Arup presenting on wind engineering: Showing photo's of wind damage where the building itself was soliid until panel/window/roof was damaged then the pressure differentials tore the rest of the building to pieces.
We were mainly looking at wind and its effects on tall buildings, so I don't have much to add...
my fiancee's family has a beach house on the gulf of mexico. there seems to be two trains of thought in construction down there. the first is to put the building on stilts to prevent the house from being flooded (not your problem). the second is to have a very low house that hides in the dunes. their beach house is an old house that subscribes to the second method. ivan was the only hurricane to take its shot at it and leave with a piece of the roof. 32' feet to peak may not sound all that high, but when it's exposed to a strong wind that's a lot of surface area resisting the force. this probably isn't the answer you're looking for, but i think the actual shape and volume of the structure is probably the best preventative for wind damage (as is of course its siting).
otherwise, 2x6s with 15" anchor bolts and additional shear panels sounds about right.
actually, another feature of the house is that it is oriented towards the beach, but it is very deep. there are two interior walls that run the entire depth of the house. they are bearing walls that allow an extra wide main living area, but they are also acting as major shear walls and bear much of the horizontal wind load off the gulf. it's interesting how the interior walls supplement the exterior to provide support for the unusual structural forces under strong wind conditions. i don't know if that was just a coincidence in the design or not, but more than stud size or bracing, i think it goes a long way in explaining why it's been so hurricane resistant.
That said we have done a number of coastal projects that are Exposure D and within 120 and 140mph zones. Corners take the highest loads and your engineer will use the term "continuous load path" often so a bit of reading up on those 2 concepts on your part will make you seem knowledgeable and capable on having a dialog on aesthetics vs. structure. I would also recommend understanding the installation of Simpson's hurricane clips - we had a project a few years ago that the contractor installed them *after* the sheathing using the standard nails - not allowed...
Much of the engineering solution will depend on the architectural design and how many opportunities for sheer walls there are. If there is not a lot of glass and if there are a lot of interior walls the engineer will be happy. But (more likely) if you have large expanses of glass that are within 4 feet of the corners and large, open interior spaces sheer wall solutions will be more complex and could involve steel/steel bracing.
If you are in a coastal V-Zone or A-Zone the structure will need to be designed to resist buoyancy and hydrodynamic forces as well. Additionally, check to see if you need to have hurricane rated glazing and assemblies or if the structure can be designed as "partially open" meaning it was designed to have the envelope breached and the structure is capable of resisting the internal forces.
danver actually hiring a structural engineer to take a look at the project. In the mean time I'm reviewing the document "120 mph
exposure B guide" Wood Frame Constuction Manual prepared for
the American Forest And Paper Association American Wood Council.
Take a look at (new) super tall skyscraper floorplates, they vary in plan with height, and do not offer flat facades or full-on right angles - the corners are broken out to reduce the vortex shedding and drag. Same goes for the roof which generally tapers to a spire for the same reasons. As it's a short building, and rare winds, you needn't worry about downdraught...
They're serious about that stuff. This happened in only 90 mph. A lot of people were pretty torn up by all this. It was in an old Taco Bell building. All the other ones around town have pretty much been torn down as a result. Pretty big lawsuits filed in the past 6 months.
By the way, despite what that article says, there wasn't a damn thing unclear about it. 90 mph winds picked up the roof and the pressure changed sucked it back down. The whole building collapsed and it killed a girl who was just trying to eat some chicken fried rice. I drove by about 3 or 4 minutes later on my way to get some pizza. You wanna talk about f-ed up...
I have also been reviewing the Simpson Catalog which deals with high winds. It has been an interesting read. So I think I have most
every thing covered so the Structural Engineer doesn't bleed all over my drawings. I know I'm going to have a good sit down with him and
let my brain be a sponge. This is the kind of information one never gets in school....least it was low on the priorty list when I was in school...but now I'm and old fat santa....so hopefully things have changed.
wfcm 120mph winds
Does anyone have any insight regarding Wood Frame Construction to withstand 120 mph winds?
simpson ties/brackets
ya right....how about 15" long anchor bolts...
2x12 studs.
anchor bolts wont do jack if the house starts to rack/twist.....
prolly alot of cross bracing in the attic and upper corners of the walls
b
Are you in Wind Exposure Category D? (as defined by IBC)
Wind Caategory B
what sort of insight do you need?
keep it low, compact and provide regularly spaced and lengthy shear panels.
