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(OP)
I require some assistance. I am designing an overhead protection canopy for a construction site in Ft Lauderdale, FL. I have done many of these in the past and have used ASCE 7-98 to calculate the wind loads on it. No problem there. However, I have a customer who requires the design to be checked off by Floida D.O.T. which requires the use of ASCE 7-05. Here is where my problem arises. The canopy is an open structure with a flat roof. It is 5' wide and 100' long and about 9' high. It is a temporary structure that is to be anchored to the foundation to resist wind loads. In 7-98, table 6-9 gives the Cf values for different monoslope roof dimension ratios between 5 and 1/5 for all heights. No problem figuring it there. However, 7-05 changed to a new figure, figure 6-18A, which gives values for Cn for different roof angles only. At the top of the figure there is a limitation for h/L to be between 0.25 and 1.0. My h/L is 0.09 or 1.8 depending on the wind direction. Can someone explain to me how to calculate the wind loads for this canopy using 7-05 or maybe explain to me how I can use this chart for my design?

Take a look at Fig. 6-18D and, in particular, Note 5: this addresses case of monoslope roof @ 0 degrees with h/L between 0.05 and 0.25. ...May also want to check out applicable errata: http://content.seinstitute.org/pdf/erratasheet7-05.pdf for some corrections/clarifications.

I'm not sure about when h/L is greater than 1.0 but I would probably look at the relevant references mentioned in the Commentary: see discussion for Fig 1-18 and C.6.5.13.

(OP)
This is great, except my value for the wind across the structure. This canopy is 5' wide and 10' tall. It runs about 100' along the sidewalk. There is a barrier wall along the construction side of the canopy roughly 2' away. Therefore, I have unobstructed wind flow when wind blows along the 100' direction and obstructed wind flow when the wind blows in the 5' direction. My h/L value for the first case is 0.1 and the h/L value for the second case is 2.0. I can use the figure 6-18D for the first case, but not the second. Any more ideas? Should I just revert back to 7-98 where I can actually figure the values, since 7-05 doesn't seem to work? Please help ladies and gentlemen.

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