http://www.pbs.org/wgbh/buildingbig/bridge/basics.html

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

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 Switzerland

"Golden Gate" San Francisco

Brooklyn New York

AustraliaPEI - New Brunswick

Edinburgh

France

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!

http://app.discoveryeducation.ca/search?Ntt=bridges

Understanding__Bridges video.asf

WORKSHEET with answers.docx

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

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

TYPES OF BRIDGES

12.9 km (8 mi)

Confederation Bridge

Longest Bridge inCanada!

BEAM BRIDGES

What is the NAME of this kind of bridge?

http://www.youtube.com/watch?v=hsbcqa94ID0

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

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.)

Beam Bridge

DEMOIf 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 it was folded the long way.The strongest bridge

held:

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:

- 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.

abutments abutments

Keystone

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

Suspension Bridge

Cable Stayed Bridges

What type of bridges are these?

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.

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.

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 -

Covered Bridge???

What type of bridges are these?

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?

- Helps keep the road safe from weather - people could take cover during a big rain, during big windstorms, the bridge didn't get covered in ice, and so on. - Helped in the olden days so that the horses didn't get freaked out by the water underneath. - People used to sneak into the bridges to kiss each other. - 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 pilingup and adding more weight to the bridge!

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?

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:

You can use glue on PAPER

DO NOT glue on popcicle sticks(we want to recycle them!)

Must span a 30cm gap between desks

(1 full ruler)

The blue car must be able to drive through it!

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 BridgeThe 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: Bridge of your Choice with a Budget in mind.

http://www.youtube.com/watch?v=n8iCAscKOHE

Has anyone every heard of the 3 Billy Goat Gruffs before?

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 Goat Farm without falling in to the river where they would get gobbled up by the big bad troll!

The goat farm is running low on money these days, so they are only allowing you 20 Bridge Bucks to buy your bridge materials with!

Each group will be given their own color of Bridge Bucks as well as 3 'tape taxes' to help build the bridge with. The materials to build your bridge will be

sorted into piles that you will have to purchase tomorrow. You will have to be smart about WHAT to spend 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!

bridge FINAL PROJECT.docx

Your Building Partners: Orange

YellowLight Blue

Dark Blue Red

Light GreenPink

Peach

Dark Green

Meet the goats. Come grab your "Final Project Baggie" packages. Read the instructions and begin planning and brainstorming with your partner!

10 bridge bucks.docx

Teacher Resources

tape tax.docx

description of bridges.docx - review handout with all of our types of bridges

bridge FINAL PROJECT.docx

Lesson Plans

cantilever, truss, intro to final project.docx

Day 2 Sale and building.docx

Day 3 testing final bridge.docx

Day 1 buying and building.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