How tall is this building?
Gable roof 8 and 12 pitch......32' to peak
Two story structure.
trussed space over second floor.
Category B, and you're designing for 120 MPH winds? What characteristic(s) of your site bump you up into such a high wind speed?
I know the solution: ask your engineer.
Arup presenting on wind engineering: Showing photo's of wind damage where the building itself was soliid until panel/window/roof was damaged then the pressure differentials tore the rest of the building to pieces.
We were mainly looking at wind and its effects on tall buildings, so I don't have much to add...
my fiancee's family has a beach house on the gulf of mexico. there seems to be two trains of thought in construction down there. the first is to put the building on stilts to prevent the house from being flooded (not your problem). the second is to have a very low house that hides in the dunes. their beach house is an old house that subscribes to the second method. ivan was the only hurricane to take its shot at it and leave with a piece of the roof. 32' feet to peak may not sound all that high, but when it's exposed to a strong wind that's a lot of surface area resisting the force. this probably isn't the answer you're looking for, but i think the actual shape and volume of the structure is probably the best preventative for wind damage (as is of course its siting).
otherwise, 2x6s with 15" anchor bolts and additional shear panels sounds about right.
actually, another feature of the house is that it is oriented towards the beach, but it is very deep. there are two interior walls that run the entire depth of the house. they are bearing walls that allow an extra wide main living area, but they are also acting as major shear walls and bear much of the horizontal wind load off the gulf. it's interesting how the interior walls supplement the exterior to provide support for the unusual structural forces under strong wind conditions. i don't know if that was just a coincidence in the design or not, but more than stud size or bracing, i think it goes a long way in explaining why it's been so hurricane resistant.
Hire a structural engineer.
That said we have done a number of coastal projects that are Exposure D and within 120 and 140mph zones. Corners take the highest loads and your engineer will use the term "continuous load path" often so a bit of reading up on those 2 concepts on your part will make you seem knowledgeable and capable on having a dialog on aesthetics vs. structure. I would also recommend understanding the installation of Simpson's hurricane clips - we had a project a few years ago that the contractor installed them *after* the sheathing using the standard nails - not allowed...
Much of the engineering solution will depend on the architectural design and how many opportunities for sheer walls there are. If there is not a lot of glass and if there are a lot of interior walls the engineer will be happy. But (more likely) if you have large expanses of glass that are within 4 feet of the corners and large, open interior spaces sheer wall solutions will be more complex and could involve steel/steel bracing.
If you are in a coastal V-Zone or A-Zone the structure will need to be designed to resist buoyancy and hydrodynamic forces as well. Additionally, check to see if you need to have hurricane rated glazing and assemblies or if the structure can be designed as "partially open" meaning it was designed to have the envelope breached and the structure is capable of resisting the internal forces.
Don't let the structural requirements hinder your design though. Here is a project that is Exposure D 120mph and here is one that is Exposure D 140mph.
danver actually hiring a structural engineer to take a look at the project. In the mean time I'm reviewing the document "120 mph
exposure B guide" Wood Frame Constuction Manual prepared for
the American Forest And Paper Association American Wood Council.
It has been an interesting read so far.
Take a look at (new) super tall skyscraper floorplates, they vary in plan with height, and do not offer flat facades or full-on right angles - the corners are broken out to reduce the vortex shedding and drag. Same goes for the roof which generally tapers to a spire for the same reasons. As it's a short building, and rare winds, you needn't worry about downdraught...
They're serious about that stuff. This happened in only 90 mph. A lot of people were pretty torn up by all this. It was in an old Taco Bell building. All the other ones around town have pretty much been torn down as a result. Pretty big lawsuits filed in the past 6 months.
By the way, despite what that article says, there wasn't a damn thing unclear about it. 90 mph winds picked up the roof and the pressure changed sucked it back down. The whole building collapsed and it killed a girl who was just trying to eat some chicken fried rice. I drove by about 3 or 4 minutes later on my way to get some pizza. You wanna talk about f-ed up...
I have also been reviewing the Simpson Catalog which deals with high winds. It has been an interesting read. So I think I have most
every thing covered so the Structural Engineer doesn't bleed all over my drawings. I know I'm going to have a good sit down with him and
let my brain be a sponge. This is the kind of information one never gets in school....least it was low on the priorty list when I was in school...but now I'm and old fat santa....so hopefully things have changed.
share with us what you learned, snooker. we're waiting with bated breath.
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