I'm on the fence about which type of building to build.my main concern is the wind load.I live in hurricane alley here in lower Al. and I'm curious if anyone here has first hand experience as to which type of building has the best wind load in the real world scenario i.e. hurricanes,tornadoes vs. an engineers theoretical rating of a building type. It seems a pole barn would hold down better due to the poles being buried in the ground vs. a steel building being held down by bolts in concrete. Any input would be greatly appreciated and to help me decide because I really need a place for my stuff soon.
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Best for high wind load? Steel or pole barn?
- Thread starter wfopossum
- Start date
Shocker
Well-known member
I have read that many pole barns survived the big hurricanes.
akdiesel
Well-known member
I have not seen foundations pulled up from hurricanes or tornados. Now I live in a high wind location and have never delt with a tornado, but with that I think the biggest problem in this case is the ability of the wind to get under a structure (roof, ceiling, etc...) and create pressure below like the wings on a plane. If the roof is not secure to the structure than the building will fail, either lift or aid in tipping over.
The pole barns I have seen are attached with the same bolt concept as stick frame or metal framing. The bolts are set during the pour of the foundation or slab and then attached to the frame work via drilled holes in the sill plate or metal plates holding the timbers.
The pole barns I have seen are attached with the same bolt concept as stick frame or metal framing. The bolts are set during the pour of the foundation or slab and then attached to the frame work via drilled holes in the sill plate or metal plates holding the timbers.
jwith68
Well-known member
Either can be engineered for high wind loads, just depends on the design. As akdiesel pointed out, uplift resistance is paramount. Simply having a pole buried a few feet deep in the ground does not give it much uplift resistance.
Here's a link to a page of research papers and other publications by Dr. David Bohnhoff from the University of Wisconsin, who has done a lot of work with ag structures, particularly pole buildings. Lots of reading here, but a lot of good information to be had:
http://bse.wisc.edu/bohnhoff/publications.htm
Here's a link to a page of research papers and other publications by Dr. David Bohnhoff from the University of Wisconsin, who has done a lot of work with ag structures, particularly pole buildings. Lots of reading here, but a lot of good information to be had:
http://bse.wisc.edu/bohnhoff/publications.htm
I've read and heard about the uplift,all it takes is a small opening for the wind to pass through and lift the roof and the structural integrity of the whole building is compromised. So maybe roof attachment and windows,doors are just as or more important as foundation attachment when it comes to windload.
They used what he called 'hurricane clips' which are brackets that fasten the trusses to the header board to help keep them from lifting on mine. I don't know how high of wind they will withstand but we have had about 60 mph here no problem.
WNYflyer
Well-known member
Wood/Steel, both need to engineered. I would talk to a building supplier who does both steel and wood and tell them, your location, size of building, roof pitch and most importantly your eaves height. They should have a good feel for what eave heights a steel building might be better than a true "pole barn". Especially under hurricane winds.
Things to worry about:
Does the foundation system need to be engineered and stamped ? Talk to the local building officials on the basic requirements.
Flying debris and any damage it may do to the building and how easy that damage is repaired/replaced. May help you decide on the type of siding, roofing, windows, overhead doors, etc.
Number/spacing of fasteners attaching the siding and roofing to the structure. Most important at the exterior corners (wall/wall, wall/roof) of the building where localized wind loads are higher and can **** the siding/roofing off the structure. Any wind under your roof from siding and roofing tearing off is a bad thing.
Foundation is properly engineered and installed. Building is only as good as its foundation, especially a light weight building that wants to fly through the wind under hurricane winds. I suspect you will need the weight of a concrete foundation to hold the building down.
Things to worry about:
Does the foundation system need to be engineered and stamped ? Talk to the local building officials on the basic requirements.
Flying debris and any damage it may do to the building and how easy that damage is repaired/replaced. May help you decide on the type of siding, roofing, windows, overhead doors, etc.
