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jheidt2543 (Civil/Environmental) (OP)
30 Nov 08 18:53
I am currently working on a project that is going to use Greenheart (Ocotea rodiaei), other common names are Bibiru, Siprir, Kevatuk (Guyana); I'm told the wood is reclaimed from another project.  The new use will be an architectural fence along a property line for posts and solid wall fencing.

Do you have any suggestions on where I might find structural parameters for this wood?
 
SlideRuleEra (Structural)
1 Dec 08 10:35
"Wood Handbook" by the USDA Forest Products Lab, see page 4-16 of this download:
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch04.pdf

Good luck on working with it, I understand that it is so gritty that it cannot be worked with typical woodworking tools. Historically, it was used to cover the hull of ships sailing to the arctic or antarctic - it would resist abrasion from ice flows better that must other materials.

www.SlideRuleEra.net idea

www.VacuumTubeEra.net r2d2

jheidt2543 (Civil/Environmental) (OP)
1 Dec 08 11:29
SRE:

Thanks, just what I was looking for!  I've also read that, while Greenheart is not toxic, it can cause some nasty infections from slivers under the skin - not a good wood for benches!

Thanks again!
jheidt2543 (Civil/Environmental) (OP)
1 Dec 08 19:46
SRE:

I'm baaack!

OK, I looked at the Wood Handbook for "Greenheart" and Table 4-5b on page 4-20 gives me, @ 12% moisture content:

Modulus of Rupture      =  24,900 psi
Modulus of Elasticity   =  3.25 x 10^6 psi
Work to Max. Load       =  25.3 in-pci
Compression ll to grain =  12,510 psi
Shear ll to grain       =   2,620 psi

Now, how do I get to Fb allowable bending stress, since an allowable bending stress for Greenheart is not given?

When I look up Douglas-fir, its Modulus of Rupture is 12,800, which looks like Fb is about 10% of the Modulus of Rupture, depending on grade.

I know Fb comes from various ASTM tests, visual grading and/or MSR grading, but I don't find anything similar for Greenheart.

 
 
SlideRuleEra (Structural)
1 Dec 08 20:34
jheidt2543 - I have tried several times to find a direct relationship between the Modulus or Rupture and Allowable Bending Stess... with no real success.  However, for many types of wood Fb is typically in the range from 10% to 20% of Modulus of Rupture.

IMHO (and that's all, just an opinion), assuming Fb = 2500 psi (for "clear" greenheart lumber) is reasonable. Downgrade that number based on the actual condition - maybe 2000 psi for good used material.

www.SlideRuleEra.net idea

www.VacuumTubeEra.net r2d2

jheidt2543 (Civil/Environmental) (OP)
1 Dec 08 20:40
SRE:

Thanks for confirming the fact that you couldn't find the relationship either, I checked all my wood books and even got so desperate that I looked in my strength of materials text too!  I'll think about it some more, but it seems like 10% might be the number.
dik (Structural)
2 Dec 08 10:08
Greenheart:
Moisture Content Green
Sp. Grav:  0.80
Mod Rup:   19.3 ksi
E:          2.47 x10^3 Ksi
Work to Max: 10.5 in-lbs/in^3
Comp para:  9380 psi
Shear para:  1930 psi
Comp perp:  1880 psi

Moisture Content 12%
Sp. Grav:  0.80
Mod Rup:   24.9 ksi
E:          3.25 x10^3 Ksi
Work to Max: 25.3 in-lbs/in^3
Comp para:  12510 psi
Shear para:  2620 psi
Comp perp:  2350 psi

from Encyclopedia of Wood by Stirling Publishing

Dik

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