Can a garage floor support 2 Rivians?

[Surferdude]

The only way you'll know the slab is strong enough to handle the weight of two Rivians is to park them on the slab. No geotech or structural engineer or contractor can answer the question without destroying the slab . What's the worst that can happen... a crack forms?

Now if this was a structurally supported garage (e.g. elevated garage or over a basement or floor) then I would think hiring a professional to inspect the accessible and visible structural supports would be warranted.

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[zipzag]

I’ve actually been thinking about this a bit. Would a concrete garage with a basement be able to support 2 EVs?

Concrete garages do not have basements underneath except at the high end in urban locations where land values are very high.

Th best way to compact a garage base in typical new construction is to run water for 3-4 days. After removing all organics, of course. It just takes a little care to keep slabs from cracking. Most builders and concrete subs don't even know the basics anymore.

Curing slabs is another technology that is largely lost and only done when specified in commercial work.

 

[Dark-Fx]

Feeding and clothing 2 Rivians

Was wondering if this was going to be a PG13 reply. I can't wait to see if the R2T is going to look more like daddy R1T or mama R1T.

 

[kylealden]

The problem with asking forums for engineering advice, is any real engineer will dodge the question because of liability concerns, and any DIY hack will offer up their 2¢.

This excellent point applies equally well to legal advice.

(Apropos of nothing, it's not a bad thing to have in mind for, say, corporate communications, manufacturing, design, supply chains, etc., too...)

 

[Trekkie]

it's not the weight of the vehicle, but the distribution on the wheels that you worry about.

Concrete is usually rated at compression strength in PSI, and 3500 or so is about what you get out of 4" concrete which is what most homes made in the last 40 years have.

If you really want to figure it all out, here's a great method:

https://surjan.substack.com/p/16-weighing-a-car-with-tire-pressures?s=r

You get the contact patch size, PSI of tires. That'll tell you the weight per wheel. Or, you can see in Jehu Garcia's death valley trip video () he put his R1T on scales. He got about 1700 lbs at each wheel. Not sure what the contact patch is, but with that you can get your PSI the tires are putting on, but more than likely it's under the 3500 PSI of a 4" concrete slab in most homes. You'd have to look up your local code history to see if they ever allowed less, but in the 80s our cars were big, metal, and heavy as hell compared to modern non-ev cars so I'd be surprised if they weren't thicker.

 

[shamoo]

I think you will be fine, but to be absolutely sure (like others have said), the only way is to take concrete cores/soil samples.

Think about it this way. Two heavy cars are spread across a large area on thick rubber tires (8 total contact points). Many of us have very heavy toolboxes. My *empty* toolbox on 4 very tiny caster point loads weighs about 1700lbs. Adding tools and whatnot probably doubles it. Not as heavy as a car, but very intense point loads which probably equals more force per square inch than a tire.

 

[SeaGeo]

it's not the weight of the vehicle, but the distribution on the wheels that you worry about.

Concrete is usually rated at compression strength in PSI, and 3500 or so is about what you get out of 4" concrete which is what most homes made in the last 40 years have.

If you really want to figure it all out, here's a great method:

https://surjan.substack.com/p/16-weighing-a-car-with-tire-pressures?s=r

You get the contact patch size, PSI of tires. That'll tell you the weight per wheel. Or, you can see in Jehu Garcia's death valley trip video () he put his R1T on scales. He got about 1700 lbs at each wheel. Not sure what the contact patch is, but with that you can get your PSI the tires are putting on, but more than likely it's under the 3500 PSI of a 4" concrete slab in most homes. You'd have to look up your local code history to see if they ever allowed less, but in the 80s our cars were big, metal, and heavy as hell compared to modern non-ev cars so I'd be surprised if they weren't thicker.

I can't reply adequately right now, but no. This is the wrong use of the compressive strength.

 

[3121]

Do you have a post tension foundation? If so no problem.

 

[SyanVergio]

I had a similar concern with my garage and ended up getting a structural opinion through emersonproservices.com. They were super down to earth and explained what kind of load the slab could take without overcomplicating things. Turns out my 4" slab with good sub-base was fine for my R1T and R1S, but it's the soil compaction and reinforcement that really matter more than just the concrete thickness.

 

[Blueassassin]

https://www.corvettemuseum.org/sinkhole/

hopefully they don't make a Rivian museum.

 

[Zoidz]

Concrete has multiple strength properties - compressive, flexural, tensile, etc. They have a relationship to each other but are not the same. That is, in general the higher the compressive strength, the higher others should be.

But flexural strength ("cracking point" for this discussion), which is what a vehicle is going to stress, is only 10% - 20% of compressive strength. So 3500 psi compressive strength might be 500-700 psi flexural strength. That's where cracks could appear in an unsupported slab. If the slab has wire mesh or rebar in it, the value goes up. It should have wire mesh.

But - most garages are slabs on subsoil. Assuming proper subsoil compaction and no voids, the net strength related to vehicle cracking is somewhere in between flexural & compressive strength. Hopefully at the higher end! So it's unlikely there's much to worry about - assuming a quality slab on subsoil garage floor.

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