Number/spacing of fasteners attaching the siding and roofing to the structure. Most important at the exterior corners (wall/wall, wall/roof) of the building where localized wind loads are higher and can **** the siding/roofing off the structure. Any wind under your roof from siding and roofing tearing off is a bad thing.
Foundation is properly engineered and installed. Building is only as good as its foundation, especially a light weight building that wants to fly through the wind under hurricane winds. I suspect you will need the weight of a concrete foundation to hold the building down.
I agree either building can be designed for high winds. Mine had to be rated at 100mph for the trusses and used clips as mentioned to keep the roof form blowing off. What wind speeds do the buildings in your area need to designed to withstand. I don't think many pole building actually uproot completely, usually the metal goes and then the framing. If I lived near to the coast I would eliminate overhangs(or reduce ) to keep wind profile down regardless of type.
Tscott
Well-known member
Properly engineered either will be just fine. I will say that as far as uplift goes, I think a steel building will perform better than a standard dirt floor pole barn. The anchor bolts I used in my Steel building were about 12" long and had a bolt and a washer threaded on the bottom. The only way they are coming up is if the concrete cracks and comes with them. I have heard of the standard "L" bolts actually being pulled out without without destroying the concrete under very High loading. Kind of like pulling a tring through a pipe.
The pole barns I have built to engineered plans called for a piece of rebar to be inserted through the pole before concrete is poured. This will effectively prevent the pole from simply slipping out out of it's foundation.
Tom
The pole barns I have built to engineered plans called for a piece of rebar to be inserted through the pole before concrete is poured. This will effectively prevent the pole from simply slipping out out of it's foundation.
Tom
buening
Well-known member
The IBC/ASCE7 codes have wind charts and the engineer will likely choose the corresponding wind speed according to your location. If you want it to be designed for higher wind speeds, I would recommend mentioning this prior to having it designed. It may add a bit more construction cost though.
I'll add a side note...
Whichever building you decide to build, recognize that the doors are often one of the weakest links on the building.
Obviously, if the doors are open (and facing the wind), wind resistance goes out the window. But even if the doors are closed, wind can be an issue. Rollup doors are one thing, but many pole buildings have large sliding doors. Here's the benefit of my experience with the sliders:
If the wind is blowing directly at the doors, you need to make sure you have a very sturdy bottom center post that the doors securely attach to. It also works well to have a concrete 'step', about 1" high, running the length of the doors that backs them up (so when the wind blows, it blows them back into the concrete, instead of putting all of the tension on the center post).
If the wind is blowing across the doors (laterally), then securing the outside edges of the doors is critical. Make sure you have a sturdy, mechanical link that ties the two doors together in the middle (when closed) and a secure mechanism to hold the outside edges of the doors tight to the building (again, when closed). Do not rely on the tracks to do all of the work! If possible, spec top and bottom tracks (instead of top only). And KEEP THE DOORS SECURELY LATCHED WHEN NOT OPEN!
Whichever building you decide to build, recognize that the doors are often one of the weakest links on the building.
Obviously, if the doors are open (and facing the wind), wind resistance goes out the window. But even if the doors are closed, wind can be an issue. Rollup doors are one thing, but many pole buildings have large sliding doors. Here's the benefit of my experience with the sliders:
If the wind is blowing directly at the doors, you need to make sure you have a very sturdy bottom center post that the doors securely attach to. It also works well to have a concrete 'step', about 1" high, running the length of the doors that backs them up (so when the wind blows, it blows them back into the concrete, instead of putting all of the tension on the center post).
If the wind is blowing across the doors (laterally), then securing the outside edges of the doors is critical. Make sure you have a sturdy, mechanical link that ties the two doors together in the middle (when closed) and a secure mechanism to hold the outside edges of the doors tight to the building (again, when closed). Do not rely on the tracks to do all of the work! If possible, spec top and bottom tracks (instead of top only). And KEEP THE DOORS SECURELY LATCHED WHEN NOT OPEN!