Popsicle stick bridges

[White Cat]

As part of my office's Christmas party on Friday, we're split into teams of three for a popsicle stick bridge-building contest. The bridges will be scored on height of span, length of span, and maximum load. The winner of each category gets 10 points, with the other teams getting points proportional to the winner (so if the winning length was 1 m, a 0.5 m bridge would get 5 points).

The twist is that we're not allowed to use glue, tape, or anything else that's sticky. We can only use pipe cleaners (which are provided) or "other supplies which would normally be found around the office" (so no bringing in Lego) to connect the sticks.

My team's current plan is to concentrate on building one that's as tall and strong as possible, keeping the length short to conserve materials and make it stronger. Winning the height and load categories should give us a good shot at winning overall, even if our length is very short.

There are plenty of sites out there on how to build popsicle stick bridges, but they all seem to assume that glue can be used. What's the best way to secure the structure with pipe cleaners? Are common PSB designs still workable?

[Androsphinx]

What about paperclips?

[Braedley]

Are you sure that the tallest structure will win, or the shortest? A taller structure is actually a lot stronger when loaded the way a bridge is than a shorter structure. In any case, the bridges should be judged on a length-strength product, as well as length and strength individually.

And you probably can use glue, just not hot glue, which is one of the better choices. As for using pipe cleaners, you have two options, both of which should be used: lashing, and drilling through the ends of the Popsicle sticks and tying them off.

[Phantasee]

Where the hell do you work?

[Beowulf]

I'd use paperclips, and drill holes into the popsicle sticks to secure them. If you choose that method, a truss bridge would probably be your best bet.

[Hawkwings]

Drilling holes in popsicle sticks is hard. Especially since I don't think there's an office tool that can do it.

Besides, they're very weak with holes in them.

I'd use paperclips to lash them together. They're stronger than pipe cleaners.

[aerius]

Kind of a pretty far out idea, but plastic bags. Offices should be littered with plastic bags. Melt them down, dip the popsicle sticks in the molten plastic, and stick them together. Not exactly recommended as this is likely to create toxic fumes.

[Hawkwings]

Or you could just drop all the pretenses and slaughter the other teams. I mean, that's what you were going to end up doing anyways, right? With the plastic bag fumes and all...

Since when was height of span a non-arbitrary measure of how good a bridge is?

[Darth Wong]

Another way to attach two popsicle sticks would be to cut notches in them and then fit the notches, but I don't know if that would work any better than drilling holes in them. It's not as if there's a lot of wood to work with when you're talking about popsicle sticks, and if you do it wrong then the thing just splits down the grain.

Is there no minimum span? That seems a bit silly; if that's the case, then you could make a span that's only one popsicle stick length wide, and build it tall and strong to win the other two categories.

[Phantasee]

Another way to attach two popsicle sticks would be to cut notches in them and then fit the notches, but I don't know if that would work any better than drilling holes in them. It's not as if there's a lot of wood to work with when you're talking about popsicle sticks, and if you do it wrong then the thing just splits down the grain.

Is there no minimum span? That seems a bit silly; if that's the case, then you could make a span that's only one popsicle stick length wide, and build it tall and strong to win the other two categories.

We ended up doing that for a project in Grade 7. Try getting a nail file that has the gritty stuff wrapped around, so the edge carries some to file with. It's really more trouble than it's worth, though. Pipe cleaner/paper clip lashing would be a better bet.

[Darth Wong]

If there's no maximum weight, you could effectively laminate dozens of popsicle sticks together by drilling holes through all of them and then running the pipe cleaner through all the holes. Stagger them for extension. That would give you a pretty strong structure, and a very simple one too.

Of course, you would have to explain why a drill is something you would normally find in the office.

[Beowulf]

I guess it depends on the definition a bit. When they say connect, do they mean just the materials used, or everything used in connecting the sticks?

[General Zod]

As part of my office's Christmas party on Friday, we're split into teams of three for a popsicle stick bridge-building contest. The bridges will be scored on height of span, length of span, and maximum load. The winner of each category gets 10 points, with the other teams getting points proportional to the winner (so if the winning length was 1 m, a 0.5 m bridge would get 5 points).

