Bus Barn and Pit

[aggies09]

I have the plans largely complete for a new bus barn and am planning on building a pit. I have reviewed as many of the old threads that I can find but find no reference to the length needed for the pit. It appears that two feet wide and four feed deep is sufficient, but I don't know if I should plan a pit the length of the bus or just a partial length. I know that some of you have gone through this process. Please share what has worked best for you or what you would do different regarding size if you had to do it over. Thanks.

[Jon Wehrenberg]

Tony,

If you can do one the whole length by all means try to do that. Allow a little extra for steps down one end or the other.

Allow a lip cast into the concrete down both sides so you can cut some 2 X 10's and set them into the lip flush with the floor. They will support your oil pan or just provide a flat area for you to lay tools, and in the rear they will cover the pit so you can stand on them to work on the engine.

I suggest you DO NOT provide a drain in the pit, but a sump. I have a drain for the pit above the sump so I can put a pump in the sump and drain to the drain outlet. In this way I can wash down the engine and drain it into the drain, but If I accidently spill a large amount of oil or fuel or anti freeze I can pump it to containers so I do not contaminate the sewer or drain onto my property.

If you can, put air fittings and outlets at each end on the pit sidewall.

[jello_jeep]

Good thinking there, I would not have thought of that one!

I hope to build one someday!



If you can, put air fittings and outlets at each end on the pit sidewall.

[hobobimmer]

I have the plans largely complete for a new bus barn and am planning on building a pit. I have reviewed as many of the old threads that I can find but find no reference to the length needed for the pit. It appears that two feet wide and four feed deep is sufficient, but I don't know if I should plan a pit the length of the bus or just a partial length. I know that some of you have gone through this process. Please share what has worked best for you or what you would do different regarding size if you had to do it over. Thanks.

I believe our pit is 47 feet. We did not put stairs in, and plan to use lightweight plastic step stool or ladder for access. We might build wooden staircase someday. We didn't know if we would back bus in or pull in forward, so we didn't want to limit how we were able to access it.

We are SO glad Jon told us to build pit. We wouldn't attempt any of the maintenance we have done without it. We did not put ledge in (because we forgot), but Eric made several plywood support sections with 1x1's below to prevent sliding side to side. They are 5/8 inches above grade. We place orange safety cones around the part of the pit that the bus does not cover. Seems to be working well for us. We used LOTS of rebar to provide extra support so we wouldn't have to worry about catastrophic failure of walls. I might be able to find picture to post if you want to see substructure.

Deb and Eric Faires
Huntsville, TN

[rfoster]

Deb: Yes, I would enjoy seeing pics of your new pit were you and Jon repaired the Bus. If you have to--- just roll Erics chair out of the frame.:cool:

[Jon Wehrenberg]

Eric posed for these shots. Deb really did all the work.

[aggies09]

Deb,

I too would like to see photos of the subframe if you can post. Did you use standard 3500 psi concrete or did you increase the mix to a stronger formula.

Jon you might weigh in here on the concrete mix as well.

Thanks for all the comments to this thread.

[Jon Wehrenberg]

I think I have 4000 pound with fibreglass strands. The pit sidewalls were poured and then a floor with a minimum thickness of 7" was poured. There is #4 rebar at 12" intervals, both directions. BTW, reinforcing does not increase its strength for the application, but it does hold the broken pieces together. For it to contribute to the strength the reinforcing would have to be pre-stressed, something that ain't going to happen.

I think it is overbuilt, but that is OK. I think the key is to keep the pit to a maximum width of 24". With a greater width the supports or jacks can get too close to the edge. The depth of 4' is a compromise. It is too shallow to stand up and walk the full length of the coach, but it does allow you to stand upright between the wheels where all the work takes place. It is too deep if you are working up high such as to replace a tag axle Norgren or replace the spin on air dryer cartridge. Working on those you need to use a short stool or step ladder. If you look at the photo I posted above you will see the lip running full length. On my 40 foot coach which did not cover the entire pit I dropped the previously mentioned 2 X 10's into the lips to create a floor so I could walk all the way around the bus. Notice also the electric receptacle and air hose connection at the end near the steps. The white drain in the center is for the sump pump directly below it.

I disagree with Eric about the steps. They are needed in case any critters find their way into the pit. The steps allow them to get out by themselves. I would not want to find a skunk or raccoon in the pit dead or alive. We live in the country and it is an easy thing for an animal to get in the garage when the doors are open.

Don't forget to add a sewer drain, a fresh water supply and a power outlet. I know somebody that makes power outlets. She sends me my welfare check so spend your money with her. A link is on the home page. (Blatant commercialism)

[Jon Wehrenberg]

BTW, Tony....notice the grease on the floor of the pit and the steps leading down into it. It is a working pit and I do everything from washing the engine to accidently spilling oil into the pit. When it gets too bad I power wash it to get the bulk of the crud off and then pump that out of the pit via the sump pump through an oil separator so only water drains onto the property.

Plan on making a mess and then occasionaly having to deal with it. I don't like the fibreglass reinforced concrete because it wicks oil and is never smooth. I don't believe I would do that again.

[Will Garner]

Jon,

I really hate to be opposed to your statement about the rebar not contributing to the strength of the floor slab. Concrete is great in compression. It is terrible in tension. Guess what? The upper part of the floor slab is in compression but the lower part of the floor slab is in tension. In building a floor the rebar should be in the lower 1/3 of the floor slab thickness with a minimum of 2" of cover all around, including beneath it. In bridge decks there are usually two levels of rebar placed. The lower level is always more substantial (larger diameter bar and more of them) than the upper level. That is because the rebar is carrying the load when under tension not the concrete. And no, I do not design concrete slabs for a living but did build several bridges in a past career.

If in doubt have a structural engineer check it out. If you can provide him with the wheel loadings, and we all should be able to do that if we stay informed about our tire pressures, the Engineer should be able to provide a design that won't wind up being a bunch of pieces being held together by the rebar.

Hope this helps someone when doing their bus barn and pit. Ditto to all of Jon's other information.

Later ...

[Jon Wehrenberg]

Theorectically my concrete floor is fully supported by a compacted gravel base which sits on top of limestone that was blasted to form the pit.

Any resemblance on the part of my construction to sound engineering principles is purely coincidental. I believe the foreman was named Bubba and his biggest interest was in getting his six pack on payday.

Will, I don't doubt what you say, but I would never suggest there was anything remotely scientific about where my rebars are placed. I would be happy if they held the chunks of concrete together.

[mcirco]

My pit is very similar to Jon's which is no surprise since he provided me with all the specs. I still have some finishing touches to complete mine such as an oil/water seperator which I intend to obtain thru Jon's connections. The floor around the pit was done with 8" of 4000 PSI air entrained concrete with fiber mesh rein in the mix. In addition, I placed #6 wire mesh set 1 1/2" above the bottom of the slab. The subgrade must of course provide for a uniform bearing capacity with no soft spots. Proof rolling with a single axle dump truck with no visible pumping is what I use. Soil moisture content is important also and I used 4" of compacted stone fill below the slab. This is basically the standard construction in my area for heavy truck loading dock aprons. I used the same spec concrete for the pit walls and Rebar similar to Jon.

Miles and Laura Circo
2004 Country Coach 45' XLII D/S