Is there a general truss span width where wood no longer makes sense and its time to look at steel?
Truss Span - When to go from wood to steel?
Spencer
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My brother used to travel and set light gauge aluminum trusses.
He said they are engineered to the max though
He said they are engineered to the max though
I'm asking from the perspective of large shops. I see some pretty big shops go up around here for farmers that seem to push the limits of wood buildings.
There is one going up down the road from me, 90 x 140, 18' to the square.
No, there is no general rule. AG buildings tend to use the largest wood truss clear spans because they're relatively inexpensive. 2X6 members will get you up around 50' pretty easily for many load situations. The longest spans tend to be used in AG areas with relatively low snow loads.
From what I've seen, people tend to go all wood or all steel for an AG building.
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For residential non-habitable storage that can be used for a shop, a wooden post steel truss pole barn is way cheaper than wood trusses on 2' centers. You can get them on 12' centers with buckets welded on top to carry rafters 12' standing upright. Like this...
![Image]()
We've done 66' trusses but with four point bearing systems. These steel trusses can span 50 to 60' with nothing in the centers.
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We've done 66' trusses but with four point bearing systems. These steel trusses can span 50 to 60' with nothing in the centers.
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You could get a permit for power water and maybe a toilet but would never get approval for a kitchen... get it. Lol perfect for a shop
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I should also say, the 50' plus wood had other bearing points for them as well.
The trusses in this home I framed were just under 50' free span.
http://www.contractortalk.com/f14/4-5k-single-fam-build-238738/
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I did a small 45' airplane hanger with wood. 50psf snow load area. Truss guy said it was no problem.
60' clear span, your choice of pitch:
http://www.public.iastate.edu/~mwps_dis/mwps_web/plans/truss_60.pdf
http://www.public.iastate.edu/~mwps_dis/mwps_web/plans/truss_60.pdf
Thanks for the info, I hadn't seen the combination before.:thumbsup:For residential non-habitable storage that can be used for a shop, a wooden post steel truss pole barn is way cheaper than wood trusses on 2' centers. You can get them on 12' centers with buckets welded on top to carry rafters 12' standing upright. Like this...![Image]()
We've done 66' trusses but with four point bearing systems. These steel trusses can span 50 to 60' with nothing in the centers.
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AN outdated reference:
MWPS9, Designs for Glued Trusses
Price: $14.00
Criteria for selection, construction, and erection of glued trusses are found here. Designs for 9,004 plywood-gusset wood trusses are featured.
Also featured are 78 truss selection tables, with data for trusses with 20-feet to 60-feet spans; 3/12-, 4/12-, and 5/12-slopes; 2 feet-, 4 feet-, and 8 feet-spacings; 0-, 5-, and 8-psf ceilings; roof loads from 12- to 100-psf; and lumber grades of 1,100f, 1,400f, and 1,600f. Maximum allowable roof loads are given for each truss design.
http://extension.missouri.edu/p/MWPS9#Pages
MWPS9, Designs for Glued Trusses
Price: $14.00
Criteria for selection, construction, and erection of glued trusses are found here. Designs for 9,004 plywood-gusset wood trusses are featured.
Also featured are 78 truss selection tables, with data for trusses with 20-feet to 60-feet spans; 3/12-, 4/12-, and 5/12-slopes; 2 feet-, 4 feet-, and 8 feet-spacings; 0-, 5-, and 8-psf ceilings; roof loads from 12- to 100-psf; and lumber grades of 1,100f, 1,400f, and 1,600f. Maximum allowable roof loads are given for each truss design.
http://extension.missouri.edu/p/MWPS9#Pages
If you want to play with designs there's medeek's truss calculator on this thread:
http://www.contractortalk.com/f116/truss-calculator-137019/index3/
http://www.contractortalk.com/f116/truss-calculator-137019/index3/
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We've got the eagle plate program. I'll run that tomorrow to just let you know. Bet it's 2x6 chords. Or larger.
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I forgot I had put the program on my laptop too along with the deck top at work. I pulled my lap top out but it has expired. They send a reset password every few months so you have to be a purchaser of their product to receive the security pin. You quit buying they expire your access to their programs. Yeah it'll have to wait till tomorrow. I got all excited for a second. Guess it'll be tomorrow.
IF it works I hope I never get a job like that. I can only imagine setting those monsters. Two point bearing. Imagine all the bracing...
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IF it works I hope I never get a job like that. I can only imagine setting those monsters. Two point bearing. Imagine all the bracing...
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And Builders Inc has brought in another option. I think the only way you're going to get a hard answer for your area is do a bunch of pricing work with suppliers. Joasis could probably give you an idea about how things work out in his area for sure for all steel vs all wood. Then there is the conventional framing or pole framing.
Farmers tend to be very cost conscious. If there are some big farms with big buildings in your area, I'd check them out and ask questions (if you don't mind knocking on doors).
That's all I have....
Reminds me of way back when I was working on the AF base. They had pole barn buildings roughly 40x100. The old timer that worked in the office told me he and others hand nailed all the trusses themselves for the buildings. All plywood gussets. The civil engineer designed them in house.
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