For a horizontal platform 12 x 4 ft, made from #1 or #2 pressure treated pine dimensional lumber, with proper post and beam construction, galvanized connectors and joist hangars, what is the recommended spacing between 2x6x4 ft joists needed to support 8,000 pounds evenly distributed across the whole 12x4 sq ft surface ? You may assume the 2x6x4 joists are single or sistered as needed or recommended.

The spacing of the joists themselves should have no other restrictions since the platform will be loaded with two cords of split green oak firewood, so I don't see anything that would preclude any specific spacing except to hold the load over time without sagging. I just don't want to make a mistake and discover I should or could have used more or less spacing width between joists. Since this is firewood I'm assuming said calculations would assume a dead load, as opposed to a live load like a deck or a subfloor etc.

Though I doubt it makes a difference, the load will be carried by six 12 in diameter Sonotube poured concrete piers, with three 4x4 posts on the back, and front, supporting 4x6x12 ft long load bearing beams resting directly on top of the posts without any cuts or slots to achieve 100% vertical loading bypassing any shear stresses. The joists will then join the back beam to the front beam, supporting the floor that will hold the firewood.

We can also assume that instead of a wood floor for the shelf surface, I'd like to use some type of heavy gauge fence wire for the floor instead, resting on top of the joists, something like a cow panel or better, a horse panel with 6 gauge galvanized welded wire (.192 diam), something like this:

https://staytuff.com/product/2x4-horse-panel/

The reason for the wire panel floor instead of a wood floor is that my previous rig used pallet wood boards for the floor, but that was a mistake because it allowed too much wood/bark/dirt detritus to accumulate on the floor beneath the stacked wood pile, which became a problem after it was invaded by mice, rats, beetles, ants, and termites etc. I thought a heavy gauge wire floor would be much better, so all that crap just falls through to the ground.

I'm pretty clever but not clever enough for this. Given the expense and level of effort and work to build it, I really want to avoid screwing this one up.

After I build the raised platform, I'll build a lightweight back and side walls with lots of ventilation and a single slant roof, prob using a corrugated pvc or galvanized roof sheeting of some type to keep rain off the stack.

What do you guys think, particularly the calculations regarding the required spacing of single or sistered 2x6x4 joists needed to avoid any sagging ?

quote:

proper post and beam construction

A few years ago, I never thought I would question what this meant.
After following some construction, stair and framing groups I think that is an open assertion?

Steel would last a lot longer than wood.

Anyone that could answer that would be very much into the weeds of building codes, and my hat is off to them. The wood storage setups I see are almost always on a concrete pad of some sort.

You are very close to calculating your own answer.

What is the weight of the dead load?

What is your definition of sag? All beams will deflect and you should give the engineer the required maximum deflection.

To minimize deflection increase the beam section height from six to ??? inches. Sistering a six inch beam does not increase its resistance to bending as much as a greater section depth.

But sistering would in fact decrease the deflection I assume, since sistering joists is used to reduce deflection of floors under old houses, without increasing the depth of the joist itself.

The weight of the firewood load is 8,000 lbs, which I'm assuming would substitute for the "live" load, and the dead load would prob be say 5 to 10 lbs, divided by the area, is 165 lbs per sqft.

I suppose the max deflection allowed for the 48 inch joists could be, say, no more than 1/16 inch.

And the stiffness of southern pine, assuming it's dry, is whatever the specs are for dimensional lumber for that species as published by whoever is the sanctioning body for those building standards. I'm not sure what the units or definition would be, I don't remember that stuff from my statics class in college.