Wind allowances for workshops and large buildings 2

[Aussie Dave]

I am currently working on a large workshop with two roller door openings either end of the building; this workshop is located in England East Anglia. Does anyone have guidance on appropriate wind allowances for large workshops and buildings, I think a figure of 1.5KN/m^2 can be used?

 

[Agent666]

You have to work out the basic wind load and hence pressure from Eurocode codes. This will be modified by pressure coefficients depending on what you are analysing or checking.

You can't just guess a load. It will be site specific.

 

[dhengr]

Aussie Dave:
Shouldn’t they be treated like any other building or structure, or does the wind somehow avoid them? In your case, you might have an open structure or a fully enclosed structure depending upon the condition of the O.H. doors. Although, it does seem that many farm bldgs. and country outbuildings are not really designed for adequate wind loads. Then, the roof often comes down to rest on top of the combine, tractor or hay bails stored in the bldg. when there is a fairly strong breeze.

 

[NOLAscience]

Are you trying to engineer the building or are you just looking for a guideline so that you order the right door for the building?

 

[Aussie Dave]

I am aware of the four stages of calculating wind actions on buildings following BS EN 1991-1-4 and its National Annex;
Calculation of the peak velocity pressure
Calculation of the structural factor
Determination of external and internal pressure coefficients
Calculation of wind forces
My problem is that there is an existing workshop with large roller doors either end of the workshop, and I have been asked to provide a wind post because an external wall 2.4m by 6m long has movement issues. I am concerned with the wind acting against the outside wall and the suction on the inside of the wall, because of large roller doors being open 70% of the time. This is why I am asking the engineering community if there are any other higher wind factors to consider for this scenario. Otherwise, I will follow the standards according to BS EN 1991-1-4 and National Annex.

 

[kieran1]

Your on the right track.

The doors being open will create a negative internal pressure co-efficient. Combined with the external pressure will give you the lateral load.
1.5KN/m2 would not be unreasonable for 2.4m high wall panel of structure with dominant openings.
When checking the capacity of the wall you can reduce the load factor if the wall is not critical for stability of the structure.

Kieran

 

[Agent666]

That info should have been in your original post I guess.

Realistically when you get a serviceability wind event it correlates to a fairly significant wind speed. Such that most cases you'd imagine its all closed up due to the weather that's going on at the time. Not withstanding this, if its open then you've got dominant openings. In many code this can mean that internal pressure coefficients can equal external coefficients, so there's potential to almost doubling the loads on an element. I assume Eurocodes address this concept.

If you're seeing some concerning movement in day to day use then it's probably under significantly lower than serviceability loading, or there's something wrong with the load paths involved that may have not been anticipated during the original design.

Since you are fixing an issue no one's going to complain if you take a conservative approach, the materials for a one off fix are such a small percentage of the costs. Last thing you want is the issue still to persist after the fix.