DIY Home Improvement, Remodeling & Repair Forum

DIY Home Improvement, Remodeling & Repair Forum (http://www.houserepairtalk.com/forum.php)
-   Framing and Foundation (http://www.houserepairtalk.com/f32/)
-   -   Additional weight on Truss (http://www.houserepairtalk.com/f32/additional-weight-truss-9182/)

reprosser 05-05-2010 05:18 PM

Additional weight on Truss
 
I have a shop and tractor shed that are pole buildings with Truss roof.

I want to know how much weight I can safely hang from the bottom (joist?) of the truss. I don't want to pull an engine block, but may have needs to hang things from time to time.

I have the spec for my Truss, but I don't know how to read it.

BCDL (botom chord dead load) is listed at 5.0 psf. I hope that does not mean I can only hang 5 lbs, because I think the lights weigh that much.:p

There is other data on the spec, so let me know if I can provide more info.

Wuzzat? 05-05-2010 06:03 PM

Quote:

Originally Posted by reprosser (Post 44518)
I have a shop and tractor shed that are pole buildings with Truss roof.

I want to know how much weight I can safely hang from the bottom (joist?) of the truss. I don't want to pull an engine block, but may have needs to hang things from time to time.

I have the spec for my Truss, but I don't know how to read it.

BCDL (botom chord dead load) is listed at 5.0 psf. I hope that does not mean I can only hang 5 lbs, because I think the lights weigh that much.:p

There is other data on the spec, so let me know if I can provide more info.

5 PSF is a distributed load, you want to load it with a concentrated load.

You need to post the Area Moment of Inertia, I, in inches⁴, and
the modulus, E, in PSI.

Also, how far apart are the trusses and what distance do they span?

reprosser 05-05-2010 08:18 PM

Ill just posts the data sheet.
http://i20.photobucket.com/albums/b2...nkRd/Truss.jpg

Wuzzat? 05-06-2010 03:38 PM

From note 4, the bottom chord supports a 10 psf live load.

If no math mistakes and no incorrect assumptions,
for a 30' span and assuming 2' spacing, 2x30 = 60 sf.
10 psf with 60 sf = 600# distributed over 30'.

It's 20# per foot of span, so you could hang 30 ea. 20# weights.

For a single concentrated load in midspan, I'd ask the manuf. And ask him about the 30 ea. 20# weights; solving a textbook problem is one thing but this is the real world.

If it were a single piece of wood I could probably figure it.

reprosser 05-07-2010 01:46 AM

These trusses are used in my tractor shed. 5 trusses spaced 12 feet apart.

http://i20.photobucket.com/albums/b2...orShedDone.jpg

Wuzzat? 05-07-2010 05:16 AM

Quote:

Originally Posted by reprosser (Post 44592)
These trusses are used in my tractor shed. 5 trusses spaced 12 feet apart.

http://i20.photobucket.com/albums/b2...orShedDone.jpg

And the span doesn't look like 30', either. I'd ask the manuf.
or put up your own joist designed to carry whatever max. concentrated load you want for it. The calc. for this second option should be easy.


All times are GMT -6. The time now is 08:06 AM.