WIND LOAD CALCULATION

[engineeringofcivil]

HOW TO CALCULATE WIND LOAD WHICH HAS GOT CLADDING ON ALL SIDES BUT NO ROOF. ROOF IS OPEN

 

[ilyas415]

Why are you using all caps?

The answer depends on a number of different factors.

1). Are you trying to calculate overall structural wind loading? Or wind loading on individual cladding panels?

2). What type of structure is it? Tall building? Shell-like structure?

3). If you have some sketches, pictures or descriptions of the structure, please share.

Help us to help you!
Ilyas

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Ilyas

 

[engineeringofcivil]

This is is a structure in which Air cooled condensers are housed.A rectangular structure having cladding in all four sides, but the roof is open. It is like structural shed of 72m length,29m width and 11.7m ht (without roof covering ). We have to design the shed structure, so wind pressure has to be calculated . The structure will be designed using STAAD

We have checked, IS 875, ASCE 7 ,but unable to find the exact pressure co-efficient.
Please help.

 

[BridgeSmith]

If it has walls but no roof, it's not a building, it's solid-fenced enclosure. Are there coefficients for fenced enclosures? If so, that would seem to be the correct structure type to consider the loading for.

Rod Smith, P.E.

 

[dauwerda]

I would be inclined to use section 29.4 of ASCE 7-10 for wind pressure on Freestanding Walls and Solid Freestanding Signs.

 

[engineeringofcivil]

Dear Rod,
Yes the structure is like fenced enclosures without roof. Unable to find any reference towards calculating the pressure coefficient, to calculate the exact wind load. Can we do with 1P and forget about any internal pressure.

Dear dauwerda,
I think the structure is not similar to freestanding walls and solid freestanding signs.Any other suggestion , please.

 

[ilyas415]

Dauwerda is right... the closest idealisation based on your description are freestanding walls/parapets.

@engineeringofcivil - what does 1P mean? D you mean taking the pressure coefficient at 1.0*roof height dynamic pressure? This approach would be wrong.

If the wall connects to the floor, then you take s/h = 1...

The net force based on your wall aspect ratios will be around 1.3 to 1.45.

To put this into context, if you had a building and considered no internal pressure, the windward and leeward pressure coefficients would AROUND +0.8 and -0.5, respectively. Therefore force coefficient would be 0.8-(-0.5) = 1.3 (similar to the free standing wall case).

So it is perfectly reasonable to use pressure/force coefficients for freestanding walls, especially given that you likely do not have significant blockage directly behind your walls (do you have any architectural visualisations of your building?).

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Ilyas

 

[BridgeSmith]

I do bridge design, engineeringofcivil, so I'm really only familiar with the AASHTO code. I can't help you with what the proper section of your governing code would be. I was just making an observation on the functional type of the structure, hoping that it might give you some ideas of where to look. It appears dauwerda and ilyas415 have been able to help with the specifics from the ASCE.

Rod Smith, P.E.

 

[msquared48]

If this is on a rooftop, there is a wind speed-up factor to add in here too - and not Kzt. Kinda hidden in ASCE 7.

Had to use it in the past for rooftop applications in the past for rooftop telecom enclosures.

Mike McCann, PE, SE (WA, HI)

 

[Ron]

Agree with Mike. You need to consider the rooftop application and consider it a screen wall....use the fence/sign application as HotRod10 noted. They are in ASCE 7.


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