Anyone an engineer or know how to calculate load carrying weigth of lumber?

flamingelephant

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Jun 22, 2001
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I want to figure out how much weigth a 4 ft span of 2x6 dimentional spruce lumber can take before breaking (or defecting too much) if the lumber is sitting supported by steel on 1" on either end and the weight all applied in the middle of the board. Anyone know how to figure that out?
 

Heisenberg

Lifer
Dec 21, 2001
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Originally posted by: flamingelephant
I want to figure out how much weigth a 4 ft span of 2x6 dimentional spruce lumber can take before breaking (or defecting too much) if the lumber is sitting supported by steel on 1" on either end and the weight all applied in the middle of the board. Anyone know how to figure that out?
In principle yes, but I (or whoever) would need more information about the load characteristics of the lumber.
 

flamingelephant

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Jun 22, 2001
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like the grade of the lumber? It would be a contruction spruce #2 or better. do you need more than that? what else would you need?
 

flamingelephant

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Jun 22, 2001
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The reason I want to know is that i work in a big box store and we have those large steel racks. We have been told that we are only allowed to put heavy pallets (4000 lbs+) in bays that have steel grates in them. Lots of the store just has lumber spanning between the racking. When I get up on the racking, i feel alot more stability and less movement from the wood ones than the steel ones. I want to show them that they are full of crap!
 

Evadman

Administrator Emeritus<br>Elite Member
Feb 18, 2001
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Home Depot Man to the rescue!

it doesn't matter weather you use steel grating or wood. 99.9% of the weight is carried by the beams. The weight carring capacity is based on how thick the beams are from top to bottom. 4" thick are rated to 10,000lb's on an 8' span by the manufacturer that made our racks.

The pallets do not even need the lumber or metal grating. That is just to keep the product from falling through the rack if it comes un-shrinked or for the forklift driver who doesn't know what he is doing.

besides, you are laying the 2x6's flat. They would deflect beyond alowable with me standing on them. (alowable is usually length/360)

<--- was forklift trainer for Home Depot for 3 years.

If you don't believe me, get a 1/4 pallet of rebar. This pallet is suppoed to be put on the floor in allinstances because it weighs about 4000 lbs, but will not span the racking. It will snap the 2x6's like twigs, and will bend the metal grating to the point it taco's and falls through the rack.
 

Heisenberg

Lifer
Dec 21, 2001
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The main thing you'd need to know is how much bending or shear stress the lumber could withstand.

Edit: N/m. Evadman gave a better answer.
 

silverpig

Lifer
Jul 29, 2001
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I know one way you could find out...

Unfortunately it might end up with an:

"Oh, fvck."
"Told you so."