concrete floor pressure KingAir 350 ?

[RFguy]

Anyone know the hangar floor grade for a empty KingAir 350 with full fuel ( about 6000kg) ?

 

I am building a *big ish )  hangar and if I ever wanted to sell it, I might want it to be able to accomodate something bigger than what I have plans for.

 

BUT - taxiway might not be rated, and really do I need to consider accomodating something that big ?

Probably not.  dunno. 

 

or are people .organisatings with something that big might consider somewhere and something else ? 

 

should be high enough to accomodate a decent squirral.  but that's easy. (3 high, 11 wide)

 

Maybe just accomodate a good size GA twin  ?  like a Baron or a PA34 

 

Suggestions welcome.

 

 

Edited September 7, 2021 by RFguy

[facthunter]

Keep the water from getting under it and compact the whole floor. Maybe add something to the stuff you  are using and use hot mix road type  surface. If something sinks slightly, easy  to repair. Pavement depth factor is based on tyre pressures if I recall correctly None of those planes require much to land on if it's not water logged. A 380's need about 2 metres of reinforced concrete. Nev

[skippydiesel]

Should not be to hard to make a reasonable guess at the max point loading - this would then lead to a discussion with an experienced concreter or Civil Engineer - with the specifications supplied - talk to the concreter about cost.

[onetrack]

130mm thickness of 32Mpa concrete, on a compacted, well-bound subgrade will be quite adequate to support a King Air 350.  You need to also consider surface finish, coatings, and drainage for the hangar - particularly in the case of liquid spills.

 

All you ever wanted to know, and more, is in the link below ....

 

https://www.ccaa.com.au/imis_prod/documents/INDUSTRY_GUIDE_T48_Guide_to_Industrial_Floors_and_Pavements_Design_Construction_and_Specification.pdf

[Marty_d]

Wouldn't you just need 3 thick bits where the wheels will go?  Guessing that it ain't going to deviate much if you don't want to bump the wingtips on the way in.  There's no weight on any other part of the floor.

[Thruster88]

Good to see you building at cowra. At the farm out west we built large grain/machinery sheds with 150mm thick floors. Lots of harvester, truck and wheel loader traffic up to 14,000kg axle weights. No problems.

[Geoff_H]

Maximum weight is 7ton.  Pressure on concrete would be the tyre pressure.  Only problem is bending moment from ground under the concrete not fully supporting the concrete.  Tale the 7 tonne point loading ( actually less when shared between wheels) to a civil engineer or geotechnical engineer. He/she will probably tell you off the top of his head if he knows where the hangar is to be built ( they have charts about ground support capabilities).

[Bruce Tuncks]

Don't forget to put steel mesh in that concrete...  without the steel mesh, you could get some nasty steps arise in future.

And the subgrade matters, as has been said. You may need it removed and replaced with rubble to a depth of maybe a foot. And this rubble needs compacting.

The better the subgrade, the less you can make the concrete on top, 130mm is quite a good figure, with 6mm mesh.

Also, have a think about the base of the tin walls if you are going to make the floor last and use the walls as formwork.

[Geoff_H]

Sorry my advice is consult an engineer.  The edge support or restraint will determine what shear needs to be resisted at edges.  I am a mechanical engineer and I always consult a civil/ geotechnical engineer on design.  The thing that will trash the job in a few years are the assumptions that are made.  An engineer with experience will guard against making an assumption that this slab is just like one seen on the other side of Australia.  Best to find an engineer that works on structures near where your hangar will be built.

[RFguy]

thanks everyone for the input. 
slab plan is 150mm , reinforced (of course), epoxy sealed .  thickened at the edges.   there's been recent hangar built  that would provide plenty of ground info. 

 

ONETRACK , that link was EXCELLENT. 

 

Problem at the moment is the steel price. hangar price is up 30% approx from December....

 

Registered "Lachlan Valley Avionics"

 

 

 

 

 

Edited September 8, 2021 by RFguy

[skippydiesel]

1 minute ago, RFguy said:

thanks everyone for the input. 
slab plan is 150mm , reinforced (of course), epoxy sealed .  thickened at the edges.   there's been recent hangar built  that would provide plenty of ground info. 

 

ONETRACK , that link was EXCELLENT. 

 

Problem at the moment is the steel price. hangar price is up 30% approx from December....

 

Registered "Lachlan Valley Avionics"

 

 

 

 

 

You would have to work out if the savings are worth the hassle; Marty d's comment might be explored. Perhaps not to the point of "3 thick bits where the wheels will go" as this would limit the aircraft applications but certainly aa stronger are within the pad .

 

11 hours ago, Marty_d said:

Wouldn't you just need 3 thick bits where the wheels will go?  Guessing that it ain't going to deviate much if you don't want to bump the wingtips on the way in.  There's no weight on any other part of the floor.

