Toothpick Suspension Bridge

By on January 5, 2009 -- Modified on December 8, 2017

I just finished this bridge a few days ago after working on it on and off for 3 months. It’s a cable stayed bridge design made with standard round toothpicks and wood glue.

The bridge is 31 inches long and just under 20 inches tall. The main road truss is 2 inches by 2 inches, constructed of beams of laminated toothpicks (3×3) and held together by individual toothpicks in a triangular truss pattern. The towers were constructed of laminated toothpick beams as well, but thicker (4×4). Then the suspension was created with 4 strands of thick string wound back and forth across the top of the towers.

I didn’t make this for any particular occasion or contest; I just wanted to see if I could make a sturdy suspension bridge. I’ve built a toothpick bridge before. It won a contest by supporting 350 lbs. over a two foot span, but obviously it was destroyed in the process. I don’t plan on testing this one, although I imagine that someday my curiosity will probably get the better of me. Besides, I really don’t think this bridge will hold nearly that much weight. I’d love any comments or pointers you guys might have. Enjoy!

There are a few more pictures of this bridge (higher resolution too) on my Flickr photostream at http://www.flickr.com/photos/razokylava/ I’d love any comments or pointers you guys might have. Enjoy!

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26 thoughts on “Toothpick Suspension Bridge”

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  1. wow. can that hold up a brick? if it can, than i might try to do it. it can give me an A.

    By mintymidget210 :) -- September 17, 2011
  2. We need to make a 1.5 m suspension bridge. We dont know what materials were gonna use. It needs to carry a 2 kg item for 10 seconds.

    By guest -- September 17, 2011
  3. very good 🙂

    By Duncanmilne22 -- June 13, 2011
  4. Technically, this is a Cable-stayed bridge. The cables run straight from the towers to support the roadbed in your bridge. A true suspension bridge would have one cable running from an abutment on one end up to and across the towers and into another abutment at the other end, with more cables running down to the roadway to attach them to the initial cable. But this is very good and I suspect it is very sturdy.

    By Kate -- March 17, 2011
  5. wow that is amazing!

    YOU ARE A GENIUS!!

    By zoe -- December 29, 2010
  6. great im doing my senor on suspension bridge. Perfect product. Thanks

    By itzMinh -- November 9, 2010
  7. this is fantastic!!!i thought that it would take at least 5 month to build.congratulations!!!

    By tigeress -- May 29, 2010
  8. This looks amazing! I wouldn’t have guessed it took 3 months, it would probably take much longer. It actually does look very professional, so congratulations on making something this detailed!

    By Samantha Krison -- May 2, 2010
  9. Wow, i am building this bridge for math with my partner lol can u gimme any tip? at all? lol

    By Jesse -- April 12, 2010
  10. Looks great! But I suspect it would not carry much load at all (so you shouldn’t bother testing it).

    Center-point loading will cause an inward load at the top of the towers. You have attempted to brace the top of the towers against this inward load via the strings to the backspan of the bridgedeck. But this only increases the bending moment in the bridgedeck, and fails to provide adequate support to the top of the tower.

    If you loaded your bridge, the bottom chords of your bridgedeck will snap quickly at centerspan, and your two towers will fall towards eachother. Try it – take a video – and prove me right!

    By Walter Bos -- March 8, 2010
  11. Awesome one 🙂 it really just took 2-3 days for it for me. i made it for my Science fair ! thanks for the idea 🙂

    By Hisham -- January 15, 2010
  12. Sweet, I had to make a bridge out of spaghetti for science. I believe mine had a 36.9:1 weight held to weight ratio. Mine could have held more but I botched the dimensions because I was OCD and kept chopping millimeters off the ends of the spaghetti so each piece would be even. I was .5 cm short of 1 foot and the bridge had to be at least 1 foot, so I had to hastily glue what little spaghetti I had left onto the end, and that is what broke. We couldn’t use string though 🙁

    Anyway. If I recall correctly you should make each string looser. It will hold more weight that way. Its the same principle behind that of why a person can hand from a vertically suspended clothesline but not a horizontally suspended one. The way a string/cable is designed makes it so it can support MUCH more weight when stressed vertically than horizontally. That is why the cables on suspension bridges are so loose, and not tight (suspension, not cable stayed), so there is more vertical support as opposed to horizontal.

    I’m actually remaking a bridge for a project in that class and analyzing the individual design components.

    By Jake -- December 10, 2009
  13. dude that was awesome. I want to make a strong brdge 4 my class. But I don’t know what kind of glue to use.

    By sammy -- December 5, 2009
  14. the title of this says toothpick suspension bridge but i noticed you said it is a cable stayed bridge, now i know they’re very similar but i have to build a model suspension and beam bridge for my science project and i didn’t know how to make a model suspension bridge. i got a sort of idea from your model but if i make something similar (don’t worry i wont copy your idea) would it be considered a suspension bridge? I’m testing the strength of a suspension and beam bridge to see which is stronger so its crucial to my project.

    By mrianda -- November 14, 2009
  15. wah wat a wonderful bridge u have done really its superb done within 3+ months its really great.

    By preeti -- October 9, 2009
  16. this is not a real toothpick bridge because it is made with other wood sticks

    By molly criley -- April 17, 2009
  17. great,
    I have participated in a contest in which i have to make a suspension brige out of props of ice cream. so i have inspired from this and it will really help me while building my suspension bridge.

    By vijay hemgude -- March 6, 2009
  18. thats awesome but will it take less time to make it if i do it every day because its for my science fair i want to use this idea but it might take too long

    By chocopie -- February 10, 2009
    • hello i love this bridge and my friend and i made it hold 600 lbs

      By Mickley -- May 11, 2009
  19. thanks 4 the idea but i can’t use string on my bridge. i can only use toothpicks and glue☺

    By punk -- January 7, 2009
  20. Wow… A whole 3 months??? If I really had the encouragement I could finish something like that… But otherwise I wouldn’t even come close…. It is a beautiful looking bridge :D, I’d think of that as a work of art 🙂 Nice Job done 😉

    By Cyrus Duong -- January 6, 2009
  21. This is a beautiful bridge! Thank you for sharing. My natural instinct is to encourage you to test it, but it would also be a shame for it to get destroyed.

    By Garrett Boon -- January 5, 2009
    • It’s getting kind of tough because my natural instinct is to test it too. Every time I look at it my brain starts making rough calculations of how much weight it could support. I’m not sure if I’ll be able to resist the impulse much longer, but if I do give in I’ll be sure to post the results.

      By razokylava -- January 11, 2009
      • sir plz can you tell that how much weight it can bear…. or what are math work of this bridge

        By zain -- January 23, 2015
    • Beautiful I cant wait to build my own

      By Vera -- February 27, 2015
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