Need Advice for Commercial Site with Semi Trucks 1

[JoeJitzu]

Howdy y'all,
I have a client who bought an existing building and site and will have semi trucks delivering loads of chicken parts for redistribution. He wants to install a gravel turn-around/maneuvering area for the trucks at the back of his building where there's an existing loading dock. There is an existing steep concrete drive entering the site and there will be a proposed concrete drive connecting from this driveway to the rear truck maneuvering area.

I'm trying to find a good spec or detail for a gravel lot suitable for semi traffic, and a spec or detail for a concrete driveway that will hold up to semi traffic, and the same for drop and curb inlets to place in the graveled area. I've asked my engineer friends and none of them have those details. For the gravel lot, I'm thinking a subgrade compacted to 95%, and then 12" of crushed limestone or granite gravel over geotech fabric, topped with 4 to 6" of 3/4" crushed stone. I'm in Georgia so inlets can probably be GDOT Standard 1019 type C with a concrete collar around the inlets in the lot itself (I'm adding curb and gutter to help contain gravel movement so some inlets will be curb inlets).

The other problem with this site as that the existing concrete driveway enters from a cul-de-sac and and is at a 19.9% grade down. Not an ideal situation by far but what I have to work with.

I'm having to regrade the drive to take out a hump that trucks will hang up on or drag. I've added a 10 to 12% transition area at the bottom which brings the regraded driveway to about 20% over it's length. From what I've read this should keep the trucks from dragging. The design vehicle is a WB-52 which, loaded, will be 70,000 lbs. so I'm specifying the driveway be concrete with a heavy broom finish or grooving and ridges to provide better traction. I'd hate for my client to find a semi truck inside his building one day due to loss of traction.

Is this the appropriate approach for the driveway? Any advice would be greatly appreciated!

Thanks!

 

[emmgjld]

To answer the questions requires detailed information on the subgrade soil profile to a depth of at least 4 feet, and then the answer will only give direction for you to pursue.
-- Such information would include: water table, with seasonal variations.
-- Soil classifications (sieve, possible hydrometer to .02mm, Atterburg Limits) for the soil profile (to at least 4 feet)
== Soil density over the profile

 

[lucky-guesser]

Maybe I missed something, but is there a reason (elevation change, water routing) that you need to build up the gravel area with 18" of material? Bring in a few tons of gravel or 1/2" crushed concrete, just enough to give yourself a couple inch layer, and call it a day. You have to add some every couple of years as needed, but all of that rock will need its own maintenance as well.

Grain elevators have areas that are just dirt, the trucks pack it down themselves. Gets a little messy during a long rain period, but quick heavy rains will just run off.

 

[dik]

That 20% slope is scary... coming from a cooler climate.

 

[TigerGuy]

USDA and the Army have manuals on gravel surfaces.

You should be able to locate them with a simple google search. They provide good guidance.