Car shed, Roof uplift 1

[S275]

Hi,
For car sheds similar to these:

http://www.polycongulf.com/Uploads/Product/26_Car-shed.jpg

http://upload.ecvv.com/upload/Product/20111/China_Car_Shed_Polycarbonate_Sheet20111211039457.jpg

There is possibility of having the wind load acting on the underside of the roof, causing uplift force.

I found this pdf file that contains some helpful information,

http://emergencymanagement.wi.gov/mitigation/docs/1432_final_report.pdf

I use BS and I didn't find any requirements for such case.

I need your opinions/help on these points:
1)Is there any specific requirements in any code/ standard you know?

2)What would be the suitable percentage of blowing wind to be considered as uplift force?

3)Any suggestions regarding the load cases and combinations?

Regards

 

[JAE]

I apologize in advance but I don't know anything about the British standards - but in the US, the document - ASCE 7 - is the source of loads for buildings. It does have open structure uplift values that you can calculate. I would think the British standards would have something similar.

Also - the wind uplift is treated in our load combinations as just part of the wind contribution.

 

[S275]

Thanks JAE

Referring back to EN 1991-1-4:2005, I found that they are addressing the free-standing canopies.

However, they are only providing the pressure coefficients for "monopitch" and "duopitch" but for curved roof they include it only for enclosed structures.

I think I will have to adopt the values of "duopitch canopies" for the case of curved roof???

Regards