27 thoughts on “Toothpick Suspension Bridge”

  1. 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.

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  2. 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!

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  3. 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!

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  4. 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.

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  5. 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.

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  6. 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.

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  7. 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

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  8. 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 😉

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    • 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.

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