Work to maximum load

[Dennis59]

I apologize for what must be a really stupid question, but I can't seem to find a definition for this term: "Work to maximum load". It's found in

http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch04.pdf

and in other places.

Can someone give me an example of how this term is used?

Thanks!

 

[boo1]

What para or page are you finding "Work to maximum load"?

 

[Dennis59]

Page 4-3, under Strength Properties, Common Properties, gives a definition, and values are tabulated later for many species. The definition they give is pretty hard to relate to, especially given the units.
The English units are (in-lbf/in3)
For 12% moisture tamarack, which is what I am trying to evaluate, the numerical value is 7.1.

To give you a better idea of what I am trying to do - there is an existing barn (built about 1930, in good shape) made of tamarack timbers that I am trying to evaluate for some additional loads. I am familiar with allowable bending stresses for repetitive and non-repetitive members from other wood design texts I have used in the past, but I don't have anything that specifically lists tamarack. A web search on bending strength of tamarack brought up the url of my original post, but the bending strength terminology used in this book (Forest Products Laboratory, 1999, Wood Handbook) is different than what I am familiar with. I am trying to correlate "work to maximum load in bending" with some other bending stress terminology I am more familiar with. "Work to maximum load in bending" falls within the column headings for "static bending" in the url's tables.

A web search on "Work to maximum load" was not very helpful, and I did not find any posts in this eng-tips forum that included this phrase, either.

Any thoughts would be appreciated.

 

[boo1]

See the link below with design values for EASTERN HEMLOCK-TAMARACK

http://www.ppi2pass.com/Errata/ARESch09.pdf

table 9.2a

 

[Dennis59]

Thank you, boo1. That should get me through this question.
If anyone would care to further explain the "work to maximum load in bending" concept, I would appreciate that too.

 

[boo1]

The definition is given on pp3 second column mid page.

When performing structural evaluations of existing wood framed structures consider inspecting for dry rot wood, and checking. See

http://www.fpl.fs.fed.us/documnts/pdf1996/ramme96a.pdf

 

[AlohaBob]

I got the impression this was somewhat of a "toughness" quality measurement. The units look like energy/volume. I suspect the higher the stress ratings, the higher the corresponding toughness quality.

 

[Dennis59]

It looked like some kind of 'toughness' or 'energy thing' to me too, AlohaBob, but since it falls under the general column headings for "static bending" this seems confusing.

Is there a member of this forum who knows:
a) how the numerical values in this table are obtained - like an ASTM test or some other kind of standardized test procedure? and
b) how the numerical value for "work to maximum load in bending" might be used in a static bending calculation?

Thanks for the responses, folks!

 

[AlohaBob]

I make a guess, that static has a relationship to energy and work as opposed to dynamic. It may have a connection to lost energy associated with a dynamic load. So all the energy of the work to produce a failure goes into the result as opposed to 10% converted to heat. Just a guess, however, I've never heard of any of this before, much less how to design with it.