The twist is that we're not allowed to use glue, tape, or anything else that's sticky. We can only use pipe cleaners (which are provided) or "other supplies which would normally be found around the office" (so no bringing in Lego) to connect the sticks.

My team's current plan is to concentrate on building one that's as tall and strong as possible, keeping the length short to conserve materials and make it stronger. Winning the height and load categories should give us a good shot at winning overall, even if our length is very short.

There are plenty of sites out there on how to build popsicle stick bridges, but they all seem to assume that glue can be used. What's the best way to secure the structure with pipe cleaners? Are common PSB designs still workable?

Does the bridge have to be entirely made out of popsicle sticks? You could use books for the support and then just use the sticks to span it. Rubber bands might be an option for holding it together given they're a common office supply.

[White Cat]

Are you sure that the tallest structure will win, or the shortest? A taller structure is actually a lot stronger when loaded the way a bridge is than a shorter structure.

Are you talking about an arch structure, or the height of the trusses, or something else?

The height scoring is based on the floor to the highest point of the span (which is also where the load is placed).

And you probably can use glue, just not hot glue, which is one of the better choices. As for using pipe cleaners, you have two options, both of which should be used: lashing, and drilling through the ends of the Popsicle sticks and tying them off.

The rules are no glue of any kind.

Is there no minimum span? That seems a bit silly; if that's the case, then you could make a span that's only one popsicle stick length wide, and build it tall and strong to win the other two categories.

Well, the load testing requires a variety of objects (coffee cans, etc.) to be piled on top, so it'll need to be at least big enough to have room for everything.

If there's no maximum weight, you could effectively laminate dozens of popsicle sticks together by drilling holes through all of them and then running the pipe cleaner through all the holes. Stagger them for extension. That would give you a pretty strong structure, and a very simple one too.

Of course, you would have to explain why a drill is something you would normally find in the office.

That sounds like a very good idea. If only I can find something to drill with...

[Nova Andromeda]

Do the popsicle sticks have to be the only/primary structural element? Wiring is found all over an office (from computer cables to power cords) and they are extremely strong. One could make a suspension bridge and use the sticks to make the roadway and/or support column.

Now that I think about it, I'd like some clarification on the rules. What exactly can you use and for what purpose. I see no reason to use popsicle sticks if one is allowed to use stuff you might find in an office instead. Anything from wiring to book shelves to the carpet would make better materials.

[Darth Wong]

Do the popsicle sticks have to be the only/primary structural element?

That would seem to be implied by "popsicle stick bridge-building contest".

[Nova Andromeda]

Do the popsicle sticks have to be the only/primary structural element?

That would seem to be implied by "popsicle stick bridge-building contest".

-Perhaps, but I've lost count of the times I've seen people 'win' this sort of contest by circumventing the spirit of the game. It's especially irritating when everyone then crows about how they 'think outside of box' or are 'so inventive' blah blah blah. I recall one project where a team simply glued a bunch of spagetti together in one huge bundle and won a spagetti bridge contest. Of course, the primary structural element there was the glue and not spagetti, but that didn't stop everyone from saying how great an idea it was. It sounds like the idea is that they can use whatever they can find to tie the sticks together (no gluing though), but that everything other than the sticks has to only be used to tie the sticks together. Nevertheless, the details of the rules weren't so clear to me.
-I like your idea of effecively laminating the sticks together, but how about wrapping them with wire (stripped pipe cleaners - the compressable fluff seems like it would weaken things). One might also consider flattening out the ends of the sticks and putting groves on the sides of the sticks so that when you wrap them with wire they don't slide past each other.
-If strong anchors are allowed one might also try to find a way to take advantage of the tensile strength of popsicle sticks.

[Darth Wong]

Perhaps, but I've lost count of the times I've seen people 'win' this sort of contest by circumventing the spirit of the game.

I suppose it depends on the judges' tolerance for bullshit.

[Braedley]

Are you sure that the tallest structure will win, or the shortest? A taller structure is actually a lot stronger when loaded the way a bridge is than a shorter structure.

Are you talking about an arch structure, or the height of the trusses, or something else?

The height scoring is based on the floor to the highest point of the span (which is also where the load is placed).

