Wind load on canopies at ground floor (cantilevered glass canopy supported on first floor concrete slab) for building height > 18meter

[SHAFEEH]

1. I have a glass canopy with steel structure which is fixed to the first floor slab of the building. The total building height is more than 100meter. But the canopy height from the ground is 5m only.
How can i get the net pressure coefficients for the canopy in this case? ASCE-7 provides provisions for buildings with h<18 meter. But in my case h is greater than 100meter. Why the code does not have the provision for this case?

2. Coefficients for overhang of the roof is what you guys consider in the above case? But even that case is limited to h<18 meter. There is no overhang coefficients for h> 18 m (correct me if i am wrong. I believe so).
Also if we are following the overhang coefficients , what height will you consider to determine velocity pressure? The roof height or the canopy height from ground? It seems like the code says roof height as the figure is for roof overhangs. (Again correct me if i am wrong ) but this does not seem logical for lower canopies !! Same wind loads on canopies at ground floor and canopies at 50th floor ????? Can i use the height of canopy only?



Thanks in advance !!!!

 

[ANE91]

Your condition is addressed in ASCE 7-22. See 30.9; specifically, see Figures 30.9-2A-B. Unlikely that this load is significant enough to warrant an MWFRS analysis. (Definitions in 26.2 support this notion.) I have no doubt that your building official will allow use of this code for your condition.

These provisions are built on wind-tunnel testing, sometimes unvalidated, so the wind design provisions in previous code cycles were still being fleshed out. It's only gonna get worse...

 

[SHAFEEH]

Your condition is addressed in ASCE 7-22. See 30.9; specifically, see Figures 30.9-2A-B. Unlikely that this load is significant enough to warrant an MWFRS analysis. (Definitions in 26.2 support this notion.) I have no doubt that your building official will allow use of this code for your condition.

These provisions are built on wind-tunnel testing, sometimes unvalidated, so the wind design provisions in previous code cycles were still being fleshed out. It's only gonna get worse...

Thank you for that . I was referring to ASCE - 7-16 only where the coefficients was given for h<18m only. thank you.

One more thing. There are two separate figures 30.9-2A & 2B for forces individually on top & bottom surfaces and the other for combined forces.
Do we have to consider both on different load cases? or can i use figure B only considering combined action from both surfaces?
or do we have to follow figure A also by assuming that the load is acting on one surface only at a time?

My case is a glass canopy, top and bottom surface means top and bottom of glass. Supporting structure is same for both loadings(top or bottom).

 

[ANE91]

 

[SHAFEEH]

Perfect.
Thank you very much.
It was an Eye opener to always be updated with the latest version.