Hangar concrete specs

[Jim McDowall]

Instead of traditional steel reo look at using steel or plastic fibres (see https://fibercon.com.au/products/slabs/sfrc-floor-slabs/ for example).

As a rough rule of thumb concrete is about equal to the steel cost.

[facthunter]

150 may be enough but it will need reo. Steel re enforcing mesh. Pour it in sections and the edges will be where it moves as well as the pads the structure rests on . Roughen the surfaces or you will slip on it when its wet..  Do a $#1t job and any money you spend is wasted. How long it lasts depends on how what is beneath it is drained and compacted. Trees within say 20 metres will put roots under it if you give it time. You might have to put a ripper through occasionally to prevent that being a problem. Nev

[Jabiru7252]

What about paving bricks? Is that a silly thought? Seems a hell of a lot of money to concrete a hangar ($18K). I know of one or two hangars with no floor, just dirt. 

[facthunter]

Hotmix bitumen is the cheapest decent job as far as I'm concerned. Never seen laid bricks keep level when something drives on it. Nev

[RFguy]

would have throught that reo was mandatory.

 

for something about 350 sqM, with 6" slab, reo, earthworks bla bla bla is about 50 grand.

 

compressed dirt hangar is fine but this is a multi use space/ workshop.

[Jim McDowall]

Put on my old estimators hat, made a few phone calls and the cost (using all subbies) for a 125mm steel fibre reinforced slab with 300Wx 450D edge strip is about $90/m2. This depends on ground conditions, local contracting and concrete rates. A steel fibre reinforced slab is structurally the same as a 150mm traditionally reinforced slab which should be more than sufficient for the job unless you plan on installing compactuses or heavy machinery. BTW steel fibre reinforced slab is what is used on B1 hangars in Georgia.

Edited December 10, 2020 by Jim McDowall
clarity

[RFguy]

Hi Jim

thanks for that .

 

Yes fibre reinforcement is regularly used around the traps in many materials , its good stuff. 

 

Where is this all going. I have considering selling my small 110 sqM factory unit in canberra which I use for purely assembly work  only about 5 days a month, (and the ACT GOV  rates are $4500/year!)  and getting a place at Cowra AD. 

There is a hangar with all trims for sale there,  mezzaine at the back, full kitchen etc but its way more money than I want to spend. 

Council have 25x50m lots for 70 grand  on the airport.   would get a tall hangar so two planes can be stacked with a forklift (but 3m tall door) . 

 

would put my electronics  assembly robots in a sealed stud wall sub room  in the back of the hangar, have my plane at the front, and at the sides all mech workshop facilities for the plane. ... 

 

 

[Kyle Communications]

Just be aware a lot of council leases do not allow commercial ops in the hangar..need to check it out

 

[RFguy]

as long as they are related to aviation ops, like.. building radios, and servicing avionics ....

[Kyle Communications]

It doesnt amtter what ops..here at Ycab there are access agreements for some schools to operate from their hangars and the commercial operators do so from land that is freehold on the edge of the actual airfield perimeter so are on different land even though they can access the airfield...just make sure you know all the dots thats all

 

[RFguy]

Cowra Council  are specifically interested in aviation related businesses running out of there.

 

[Kyle Communications]

Well thats a good thing..just check all the bits and pieces..but thats what I would do..especially if your only using it 5 days a month..would pay for itself in no time

and makes it really convienient..proplem is you will do less work and more flying when your supposed to be working 🙂

 

[Yenn]

I would have thought that for a hangar that 100mm would be sufficient. I have been out of touch with the construction industry for twenty plus years, that means i have no experience with fibre reinforcing. One of the problems with mesh reinforcing was that it could get trampled to the bottom of the pour, but it is really needed within 25mm of the top surface. Any closer than 25mm could lead to moisture causing it to rust. If it is too low in the pour it does not work. Fibre reinforcing overcomes that problem as it is evenly spread through the depth.

You need 50mm sand, covered with plastic to form the sub base, That prevents moisture loss when the slab is poured.

As I said before it needs to be broken up into say 5m Sq sections to help control cracking.

The slab can be laid over the footings for the columns, or it can be laid around them. If laid around the footings there will be a need for extra reo at the corners.

It is also good practice to cary reo from one slab to the adjoining one to prevent the slabs moving in relation to each other.

There is also a need for edge thickening, to act as a rat wall and also beef up the edge, where traffic comes on to the slab.

Writing this it is coming back to me, I used to design and specify this kind of work.

Concrete strength, I forget the numbers of MPa used, but the supplier would put you right there. You need a slump of say 70mm to allow easy handling, but bear in mind that the greater the slump, the lower the strength. Finish with a "helicopter" and maybe  broomed finish, it depends upon what you want. the broomed finish can vary in roughness and it provides grip, a smooth finish can be painted or left alone.

Pour it early in the morning, keep it shaded if possible and better still flod it with water after the finishing has been done. The moisture needs to be retained as long as possible to get full strength and avoid a dusty finish.

I hate concrete, having been in the construction industry for too long and really never gave it a thought since the turn of the century.

[turboplanner]

32 minutes ago, RFguy said:

as long as they are related to aviation ops, like.. building radios, and servicing avionics ....

Clever answer, but you need Industrial Zoning, so the starting point is to go onto the State website (Google Planning Schemes +NSW) punch the Cowra address in and there will be a property report showing what the Zone is. Look up the Zone definition and you will see all the Uses permitted without a Permit, and any Uses you migght be able to conduct after obtaining a permit.

 

Biggest loss around here was a group who paid 4.5 million for a site to build a Church and found Churches were prohibited on the site. Google is free.

