Salt storage shed building

[ajk1]

For the design of a large enclosed shed building that will store salt for winter use to de-ice roads, I would think that we should design all components as though they are in a corrosive environment.

The salt will be piled to about 7 m height, and the distance from top of salt pile to underside of the long span steel roof joists is another 6 m (for a total of 13 m from floor to underside of roof joists).
The joists span about 22 m.

Questions:

If anyone can answer or provide your experience relative to any or perhaps all of the following questions, it would be most appreciated.

1. Is there any more or less "standardized" design, or standardized corrosion protection principles or specifications for salt storage buildings?

2. Do you agree that the steel joists should be protected as though they were in a significantly corrosive environment?

3. For corrosion protection, I prefer hot dip galvanizing rather than a coating system, but is 22 m too long for hot dip galvanizers to deal with in Ontario?

4. If we have to use a paint coating system, which systems have been used in salt storage buildings? I have an aversion to epoxy coatings as the primary protection system because the epoxy tends to run away from sharp corners and it is nearly impossible to get the specified coating thickness at the corners. If a paint system must be used rather than galvanizing, my preference is a good quality zinc-rich paint, applied over properly cleaned steel, and then some type of durable protective paint over the zinc-rich.

5. Should the joist components be selected to minimize inaccessible surfaces? example, should the chords be HSS sections rather than double angles back-to-back?

6. Is there something more appropriate to use for the roof rather than steel joists?

7. What is the most appropriate deck over the joists? Is galvanized steel deck ok? Will salt accumulated on the top chord of the joists between the deck flutes? I suppose I should discuss this with steel deck supplier as well, but I am interested in any comments.

 

[JStephen]

Once upon a time, we quoted a silo for salt storage for a salt manufacturer, and they specified aluminum construction for it.
I've seen a lot of little dome-shaped structures for salt or sand storage, presumably concrete.

 

[Archie264]

I've seen concrete and wood used together for road salt storage and I've seen fiberglass salt tanks for industrial food preparation. I would not have much faith in steel's long term viability for that application, even if it's galvanized.

 

[jayrod12]

Am I the only one finding it hard to believe a salt storage "shed" is 40 feet tall and they're going to somehow pile salt 20 feet high. With an angle of repose of roughly 30 degrees that equals a cone that is over 60 feet in diameter.

At that size your walls will start to hold in the pile so your shed will act more like a silo.

 

[canwesteng]

I'd be wary about using aluminum unless you know the road salt is only going to be NaCl. KCl I know attacks aluminum quite aggressively I assume other salts like CaCl may do something similar.

 

[Canuck67]

The majority of the salt storage 'beehives' in southern Ontario are wood framed domes supported on concrete ring walls, although a bunch of them did collapse last winter.

 

[EngineeringEric]

The "although a bunch of them did collapse last winter." does not lend much confidence in this approach.

 

[Jacst3]

I believe using wood with concrete foundations is very standard. We had a vendor design a salt storage shed for a project. I was under the impression that they do many similar structures. The building was 80' X 26'X27' High, gable roof with wooden trusses. The foundations used were all plain concrete with minimal reinforcing and designed by the supplier. The structure was treated lumber, with strut-braced walls all around.

You can try to talk more to the manufacturer. Our contractor used Wheeler Lumber, located in Minnesota.

 

[OHIOMatt]

Our DOT requires galvanized joists. The concrete contains silica fume and is reinforced with epoxy coated rebar.

 

[ajk1]

Thanks for all the comments to-date. We have designed all the walls for large lateral forces and followed these forces thru to the foundations. We also have a good handle of protecting the rebar in the walls. Epoxy coated rebar is not that great. MTO no longer uses it and it is not one of the accepted protection systems in CSA S413. But that is not what we are asking about. It is the roof joists and steel deck. The comments are all very much appreciated. And any more comments are welcome. Sounds so far that no one on this forum has done a steel roof over a salt storage. But maybe there is more to come...

 

[hokie66]

I haven't done a salt storage building either, but like others, would shy away from steel for the structure and deck, especially the deck. But I see wood as a poor solution as well, unless all the fasteners are corrosion proof. They are the weak link. That leaves concrete, maybe a precast system?

 

[jayrod12]

I think wood is a good solution honestly. Provide the connectors as stainless steel or hot-dipped galvanized and you should be fine for the expected lifetime of a building like this. My concern would only be the metal connector plates on the trusses but I can't see that much salty water getting splashed on a roof that is 20 feet above the top of the salt pile.

 

[dicksewerrat]

Call your local Highway Dept. They probably have a design for salt sheds. Look at the northern US DOT sites

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com