ASCE 7-16 C and C Wind Loads on Attached Canopies 30.11-1

[engreg]

I am designing a canopy and want to confirm I am using the updated codes correctly if any one has knowledge of the 7-16 code expansion. It seems pretty straight forward find the GCpn from the chart below (attached) and multiply it by the wall wind pressure. My canopy is low on the building falling within hc/he < 0.5, This gives me a canopy uplift and downward force of less then my wall pressure. My hesitation comes in when this value is compared to roof overhang values, which is what I used for canopies before ASCE 7-16, the overhang pressures are over 3-4x higher then the new canopy pressures, hoping someone can explain why this is, and that this is indeed how the code is supposed to be used. Its possible I am supposed to add the loads to the canopy twice, (once for each face, similar to a parapet), any help would be appreciated.

 

[SandwichEngine]

This article isn't from ASCE but has an example of how to calc the new canopy wind. They add pressure from one side to suction from the other side for the global canopy forces. For calculating just the suction on the top surface, for example, I would think you wouldn't use both loads at once.

https://www.mecaenterprises.com/wind-load-on-a-canopy/

 

[engreg]

Thanks, I have seen that article, and it backed up how my calcs are being run, its very low compared to roof over hangs. Secondly, the Chart using seperate valued for top on bottom member loading states it is using the highest possible values for hc/he, which seemed incredibly conservative, as always any insight is appreicated

 

[1.392DL]

For a canopy low on a wall you're going to have similar wall pressures top and bottom of the canopy. Thus, the differential is a lot less than a typical overhang for a roof rafter or truss. A typical overhang will have wind moving a lot faster over the top than below it, creating a very high net uplift. This is why your canopy force isn't nearly as high as your overhang force.