[Jim McDowall]

or be open with the council in the negotiation process and get their permission in writing - preferably with a DA which is a condition of the land contract

[facthunter]

I get the impression Cowra Council is more aviation minded than most. Yarrawonga did good things  too.  You can live and do work there. Makes it more secure if people are around all the time. Canberra is top price for all things..Nev

[SplitS]

Yarrawonga airfield is a great place most of the time councils are anti business in this case they should be applauded.

[skippydiesel]

13 hours ago, turboplanner said:

............................................................................................

 

Biggest loss around here was a group who paid 4.5 million for a site to build a Church and found Churches were prohibited on the site. Google is free.

I thought churches were in the aviation business.

[RFguy]

Yenn and others, thanks for the detailed steps

 

Good for when one has to oversee what the contractors are doing...

 

[onetrack]

Glen, here's a link to a White Paper that covers all the desired features and every facet of use in military and commercial hangars.

 

https://www.flowcreteaustralia.com.au/media/10815/flowcrete-australia-what-are-the-considerations-flooring-specification-for-commercial-and-military-aircraft-hangar-facilities-may-2018.pdf

 

From this article you can compile a list (write down), of what is applicable in this White Paper, as far as your particular design requirements need.

 

Many of the features mentioned are not relevant to your needs, but there may be several that are, that you didn't think of.

 

In my long experience of workshops and sheds, the greatest single problem is spills of oils and fuels that can detrimentally affect the concrete.

 

For this reason, I cannot speak too highly of epoxy or polyurethane floor coatings for a concrete floor finish. Using a lighter range colour also improves lighting in the hangar/workshop.

 

My advice is that, as with all construction, the groundwork is the most important part of the construction. It is most desirable that the area where a concrete floor is to be laid be well compacted, and of suitable soil material.

 

On that basis, if the soil structure is initially poor, as in soft sand or heavy clay with high expansion/contraction issues, moisture issues from a high water table, or inadequate drainage - it is best to excavate that poor soil and replace the excavated material with a decent depth (200mm-250mm) of good quality road base - which is then compacted to road structure levels.

 

Use a road base with fine aggregate or small stones in it, and once compacted, this alleviates the need for any sand packing under the slab. At the most, you may need a thin layer of sand to prevent sharp aggregate from penetrating the plastic sheeting.

 

I'd suggest 150mm or 5" of steel-reinforced concrete thickness is more than adequate for your hangar. The concrete ingredients MUST be accurately weighed - not roughly measured - if you want to end up with high-grade finished concrete.

Accordingly, readymixed concrete from a reputable supplier is preferred over site-mixing, as the readymix supplier will provide a concrete mix to specifications, that is consistent.

 

The concrete must be finished accurately so it is perfectly level with no undulations, which means water will pool, when you wash the floor. As a result, choose your concrete slab layers with care, based on evidence of previous good results.

[kgwilson]

I got our Aero Club hangar lean-to floor done a year ago. We have a Fergie 148 with a slasher & 2 x Iseki SF300 mowers in there. The concretor had a bobcat to level out the floor & put down crusher dust & levelled it. They also did all the form work & used steel reo on 50mm plastic chairs. No plastic lining as we don't have a rising damp issue, only flooding in Summer usually. The concrete depth is 100mm & we got it broomed for grip. Cost was $65.00/sq metre which was a reduced rate because we are a club. The job was well done & dead flat. Most of the hangars on the aerodrome have 90-100mm concrete floors or just gravel on the dirt base. Some have a concrete strip for the fuselage only & gravel either side & some have used old carpet on top of the gravel. Those with carpet usually have to replace it after a flood. 

 

My hangar has a centre fuselage strip on top of 11 truck & trailer loads of slag I got from the old brickworks in South Grafton to raise the floor 800mm from the surrounding area. After whacker packing the slag down it set really hard & I have carpet on it. It was the only hangar that did not get any water in it after the last big flood in 2013.

[RFguy]

Thanks OneTrack and KG for the info. 

 

Certainly, the oil and fuel spills will require the epoxy floor . 

I like as light colour floor as I can get- easier to see dropped nuts and bolts !!!

 

Well, we'll see what happens next.  Hangar can be made tall enough (6m) , but with 3m doors that machinery along the lines of a forklift (or other cantilever lifter)  can pick up a plane on the mains and nose  and have another in below. Have to think about how that might be done with a tailwheel !  A NON cantilever lifter like a hoist would also do it, on overhead blocks and chains and a 'tray' the whole aircraft goes up on.  would have to be sufficient to lift an RV9 etc.

 

 

[WayneL]

https://vansairforce.net/community/showthread.php?t=97594

http://armaerospace.com/products/aero-lift-aircraft-storage-lift-weight-specifications/

https://hangartools.eu/products/hangar-lifts/

[turboplanner]

A lot of good advice above; a couple more rules of thumb:

1. You never know when someone will need to come in with a truck or Forklift

2. If there are any trees around, roots will crack thin concrete, and if the ground is clay thin is temporary.

 

Having said that, the big difference bwteen concrete and compacted soil/gravel is that concrete provides a moisture evaporation barrier.

In a dirt floor shed everything made of steel develops a thin skin of powder rust; tools, shovels, parts and anything on the aircraft.

As the years go by everything develops a speckled appearance.

 

[facthunter]

Without the  thick black plastic sheet underneath, water will come up through the concrete and salt in it collects near the top as the surface dries out and osmosis draws more up from then on. Paint on the surface doesn't stop it though it might look good for a while. Dust and condensation will corrode things. IF you are serious you seal it well and keep the moisture levels  low. A small airconditioner will get rid of moisture and insulate the iron roof or water drops will form there and drop on your wing surfaces etc. The most important thing about a Hangar is will it stand high winds?. Unless braced properly the big door opening is a weakness that may cause failure  and destruction of your kite. Nev