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Robert Prickett

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Posted on Wednesday, April 12, 2006 - 4:28 pm:   

I'm "throwing out an anchor"! Buying a house! And I would like to park the coach on the driveway.
How thick a reinforced slab do I need to park a 35,000 lb. coach without cracking the cement?
Darin Driscoll

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Posted on Wednesday, April 12, 2006 - 5:26 pm:   

6"
motorcoach1

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Posted on Wednesday, April 12, 2006 - 5:51 pm:   

at least 6,, mine is 8 with a 18x22 footer steal renforced and fiber added , run some 2 in conduit in case you may want to add electric later. if your in SC i have steel pour forms 8 in. in 20 ft leingth
Ron Walker (Prevost82)

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Posted on Wednesday, April 12, 2006 - 8:09 pm:   

4" concrete slab with 10mm rebar @ 16" O/C each way. 5" sand & gravel compacted to 90%.
Donald Lee Schwanke (Dontx)

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Posted on Wednesday, April 12, 2006 - 8:13 pm:   

Mine was far heavier than that, never had a crack, was only 4 in. Get good concrete, 1/2 rebar on 12 centers, have it sawed into sections a half inch deep.
vern rainville

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Posted on Wednesday, April 12, 2006 - 9:02 pm:   

I have 6" with just wire mesh, no cracks. Vern (in RI)
Ed Jewett (Kristinsgrandpa)

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Posted on Wednesday, April 12, 2006 - 9:26 pm:   

The main thing you have to do is remove the topsoil and have a good thick gravel base compacted under it. With a good enough base you could get by with 2 inches. The base is the secret to it.

Ed
john w. roan (Chessie4905)

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Posted on Wednesday, April 12, 2006 - 9:31 pm:   

I wouldn't go with less than 6 inches with rebar. All ground settles eventually, and you will get some cracks someday, but the rebar will limit the size.Uh-oh duck...here comes the "ENGINEERS".
Cliff (Floridacracker)

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Posted on Wednesday, April 12, 2006 - 10:14 pm:   

I went with 6" and rebar. I added extra cross rebar where the wheels would sit.

Mainly because I have found it very hard to put in after the fact if I was wrong.

Cliff
Donald Lee Schwanke (Dontx)

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Posted on Wednesday, April 12, 2006 - 10:23 pm:   

I had an excellent base. Every day after I had hauled some dirt in, I would run the bus back and forth over it. Well compacted!
R.J.(Bob) Evans (Bobofthenorth)

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Posted on Wednesday, April 12, 2006 - 10:32 pm:   

A uniform 4" with the steel placed properly (1" up from the base) on top of a perfectly compacted base is probably sufficient. The reality of placing concrete is that you will never get an absolutely uniform depth and you will never get the reinforcing in exactly the right spot. 6" gives you the margin for error.
JW Smythe (Jwsmythe)

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Posted on Thursday, April 13, 2006 - 12:10 am:   

14' thick, with a fallout shelter under it. :-)
bruce knee (Bruceknee)

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Posted on Thursday, April 13, 2006 - 7:32 am:   

I am not an engineer or an expert, but I used a plate tamper on the fill dirt and used 3500 psi mix with fibermesh, 4" thick, no cracks anywhere and have 2 busses sitting on it.
Dallas Farnworth (Dal300)

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Posted on Thursday, April 13, 2006 - 7:47 am:   

JW,
Talk to the engineer that did Sadaam Hussiens Shelters. I think the company is in Germany.
If your gonna buld a shelter under it, it needs to withstand enough pressure to park three busses and two trailers.
don (Bottomacher)

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Posted on Thursday, April 13, 2006 - 8:13 am:   

The best answer is to ask your local building official. The code normally requires a minimum of 2" of concrete all around the rebar. Other factors are the concrete mix (should probably be 3500 lb. mix or greater- it's cheap to make it stronger) and especially the base under the slab, which should be undisturbed or properly compacted soil. Use 6x6 mesh throughout, and it wouldn't hurt to thicken the slab under the bus' wheel path and place the rebar there, two inches above ground on chairs. It would then look like two ribbons about 2 feet wide from one end of the slab to the other under the wheel path. Maybe 6" there and 4" everywhere else. Pour the concrete as dry as you can handle it. No, I'm not an engineer, just a builder.
Casper4104

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Posted on Thursday, April 13, 2006 - 9:46 am:   

Let me echo Dontx about sawing.

Concrete shrinks when it cures - that's how it works. A large slab has to crack because the 'crete doesn't have the tensile strength to drag the ends of the pour the 1/2" or more it needs to move as the slab gets shorter(actually it has no tensile strength on paper).

By sawing the slab 1/2" deep, you create "Control joints", and the concrete will crack at the bottom of the saw cuts. It's gonna crack anyway, and the saw cuts let you take control of where it happens. Lay in a heavy bead of 'crete caulk and all is well.

The max pad we pour around here without CJ's is 20' by 20'. Anything bigger we lay in the sawcut control joints on an appropriate matrix. 12' O.C., 10' O.C., whatever fits.

Ok, somebody's going to say they have poured slabs the size of Connecticut with no joints and no cracks and newbie Casper is full of it. It's possible, but if you did you got lucky. Standard construction practice is to break out the saw, and for good reason.

Take a look at the parking area next time you stop at 7-11,,,

Casper4104
(Bus newbie, longtime engineer/designer at a chem plant)
Donald Lee Schwanke (Dontx)

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Posted on Thursday, April 13, 2006 - 10:56 am:   

My concrete was not just for show, it supported MANY busses. \image[buses]
Donald Lee Schwanke (Dontx)

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Posted on Thursday, April 13, 2006 - 11:35 am:   

Too early, eyes not working yet, second try:
bus
Casper4104

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Posted on Thursday, April 13, 2006 - 12:03 pm:   

Oh my - "Party at Don's house!".

Good looking toys Don, especially the old Mopar. Nice control joints in your 'crete too.

Casper
Brent Coursey (Busboy)

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Posted on Thursday, April 13, 2006 - 12:45 pm:   

Hey Don, Is that bus in the driveway a Harmon-Harry? I almost bought a Harmon-Harry a few years back from a guy in Michigan...it kind of looks like that one in the driveway, although the one I was looking at was Silver, Red, and Blue.
-Brent
Donald Lee Schwanke (Dontx)

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Posted on Thursday, April 13, 2006 - 1:03 pm:   

No, all GMC's. I assume you are speaking of the tan one, belonged to my brother, think it was a
1950 model 3612, city bus. The first GMC automatic tranny bus.
David Dulmage (Daved)

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Posted on Thursday, April 13, 2006 - 3:56 pm:   

Don,

I like that Dodge. Here's a Chrysler that's somehwat newer, but well preserved.

David Dulmage (Daved)

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Posted on Thursday, April 13, 2006 - 4:10 pm:   

:my picture
Donald Lee Schwanke (Dontx)

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Posted on Thursday, April 13, 2006 - 4:37 pm:   

That was a sweetie old Dodge. An old couple bought it and then both went to the nursing home within 6 months.. Son could not sell it and did not drive it, it just sat in the garage. They died, and I got it out of the garage for $75, drove it for transportation for a couple of years until a restorer talked me out of it.
john w. roan (Chessie4905)

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Posted on Thursday, April 13, 2006 - 5:11 pm:   

Cliff: You can add more rebar later if you use a very long masonary bit with a HIGH torque drill :-)
Cliff (Floridacracker)

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Posted on Thursday, April 13, 2006 - 7:21 pm:   

John,

Now your talking! :-)

4905 owners are pretty resourceful guys.

Cliff

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