Hans Wrote:
-------------------------------------------------------
> I have a question for you that I cannot seem to
> find an answer for.
>
> Maximum compressibility of wood
>
> The question is this, if you had a thousand ton
> weigh (stone lets say) and lowered it slowly onto
> a block of wood - a two by four say, would the
> wooden block be crushed flat or would it compress
> to a certain point and then stop - ie keeping the
> 1000 ton weight above the floor?
>
> Hans


Well, pine is a fairly soft wood, but I've seen an engine block weighing 500 lbs barely deform a pine pallet it was set down on.... it really only left marks at specific contact points (if this weight was perfectly flat & had a bottom surface area of 10', you'd only have 50lbs pressure per square foot, and only ~.35 lbs per square inch.... .35 PSI, which is NOT much pressure. But, since an engine block is NOT flat bottomed, most of the weight contacts the pallet at mountings & curved lower surfaces, eh, I'd guess resulting in something like 3.5 PSI to leave the marks I've seen.). And by contrast, this weight on 1/2" plywood leaves only mild scuffs.

So, what SHAPE of thousand ton stone are you talking about? The bigger the surface area in contact with the wood, the less the compression at any given spot. Or are you speaking of a single block in full (maximized) contact with a single 2x4? A standard 2x4 stud has a surface area of ~320 square inches on the flat. A thousand tons on that alone is a pressure of 6250 PSI..... or less than half the pressure (15,751 PSI) that exists at the bottom of the Marianas Trench. You'd get this 6250 PSI at a depth of ~14,000 feet (14.7 PSI per 33 feet of depth). Wood doesn't collapse at this depth (as numerous wrecks indicate), so all you'd get is a minor degree of compression, depending on the type of wood. You're MORE likely to have the wood splinter, due to irregularities in the stone placing unequal pressures on the 2x4, or due to flaws in the grain of the wood (unless the grain was perfectly parallel to the floor & the stone, you'd get a sideways slip effect that would split the wood). Similarly, a perpendicular grain would be prone to splintering under pressure.

I ran a search on wood strengths, and found:

Crushing strength (in PSI) of several woods:

Douglas Fir 7,000-8,000

White Oak 7,000-8,000

Red Oak 6,000-7,000

Teak 6,000-9,000

Ipe >10,000

Apitong 8,000-10,000

Meranty 5,000-8,000

Another site said:

Crushing strength:

Locust 10,180

White Oak 7,440


Now, I couldn't find the crushing strength of Lebanese Cedar (didn't the Egyptians use this a lot?), but other cedars were fairly low (low thousands). Eh, one site underscored the grain orientation issue..... Alaskan Cedar (Chamaecyparis nootkatensis) had a crushing strength of 2,880 PSI parallel to the grain, but only 410 PSI perpendicular to the grain.

Verdict, MANY woods (ranging from Firs, Oaks, Locust, to MOST tropical hardwoods) would easily support that entire thousand ton stone block (on a 2x4 made out of them) without crushing.

Hope this helps.

Kenuchelover.