bridge at the The goat farm is running would get so they are only allowing their own color of Bridge
Bucks as well as 3 'tape taxes' to help build the into piles that you will have to purchase tomorrow.
You will have to be smart about WHAT to spend bridge FINAL PROJECT.docx
your money on and it would be wise to save some of your allowance for later on in the bridge building in case you need more building supplies later on!

Yellow
Light Blue Dark Blue
Red
Your Building Partners:
Dark
Green
Peach
Pink
Light
Green
Orange
Meet the goats.
Come grab your "Final Project Baggie" packages.
Read the instructions and begin planning and brainstorming with your partner!

Teacher Resources description of bridges.docx
bridge FINAL PROJECT.docx
- review handout with all of our types of bridges
10 bridge bucks.docx
tape tax.docx
Lesson Plans cantilever, truss, intro to final project.docx
Day 1 buying and building.docx
Day 2 Sale and building.docx
Day 3 testing final bridge.docx

Final Results/ Student Examples summary and examples of bridge unit.docx

Attachments
WORKSHEET with answers.docx
Understanding__Bridges video.asf
arch bridges worksheet.docx
Suspension and cable.docx
covered bridge worksheet.docx
bridge FINAL PROJECT.docx
Day 1 buying and building.docx
Day 3 testing final bridge.docx
Day 2 Sale and building.docx
cantilever, truss, intro to final project.docx
description of bridges.docx
tape tax.docx
10 bridge bucks.docx
summary and examples of bridge unit.docx