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# Re: Tropical wood design calues

• To: <seaint(--nospam--at)seaint.org>
• Subject: Re: Tropical wood design calues
• From: "Lloyd Pack" <packman90(--nospam--at)qwest.net>
• Date: Wed, 26 Jan 2011 16:12:04 -0700
• Priority: normal

Hello Erik,

I found some information in a copy of the USDA Wood Handbook.

Ipé (Tabebuia spp.) Specific Gravity: 0.92 (green)
The following will be for green state as well.

Modulus of Rupture = 22,600 psi
Modulus of Elasticity = 2.92 x 10^6 psi
Work to Maximum load = 27.6 in-lbs/cu. in.
Compression parallel to grain = 10,350 psi
Shear parallel to grain = 2,120 psi

The following will be dry (12% moisture)

Modulus of Rupture = 25,400 psi
Modulus of Elasticity = 3.14 x 10^6 psi
Work to Maximum load = 22 in-lbs/cu. in.
Compression parallel to grain = 13,010 psi
Shear parallel to grain = 2,060 psi

I didn't find anything about these numbers being raw data or
having a F.S. already incorporated.  I did compare the listed
numbers for the Doug-Fir that I usually design to and found that
some of the numbers, like shear, Fv, were almost 10 times higher
in their tables over the NDS listed number of 95 psi.  Then on
the Compression perpendicular to grain it was almost the same,
625 psi in the NDS and 380-900 psi in the Wood Handbook.

I hope that this helps.

Take Care,
Lloyd Pack

On 26 Jan 2011 at 12:56, erik_g(--nospam--at)cox.net wrote:

> I have an architect that wants to use Ipe hardwood for stair treads,
> but there are only 2 stringers and it will span 4ft. I have searched
> everywhere and I can't seem to find allowable design values for this
> tropical hardwood. I have found bending stress values, but I believe
> that they were average values from the raw data and they did not
> include a F.S.
>
> Does anyone know where I might be able to find this info?
>
> Thanks
>
> Erik Gibbs
> http://structuresinc.biz
>