Wind Load Inside The Building 1

[BSVBD]

What wind loads do you use inside a building?

For a typical office building, I will use 5 PSF lateral load.

In a repair garage for large trucks or buses or any facility with multiple OH doors I feel I should increase the lateral to 7 or even 10 PSF.

Any thoughts?

Thank you!

 

[MacGruber22]

Are you following ASCE-7?

"It is imperative Cunth doesn't get his hands on those codes."

 

[racookpe1978]

The wind load on one side of a building (two sides really, at a corner or the like) will push the walls "over" from the outside, the wind whipping through an open set of doors will cause local high loads (on the door rails, door lifting or jamming forces, bottom of a partially-closed door, and the ground area near the opening), but wind forces are proportional to the cube of velocity, so they die rapidly down with the swirls once inside. Both walls (upstream and downstream) need to face the same forces when the wind is reversed later, so you don't really gain anything in strength required.

 

[BSVBD]

[Mac] I use an old-school "simplified" form of the simplified procedure using the wind pressures of figure 6-2 and apply them to the surface areas.

Other than through the analytical procedure, I don't recall seeing any reference to internal wind forces in ASCE-7.

 

[MacGruber22]

BSVBD -

5 psf is the code-mandated minimum working pressure.

You have first classify your building as open, closed, or partial, right? I very much doubt that you have an open or even partially open building - it takes a lot of wall area to be missing in order to have either partial or open. If you have a partially open or closed building, you end up with two pressure coefficients (internal GCpi and external GCp). Internal is for just that - surfaces internal to the building shell.

Partially-enclosed buildings have higher internal pressure coefficients - so, if you want to be conservative for interior pressures, GCpi for partial is the way to go.

"It is imperative Cunth doesn't get his hands on those codes."

 

[MacGruber22]

The attached is really the generally intent of the partially-open classification. It is very hard to find a building which meets this. Although thought to be by many, warehouses (and the like) are usually not suspect for being partially-open.

"It is imperative Cunth doesn't get his hands on those codes."

 

[BSVBD]

[Mac] Thank you for your extended effort and assistance.

 

[MacGruber22]

Sure thing. I doubt there is any reason to use anything more than 5 psf for a repair shop. 7 psf internal pressure would correspond to 46 psf basic wind pressure (7 psf / 0.15 GCpi). That would require a very tall single-story repair shop in conjunction with exposure greater than B.

"It is imperative Cunth doesn't get his hands on those codes."

 

[BSVBD]

I doubt there is any reason to use anything more than 5 psf for a repair shop

I don't recall where I found the recommendation for 7 psf or even 10 psf. I don't think it was in this forum, rather through internet research.

But, considering some of the concepts of [recookpe]'s post, when I consider a building that has multiple O.H. doors on opposing parallel sides of a metal building, for one, how can we NOT consider this an open building or partially enclosed? With such a building and so many openings and repetitive, obstacle door jambs, I consider the wind creating some increased conditions on the inside of that building.

Wind is not one of my forte's, so, please bear with me as I am still learning. My supervisor and I are still not convinced (fully) that our adoption of IBC back in 2002 was of absolute necessity for the scope of low-rise buildings we typically deal with. But, we certainly do conform when and wherever necessary. We do believe in safety.

 

[MacGruber22]

Definitions as per ASCE-7:

Building, Enclosed. A building that does not comply with the requirements for open or partially enclosed building.

Building, Open. A building having each wall at least 80% open.

Building, Partially Enclosed. A building that complies with both of the following conditions:
1. the total area of openings in a wall that receives positive external pressure exceeds the sum of the areas of openings in the balance of the building envelope (walls and roof) by more than 10%, and
2. the total area of openings in a wall that receives positive external pressure exceeds 4 ft2 (0.37 m2) or 1% of the area of that wall, whichever is smaller, and the percentage of openings in the balance of the building envelope does not exceed 20%.



"It is imperative Cunth doesn't get his hands on those codes."