Depth of wood floor trusses
Depth of wood floor trusses
(OP)
I have a house with 24' spans with wood floor trusses. What is the recommended depth to limit vibrations?
Also at the ledger for the second floor trusses, where the walls are full height masonry, is there a good method to resist lateral load reactions without cross grain bending in the ledger and without casting something into the walls.
Also at the ledger for the second floor trusses, where the walls are full height masonry, is there a good method to resist lateral load reactions without cross grain bending in the ledger and without casting something into the walls.






RE: Depth of wood floor trusses
Such ledgers are usually bolted to grouted cells. Most codes say 6' oc - I like 4'
RE: Depth of wood floor trusses
http://www.ufpi.com/literature/ojbroch-187.pdf
Vibration criteria are presented in the Canadian Wood Design Manual and probably other sources.
BA
RE: Depth of wood floor trusses
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: Depth of wood floor trusses
Since it is a house with a 24' span I will assume you will have some interior hallways with walls, so there is your damping most likely. Deflection is a separate issue...
RE: Depth of wood floor trusses
It meets the deflection criteria of several codes. But I would NEVER spec a wooden floor truss at 30' only 16'' tall. It will be bouncy and almost impossible to "fix" or deaden.
RE: Depth of wood floor trusses
RE: Depth of wood floor trusses
1st floor walls are wood or CMU?
If wood, I'd avoid ledgers, bear on top of the wall if you can.
RE: Depth of wood floor trusses
Neither would I. I was a little surprised to see that they showed this as an option in my earlier reference. I like the rule of L/18 for wood trusses and might be tempted to go to L/12 as suggested by woodman88.
BA
RE: Depth of wood floor trusses
RE: Depth of wood floor trusses
Then the truss is nailed, bolted or "clipped" to the sill. Use a 2x6 sill if you want.
RE: Depth of wood floor trusses
That is the typical detail used locally for houses with masonry walls. NDS recommends no cross grain bending.
RE: Depth of wood floor trusses
Dik
RE: Depth of wood floor trusses
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RE: Depth of wood floor trusses
I know that will work but it is the type of thing that I am trying to avoid. Typically not done like that in the local market and you know how it goes when you try something different.
RE: Depth of wood floor trusses
BA
RE: Depth of wood floor trusses
Regarding the detail, anything else I'm coming up with is even more exotic and would involve odd sized ledgers, plate washers or weird truss connections.
Hmmm....lag bolt a clip (of some sort) into the ledger at the same line as the ledger bolts? Still exotic though.
Steel ledger an option?
RE: Depth of wood floor trusses
If you're dealing with a ledger for truss support, you're going to need bolts a lot closer than 4' o/c., they'll relate to the actual joist locations to take the vert. loads, and not be overloaded. Without seeing your actual detail it's tough to see exactly what the possibilities are, or the magnitude of the loads you're dealing with. There is probably a strap that you could wrap behind a ledger, bend horiz.; and nail to the T or B chord of the truss; locating these bolts properly w.r.t. the strap would have the bolts acting in pull-out/tension, with little cross grain bending. Maybe have the truss manuf'er. detail the truss end bearing so the last couple vert. chord members bear vertically on the ledger and allow the ledger to fit up in the truss depth. Then lag through the full depth vert. end chord members into the ledger if your loads are low enough for lag screw pull-out values.
Or just weld the damn thing onto the ledger and get on with it.
RE: Depth of wood floor trusses
RE: Depth of wood floor trusses
RE: Depth of wood floor trusses