Pole Barn Lateral Bracing
Pole Barn Lateral Bracing
(OP)
approx. 60'x128' pole barn.
No shear walls.
Exposed fastener metal roof and siding.
Each frame in short direction receives full lateral wind load based on tributary area.
The endwall posts (6x6) have moved significantly under approx. 60 mph winds (see pics).
Please share detailing information on lateral bracing of endwall posts. My thought is that endwall posts are not adequately braced at top based on photographs.
Please share comments, thoughts, smart remarks :)
Additionally, if you have a copy of Post-Frame Building Design Manual, National Frame Builders Association can you please share?
No shear walls.
Exposed fastener metal roof and siding.
Each frame in short direction receives full lateral wind load based on tributary area.
The endwall posts (6x6) have moved significantly under approx. 60 mph winds (see pics).
Please share detailing information on lateral bracing of endwall posts. My thought is that endwall posts are not adequately braced at top based on photographs.
Please share comments, thoughts, smart remarks :)
Additionally, if you have a copy of Post-Frame Building Design Manual, National Frame Builders Association can you please share?






RE: Pole Barn Lateral Bracing
The endwall 6x6's needed kickers back to the roof and a substantial roof diaphragm using structural sheathing for a building this size.
If I were you, I would strip off the metal sheathing on the roof and appropriate side walls, add structural sheathing on the roof, and create plywood shearwalls, in addition to adding kickers at the end walls.
The 6X6's look small for what looks like a 12 to 14 foot eave with the bay spacing seen.
I'll step down now, but this kind of crap makes me mad.
Mike McCann
MMC Engineering
RE: Pole Barn Lateral Bracing
And a general question for the gallery: should the bottom chord's of those trusses be braced to each other?
RE: Pole Barn Lateral Bracing
Mike McCann
MMC Engineering
RE: Pole Barn Lateral Bracing
The posts and girts will likely need to be beefed up and the trusses should be checked for wind and gravity load. Trusses will require additional bracing, particularly for uplift.
Nice looking boats, though.
BA
RE: Pole Barn Lateral Bracing
RE: Pole Barn Lateral Bracing
BA
RE: Pole Barn Lateral Bracing
RE: Pole Barn Lateral Bracing
The problem we've found is that the pole barns typically do NOT meet the IBC or the standard load/stress requirements of the materials. In other words, we could never get them to "work". Thus we told them we couldn't sign their design.
RE: Pole Barn Lateral Bracing
With light gauge siding like this they assume some of the load is carried by the siding and some by the posts.
http://www.nfba.org/Resources/content/dafi.html
NFBA took down their design manual because I can't seem to find it anywhere :\.
I'm trying to wrap my head around why it failed in the direction where it should be the strongest against wind. It looks as if the roof diaphragm had no way to transmit the load to the top of the long shear walls. So the force went to the top of the columns at the end walls and the connection wasn't sufficient.
RE: Pole Barn Lateral Bracing
What is the design wind speed for the area? Got to be greater than 60...
Mike McCann
MMC Engineering
RE: Pole Barn Lateral Bracing
I don't see a problem relying on the light gauge it if its used right, and they test actual wall assemblies to determine its capacity which I think is pretty accurate test. But a 128 foot long structure with no interior shear walls is pretty ridiculous to only rely on light gauge metal.
It's hard to tell from the picture but I just don't see where the wind load in the roof diaphragm can be transmitted to the top of the 128' long shear walls. Obviously in the short direction the gable end truss is able to take it to the top of the wall.
And from the 2003 IBC the lowest wind speed I see is 85 mph. Maybe he meant the damage was done after a 60mph wind storm?
RE: Pole Barn Lateral Bracing
RE: Pole Barn Lateral Bracing
I think something else is going on--I don't blame the steel roofing/siding.
DaveAtkins
RE: Pole Barn Lateral Bracing
ASABE EP486 "Shallow Post Foundation Design"
Here are a couple of references to start with. The only way to brace the top of the end wall is through a ceiling/roof diaphragm or bottom cord lateral and diagonal bracing. My guess is the loads are such that you couldn't get enough fasteners into the bracing members. Its appears pretty likely this is not an engineered structure. I doubt this structure could be retrofitted as a pole building. My guess is a shear walls and ceiling/roof diaphragm will be more economical.
RE: Pole Barn Lateral Bracing
RE: Pole Barn Lateral Bracing
EIT
www.HowToEngineer.com