New Concrete Driveway for R1S -- is 4" thick slabs enough for R1S weight?

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You should see how bad my driveway is after parking two Rivians on it.

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[Justsaygourd]

Lots of good comments here. My 2 cents as a licensed PE (structural) –

-subgrade stiffness is the most impactful variable when it comes to determining the strength of a concrete slab on grade. But my guess is you aren’t going to have the compaction tested prior to pouring concrete.

-As long as you aren’t parked on the edge of the concrete, 4” will be adequate. The concrete strength of a 4” slab, 3,000 psi, rebar at mid-depth, will have an allowable point (wheel) load of over 8,000 lbs depending on actual concrete area. That’s 8,000 lbs at each wheel.

-a nice heavy wire mesh or #3 rebar at 8” will control any shrinkage cracking during concrete curing. The steel will also help bridge any ‘soft spots’ in the subgrade.

-For exterior concrete, we spec 4,500 psi. Not for strength, but for increased durability and decreased permeability. Make sure they are air entraining for resistance to freeze-thaw cycles. Limit the water-cement ratio to 0.4.

-most cracking in slabs of this kind, in my experience, are due to lack of control joints, poor compaction or poor curing practices, not because of a strength issue. Provide joints at 10’ oc or at intervals matching the driveway width, go 10’ each way if the driveway is wider. Make sure they get cut within about 18 hours of finishing. Otherwise the concrete has already started shrinking as part of the curing process and it’s too late. Don’t let the fresh concrete bake in the sun.

Bottom line IMO, from the concrete’s perspective, there’s not much difference between an EV and an ICE.

Good luck!

 

[bikedrd]

^ this

I’m a licensed SE, but way too lazy to write anywhere near what @Justsaygourd wrote or said it any better.

 

[HighVoltOverland]

You should see how bad my driveway is after parking two Rivians on it.

I feel no pity for a household with 2 of these marvels

*cries in lonely R1T

 

[Brian A]

For any driveway (light car, heavy car...) minimum 4000psi concrete, fiber mesh, and rebar no more than 4 feet apart and minimum of 4 inches thick. All with proper compaction of base soil. If you do these things you should have no trouble with spalling, or excessive cracking. The Rivians are no heavier than a standard 2500 truck. If you live in an area that freezes don't put salt of any kind on your driveway. All concrete will eventually spall if you put salt on it. Best thing to do is get out and shovel the driveway and let the sun melt the rest. I live in Colorado and grew up in Nashville, TN. Colorado has some of the worst driveways I have ever seen because code doesn't require most of the items I mentioned above. In TN the code was much stricter. I have been doing my driveways the way I mentioned for 20+ years and have no issues while my neighbors, who spent a about $300 less and didn't do the upgrades above have had a lot of problems.

 

[ndmiller]

It's a 7000lb vehicle riding on way more that 2 sq in (3500psi). I would think the contact patch is at least 9sq in per tire, so 7000/36 or <200lbs per square inch. Maybe I'm oversimplifying?

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