 

[RFguy]

Actually MartyD I have seen shallow steel channel (to confine the wheels)  put on the surface to guide in large aircraft through narrow openings.

 

802 Air tractor is actually bigger than a KingAir (width). but nice fat tyres ease up the peak mega pascals a bit. 

 

[facthunter]

Find out what the soil substrate is. If there's buckshot gravel and any water about you will be compromised.. A large slab will inevitably crack if there's clay about as it changes dimensionally with water content variation. Where is the water table? It's dead easy to bore a deep hole and insert some 100 MM pipe and see where the water table comes to with a dipstick or a float. Modern farms have these all over the place if they irrigate. .. Nev

[RFguy]

thanks Nev, yeah that will be done shortly.
KingAir tyres are only 90 psi. (620kPa) (x2 per side) . bugger all. 

Sounds like the preparation UNDER the slab is more important than the slab thickness (although thickness affects its ability to load spread of course) 
 

[RFguy]

Hangar outer width is 19.0m. between the uprights is 18.7m

Air tractor is 18.2m width . which is a big one to swallow 

I think it might be easier , if an air tractor needs electronics work, to just walk across and a tool cart  the apron to the air tractor hangars, where they all live. 

 

or a set of bifold doors that cost about as much as the Jabiru.

 

 

Edited September 8, 2021 by RFguy

[Geoff_H]

Sorry my advice is consult an engineer.  The edge support or restraint will determine what shear needs to be resisted at edges.  I am a mechanical engineer and I always consult a civil/ geotechnical engineer on design.  The thing that will trash the job in a few years are the assumptions that are made.  An engineer with experience will guard against making an assumption that this slab is just like one seen on the other side of Australia.  Best to find an engineer that works on structures near where your hangar will be built.

 

Don't put pads under the slab unless specifically designed and built correctly.  They can actually make the slab weaker

[facthunter]

You can get a bigger wingspan in  by having it sit on tracks that bring it in part sideways.. For this bigger sized stuff you need something to tug it with generally clipping onto the nosewheel axle ends. Try to make the Hangar vermin proof and you need thick plastic under the concrete to prevent water (and salt) coming up through it. Consider a sloping floor if you want to wash the plane there but you really don't want the water around. A dead flat floor provides a better base for using a laser for any rigging/check if you're repairing/building but you don't want it dead smooth or you will slip on it (one day). Nev

Edited September 8, 2021 by facthunter

[RFguy]

Geoff, I am not designing the slab, but I like to know what is going on and why. 
Good point Nev about the sideways. an AT802 is only 36' long. hangar could swallow that sideways .

[Geoff_H]

Vertical loads that are supported on the ground had no trouble whatsoever to even a small slab full stop the problem arises when you lose support underneath the slab and it becomes a cantilevered beam. If this happens you can easily crack the slab this is what usually cracks slabs. I find it when I go to a structural engineer and force him to show me his cakes so he's not over designing it that I save a lot of money in steel

[Geoff_H]

Should be calcs not cakes

[facthunter]

The now "required"  weak points in brick walls are proof that most slabs will crack on certain soils. Don't pour the slab in one piece. Nev

[Yenn]

Reinforcing is the key. I have seen a slab about 200mm thick, reinforced with 12mm steel  at 200mm cts and it took loads from the crucible carriers at a metal smelting factory. About ten ton loads plus the vehicle weight. It cracked, but after several years of use. We replaced it with a slab with much more reo. Too long ago for me to remember exactly what was used.

I reckon for what you are looking at, that a 150mm slab with 6mm mesh at 200cts, known as F63 would probably do. Laid on a waterproof plastic membrane over at least 100mm compacted sand. The mesh to be at least 25mm off the bottom.

A civil engineer should be able to tell you exactly what you need very quickly, but I have been out of the job for too long.

[facthunter]

It will still flex. It's not seriously load carrying until it's pre stressed. Concrete has little tensile strength and certainly won't bend with a simple mesh. The engineer will only refer to a book of standards and if it cracks he will say his recommendation meets the applicable standards plus a bit if you  want to pay extra. It's still no guarantee. Nev

[spacesailor]

Ferro cement concret Does flex, without cracking.

The oldest boat in the world is at the bottom of a pond in Rome. Built from a type of concrete, by the Romans.

Occasionally brought to life for anniversary,s.

So build like the Romans with chicken wire And reo.

Try the New Ferro, using epoxy instead of cement, dammed expensive though.

spacesailor

[Marty_d]

2 hours ago, Geoff_H said:

Should be calcs not cakes

I did wonder, but I guess some wedding cakes look like they needed engineer advice.