# Bridge Building Designs

In our community they wanted to build a new bridge, so we wanted to test if the design they had in mind was the strongest. First we designed 2 different bridges, a truss bridge and a suspension bridge (which they had in mind), and tested which one was the strongest and which one should be built in our community.
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## Step 1: Materials

What you will need

- Popsicle sticks
- Hot glue
- Glue
-drill
-bucket
-weights
-string
-block of wood

## Step 2: Procedure:

Research Truss Bridges and Suspension Bridges

Sketch the two Bridges
Call the two bridges Bridge A and Bridge B. Make sure the length (40 cm), the width (1 popsicle stick), weight and material is the same for both bridges.

Hot glue is faster to use, but it isn't as sturdy as the other glue. For most of the bridge we used hot glue because we needed the glue to dry fast so that the pieces did not move.

We made sure that the weight was the same for both bridges. Both of our bridges weighed 327 Grams

## Step 3: Step 1: The walking piece

First make the two pieces of the bridge that the people walk. This piece is 1 popsicle stick wide and 40 cm long. Lay the posicle sticks out in a line. Put 4 sticks at the top and then for the next line put one half-way. Start the second line of sticks with a half a stick.

## Step 4: Step 2: Triangle Pieces

Make the triangle pieces. These will be used on both bridges. Make 11 of them.

Take the triangle pieces and connect them together. Four on each side. The remaining three will be used on Bridge B.

Lay out four popsicle sticks put two right next to each other in the middle and one on each side away from the two sticks. They should only be the length of one popsicle stick. Take one poepsicle stick and place it so it is diagonal. Then do this to the other side. Attach a popsicle stick across the whole thing to hold it together.

Now that you have the triangle pieces made put four in a row and attach them using the popsicle sticks.

## Step 5: Bridge A

Attach popsicle sticks to bridge A that suspend outward so that the triangle pieces can connect to it.

When you do this step you have to hold the triangle pieces up so that when you place them on it will fit perfectly.

## Step 6: Bridge A

Attach the triangle pieces to the bridge by pushing them onto the popsicle sticks that are suspended outward. Sorry we do not have a picture for this step. Push the two attached triangle pieces onto the popsicle sticks that are suspended outward. Look at page 7 to see a completed version of the bridge.

## Step 7: Bridge A

Take two popsicle sticks and attach them together at the ends. (Make a lot of these because they will be used on the bottom of the bridge)

Cross the popsicle sticks across the bottom to hold the bridge together and make it stand up. The more of the sticks you use the sturdier it will be. Make sure you do not make the bridge to heavy.

All you do is attach the popsicle sticks by crossing them on the bottom so that the sides stand up straight.

## Step 8: Bridge A

You should now have completed Bridge A. Bridge B is a little harder to build, but it is a better design and is much stronger.

## Step 9: Bridge B

Build the two pieces of the archway and attach triangle peices between them. Make two archways and use the remaining three triangle pieces for this.

First you make both sides of the archway and then you attach a triangle piece to connect them. Add a total of three triangle pieces to hold the whole thing together.

## Step 10: Bridge B

Attach the archway to the part of the bridge that people walk on. This piece was made at the beginning.

## Step 11: Bridge B

Extend popsicle sticks from the top of the arch to the part of the bridge that people walk on. Make triangles with these pieces because they will be stronger.

You will need to cut the popsicle sticks to make them fit properly. This part is very similar to the triangle pieces. Make triangle because it is stronger.

## Step 12: Bridge B

Add a railing so people can walk across without falling off the bridge. This piece is to add weight to the bridge and help the bridge look realistic.

Lay out the popsicle sticks and connect them using more popsicle sticks. This railing should be the length of the bridge.

## Step 13: Bridge B

Under the bridge attach triangle pieces to hold the bridge together. This part of the bridge would be in the river if this bridge was to actually be tested in a river.

This piece is to help sturdy the bridge. You attach it diagonally because it is stronger this way.

## Step 14: Bridge B

Bridge B is now completed

## Step 15: Testing the Bridge Designs

- Place bridge A over 2 tables
- Make a hole in the bridge
- Connect the rope to the bucket and pull the rope trough the hole you made, than pull the rope through a block of wood, so the weight is equal distributed over the bridge.
- Start adding weights in the bucket, till the bridge breaks.
- Now do the same thing with bridge B
Here are some of the pictures we took while we tested each bridge:
fwjs286 years ago
very good desings...triangles are a superb buliding block as the don't collapse as a square or circle or something like that do...
2 years ago
I agree 100%.
Garrett Boon4 years ago
Nice popsicle stick bridges. I especially like the looks of your arched bridge. Nicely done.
irockalot995 years ago
NICE BRIDGE!!!!!!!
Mathegenius5 years ago
How many popsticks do we need
Dino!25 years ago
how many layers are there ? is there suppose to be 2 or 3 layers ?
KEYBOARDISBROKEN6 years ago
expierence shows that usually the taller you make the bridge, the stronger it is...
Kilsmer6 years ago
if you don't mind me asking, what is your community? because there isn't many small society's where I'm from lol
james_10246 years ago
While this is a good test of design the fixings used in the model may not have the same strength (could be higher or lower!!) that those used in a full scale "production" bridge. Also the test only accounts for static point loading, not for dynamic loading e.g. people walking across it, wind etc. In the tests you are loading the bridge deck as foundations, not the structure and it is this that fail in bridge A not the structure. I suggest that if the you were to repeat the test with bridge structure resting on the table not the bridge deck you may get different results. Just FYI my University use this same method to teach basis of bridge design to undergrads, it allows you to explore the different types of bridge through experimentation rather than just in text books and on paper.