That still doesn't answer my question. And no proper bridge building competition would ever load the bridges from the highest point. They would load it from the center of span. You know, where traffic goes. And even loading from the top, taller structures are still stronger, to a point (assuming all links are of equal strength). Just think it through. Which is the strongest: a bridge which is just the road deck, a bridge which has a truss below the road deck, or a bridge which has a truss both above and below the road deck. Now which one is the tallest?

And you probably can use glue, just not hot glue, which is one of the better choices. As for using pipe cleaners, you have two options, both of which should be used: lashing, and drilling through the ends of the Popsicle sticks and tying them off.

The rules are no glue of any kind.

Well that's a dumb rule.

[Caius]

How about push-pins/thumb tacks? They are office supplies and they aren't sticky. Although I'm not sure if they are long enough to fit through two popsicle sticks.

[Winston Blake]

This is my suggestion, a fairly conventional truss structure:




For example, take two layers and lash all members together to make a double-thickness. Then laminate two double-thicknesses to make a quadruple-thickness, and so-on until it's thicker than it is tall. Loading at the top has a big risk of instability - if it's too thin, it may suddenly flip onto its side and snap.

Don't take my word about all this though; I didn't do too well in Statics and Dynamics.

[Darth Wong]

With this kind of project, it's not the concept that's difficult. Anyone can simply look at existing bridges and copy their time-tested techniques. No, the real difficulty is the fabrication; you're working with crappy building materials which can easily split along the grain if you're not careful, and severe limitations on construction method.

[White Cat]

Well, we didn't win, in large part due to my misinterpreting the strength scoring. I had thought that all bridges would be tested to failure, the strongest bridge got 10 points, and the others got points based on the percentage they held compared to the winner (like in the height and length categories).

As it turned out, all three bridges were able to hold the maximum weight, and so all three got the full 10 points. This basically neutered my plan of sacrificing length for strength. In the end, our team won the height category and ended with 21 points (10 height, 10 strength, 1 length). The other teams got 22 and 25 points. The winning team got Starbucks gift cards.

Interestingly, our bridge was the only one that was primarily supported by the materials the contest was supposed to be based on (popsicle sticks and pipe cleaners). The 1st and 2nd place bridges were mainly held together by picture frame hanging wire and Ethernet cable, respectively.

The 2nd place team had tried have the centre of their span propped up by a pile of office paper boxes, and have their weights just piled on top of that. However, the rules had said that it had to be an "open span".

That still doesn't answer my question. And no proper bridge building competition would ever load the bridges from the highest point. They would load it from the center of span. You know, where traffic goes.

Sorry, I made a mistake in my last post; the loads were actually placed in the centre of the span, not the hightest point.

The rules are no glue of any kind.

Well that's a dumb rule.

It makes the construction harder, but I don't see how it's a "dumb rule".

Overall, though, the rules weren't exactly up to the objective standard of a serious engineering competition...

[Nova Andromeda]

Well, we didn't win, in large part due to my misinterpreting the strength scoring. I had thought that all bridges would be tested to failure, the strongest bridge got 10 points, and the others got points based on the percentage they held compared to the winner (like in the height and length categories).

As it turned out, all three bridges were able to hold the maximum weight, and so all three got the full 10 points. This basically neutered my plan of sacrificing length for strength. In the end, our team won the height category and ended with 21 points (10 height, 10 strength, 1 length). The other teams got 22 and 25 points. The winning team got Starbucks gift cards.

Interestingly, our bridge was the only one that was primarily supported by the materials the contest was supposed to be based on (popsicle sticks and pipe cleaners). The 1st and 2nd place bridges were mainly held together by picture frame hanging wire and Ethernet cable, respectively.

The 2nd place team had tried have the centre of their span propped up by a pile of office paper boxes, and have their weights just piled on top of that. However, the rules had said that it had to be an "open span".

-Sorry to hear you lost. Looks like the "judges' tolerance for bullshit," as Mr. Wong put it, was sufficiently high and strong it would make an excellent building material.
-As a consolation prize for Xmas, I can provide you with upgraded cynicism.
-Btw, how was it possible to misinterpret the weight test so badly? Was this just more office politics?