Help! Popsickle Stick Bridges!?

Question

Using no more than 75 popsickle sticks, I need to build a truss bridge. I can use white glue, popsickle sticks, and string. It needs to hold as much weight as possible! Designs and tips are appreciated!

Answer 1

I've done something similar.

Make use of triangles (strongest structure) and consider if components will be in tension or compression. Good use of the string for tension components will help avoid glue joint failures.

Answer 2

Others have covered the major points. Here are a couple of tidbits.
1) Even though you have only 75 sticks, nothing says you can't cut them to create more, shorter sticks for bracing.
2) Give your glue joints as much area as possible. In other words, glue the flat side of a stick to the flat side of another stick, not edge to edge or edge to flat.
3) Neatness counts. Not only for appearance, but also because your glue joints will be stronger.
4) Does anything say that the bridge deck has to be flat? An arched bridge deck will add strength, though the ends must be stable.
5) Give your glue plenty of time to dry - at least a whole day if not more
6) Don't forget cross-bracing to handle side-to-side loads. Once you start adding weight to the bridge, any imbalance in the load, whether from position of the weights or from your construction, will introduce forces in directions other than straight down. Your bridge must be able to withstand those forces as well.

A popsicle stick truss should be able to hold a _lot_ of weight. My son built a trussed catenary arch bridge out of toothpicks and it held over 200 lbs

Answer 3

I remember this project. We also had a specified span length too. I would not worry to much about strengths and focus on statics. . . based on your span length, figure out what the most effective design would be and then see if you can make it happen with what you have materials wise. I recommend reinforcing joints with the string and using plenty of glue to help distribute the load evenly across your popsicle sticks. Even load distribution is a big deal as an effective design poorly executed will allow the sticks to break one at a time and cause the bridge to fail prematurely.

Answer 4

I teach physics occasionally and I have done this project. There are thousands of designs on the internet. However, I built an example bridge three layers of sticks stacked in alternating directions. use tons of glue between the layers. Then I made the trusses by using triangle designes of twos and threes connected by double stacked links of sticks. Use all the glue and let it dry for two days minimum. That glue will be as hard as rock. My bridge held 200lbs.

Answer 5

Haven't you studied structural engineering?

Look at actual bridges and the truss structures used on interstate highways to put the direction signs overhead.

Railroad bridges are good examples of truss construction

Use the string as an under-hanging support for vertical sticks that support the roadbed. Kind of like an up-side-down arch.

Answer 6

I've read question and the six answers.
Very interesting project. Use a good quality glue.
Try building one from balsa wood. There is or was
a contest for this design. I believe the span was
12 inches. There are two prizes: the most total
weight, and the most total weight per weight of the
bridge.

Answer 7

Use Styrofoam to make the arch structure and then glue the sticks to it. you are able to then colour the sticks to look extra like a bridge or leave it sparkling. in case you flow to any craft keep you will get the elements. :) sturdy success! appears like exciting!

Answer 8

http://www.eweek.org/site/DiscoverE/popsicle.shtml

http://www.pegnl.ca/students/kids_activities/How%20to%20Bridge.pdf

http://andrew.triumf.ca/andrew/popsicle-bridge/

http://abcdpittsburgh.org/kids/kids.htm

http://www.lincoln.smmusd.org/science/7th%20Grade/bridges/bridge

http://www.lincoln.smmusd.org/science/7th%20Grade/bridges/truss_beam/truss_beam.htm