# How to calculate volume of tires structure

The biggest problem with this thread was the omission of the objective in the first place. But then we’d have gone through all that “volume of a grain of sand” thing.

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Not to be too much of a wise guy, but if it were real tires and sand, shouldn’t the rings be modeled more with a U-Shaped profile to let the sand fill in the hollow part. That wasn’t pertinent to the initial problem of butting circles, but it might make a difference to the amount of sand.

I suppose, once you have contour rings for the sand pile, you could use Sandbox tools to make a more accurate shape…

Ok, sorry, I’m just making trouble instead of helping.

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Hi,
first of all, I very much appreciate all the effort that everyone who answered so far has put in order to solve this “problem”. I apologize if I didn’t specify well the main objective of the drawing, The idea is to create a somewhat pyramidal structure with tires for a schoolyard, which will be filled with sand. The tires (filled with sand) will only create the shape and give structure to the pyramid. The hole in the middle will be filled with sand as well, not with tires. So we will have have sand in the tires, just to make them heavy and difficult to move and inside the structure. I’d like to determine the volume of sand contained into this structure so I can budget for it. Since I have very little experience with using SU I imagined that there could be a simple way to find out the volume of the 3D form by just selecting the form and having SU doing some calculation for me. Still after all these contributions I am not sure which one to follow to get my goal accomplished.

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Frankly, estimating often comes down to “close enough”. I would think, you could use SU to get the general size of the thing for the number of tires involved (and they don’t have to touch perfectly, etc.) Then using that as a guide, just draw an approximate sized solid, cone shape engulfing it, more or less, and see what the volume of that is. The tires themselves might take up some volume, but probably a very small percentage.

An estimate will probably suffice given the cost of sand and transport. Sand “here” is about \$10/yard fob plus \$120/hr delivery. Washed sand will cost more. Normally dump trucks carry about 10 yards. You can order partial loads but the delivery would be the same. Placement of the sand will be laborious. Overall I think the volume of the tires (the rubber) can be omitted and excess sand, if any, stockpiled near the site.
I think I would adjust the size of the structure to fit most closely with the amount of sand you have delivered then add the tires to the existing pile and save some labor moving it.
A typical pyramid of 10 yards of sand would be ~14’ in diameter ~5.5’ high which calculates to 270ish cubic feet

I’ve become somewhat obsessed with this topic and the goal of it. I’ve had a go at the thing, to work out the total of sand required. It took (me) quite some figuring to make everything fit correctly. I used the technique shown by Jim Hamilton to create the tyre structure in this post:

The part that were a little tricky were the fact (to be tangent) each layer has unique tyres with different number of sides, so the sand that fills them for each layer (to be accurate) is unique as well. I basically filled the structure manually for each level. I probably could have merged the “inner” sand components into one, but I just left them separate kind of to show how it were done.

The tyre size I used were 225/50/17, not completely accurate modelling but a good idea of size.

If I’m honest, I would just stand there and say “that’s about x amount”, all this seems a little too labour intensive for my liking. Probably the hard way, but I gave it a shot.

TYRE PYRAMID IANT.skp (1.1 MB)

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You’re not the only one … the actual volume of the tire depends on the brand, size, and type. You used a 225/50/17 tire and I picked a 215/85/15. From the Goodyear website, I got this image:

and imported it to make a solid with the follow-me tool:

A slight variation to represent a 180/90/15 which used about 20% less material. I assume that the actual construction of this pyramid will involve various sizes and styles of tires.

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Yep that’s pretty obsessive, I don’t really know what to say!
I agree that there’s little chance the tyres will be the same which changes things up, nearly impossible. A good guess may be all you have. Unless the OP could give you a list of all the 40 different tyre sizes. That should keep you busy for a while.

I wonder if anyone has some gently used Bridgestone 59/80R63s lying about. Now that would be a playground!

Shep

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That’s the sand budget blown…

Hi guys
I am really impressed with the amount of support that I am receiving. And also with this, tire-pyramid addiction of sorts that has sprung out of my apparently innocent question.
Yes most probably the tires will end up being of different dimensions, so the best bet might perhaps be an estimation that uses bigger tires rather than small tires in order not to get short of sand. If some of the sand is left over, I am sure it can be used for a sandbox for the children. Many thanks to IanT for calculating the volume estimate, I think I can stick with this kind of calculation. How wide was the circle you used at the base? My idea was to use a circle some of 6m of diameter.

I don’t remember, I made the array of tyres of that size at a tangent to each other so the dia is fixed really. You”ll have to check the file above I posted. I need to sleep, too many late nights in the sandpit…

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the structure with a 6 meter base will take nearly 2 times more sand and tires as one with a 4.2 meter base or about 14.5 cubic meters

I applaud your approach. You will be much dryer than using Archimedes method!

@jimhami42 if you really want to be accurate you’ll be needing to calculate the almost impossible to fill spaces inside the tyres too!

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I would be more concerned on the effects of (used?) tires have on the health of the children
https://www.playgroundprofessionals.com/surfaces/rubber/health-effects-tire-rubber-exposure102

The conclusion at the end was "Additionally, with these products being in wide use around the world for more than 40 years, there are no reports of adverse effects of the playground or athletic surfaces."
Reuse of tires is a great idea.

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Though the article is more about the reuse of tires as granulate, I have experienced that there are always concerned parents around playgrounds…

https://playgroundideas.org/

Thanks for the article. Is quite informative
regards

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How do you do this? I am not sure what is the steps sequence of commands that lets you do this
Also is there any command (in the SU free version) that lets you replicate several forms around a pattern (like a circle)? In one of the sample drawings presented it looks like that the after the second tire is drafted the rest of the tires in the same circle all appear at once.
Regards