This bridge is a truss style bridge made out of plastic straws. This bridge can be made without using any glue. Be You may want to use different colored straws for the different pieces like I did. Be sure to look at the pictures for help and instruction.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Needed Supplies
- Plastic straws
- Straight pins Note: Be careful using the pins.
This project doesn't need any glue like some bridge projects do.
Step 2: Bridge Base Materials
For the base of the bridge we will use 20 straws.
Step 3: Bridge Base Parts: Cutting Part 1
Cut twenty straws at the point just before the flexible part of the straw. Make sure the straws that you cut are about the same length.
Step 4: Bridge Base Parts: Cutting Part 2
Cut five, .5 cm long slits at one of the ends on ten of the cut straws.
Step 5: Bridge Base Parts: Assembly
Take the end of a straw with the slits at the one end and put it in the end of the straw without slits. Push the straw in around 1 cm. You will need ten of these done. Make sure that all the straws are about the same length long.
Step 6: Truss Parts: Supplies
Get ten straws which will be used as your trusses.
Step 7: Truss Parts: Cutting
Cut ten straws before the flexible part.
Step 8: Truss Parts: Cutting Part 2
Four of the ten straws will need to be cut on one end, and the other six out of the ten straws will need to be cut on both ends. Cut two flaps out like what is shown in the pictures; that leaves two flaps which we will use later. One is longer than the other and they are parallel to each other. Remember, four of the straws only need it on one end; but six need it on both ends.
Step 9: Roof Parts: Supplies
Get eight straws for the roof.
Step 10: Roof Parts: Cutting
Cut the straws just before the flexible part.
Step 11: Assembly: Trusses Part 1
- Take a truss piece with one side with flaps.
- Take a base piece
- Put the flaps on the truss piece over the base piece, at the end of the base piece.
- Stick a straight pin through them.
- Take a truss piece with flaps on both sides.
- Put it over the base piece and the other truss piece like in the picture above.
- Stick a straight pin through the base piece and the truss piece.
- Do these steps over to make a second truss by the first one.
Also coordinate the sides of the straw where the cutouts are, to work best.
Be sure to look at the pictures for reference and instruction too.
Step 12: Assembly: Trusses Part 2
Take a truss piece that has flaps on both sides. The side with the longer flaps you put down on top of the two triangle pieces. Stick a straight pin through both ends.
Step 13: Assembly: Base
Put more base pieces onto the bottom straight pins of the bridge; until you have four. Then on your fifth one, stick three straight pins through it, and connect it to the other base pieces. Note: Make sure yours looks like the picture.
Step 14: Assembly: Roof
Stick four roof pieces onto the straight pins on the top of the truss.
Step 15: Repeat Steps 11-14
Repeat steps eleven to fourteen so you have two sides of a bridge.
Step 16: Assembly: Bridge Pieces
Align and stick the two big bridge pieces together so that you have one bridge.
Step 17: Finishing Up
Finish up by trimming and adjusting where needed.
Participated in the
Epilog X Contest