Tall Free Standing Sign Near Building - Parapet Loading?

[MJB315]

I have an 18' tall free standing sign (approx. 16' wide) being placed near (about 1' - 5' away) an existing building (about 14' tall). At what point does the free standing sign start to attract parapet type wind loads? Does ASCE provide any guidance?

"We shape our buildings, thereafter they shape us." -WSC

 

[ron9876]

At that location I would check to see if parapet loading controls.

 

[DST148]

Given the close proximity of the two structures, there would be reduction in the wind loads on the new sign structure. However, ASCE-7 does not permit reduction in wind loads due to apparent shielding by building and other structures.
Just because the free standing sign structure projects above the existing structure, the provisions for wind pressures on the parapet would not be applicable even if these pressures are higher. The wind pressures on a parapet are a combination of wall and roof pressures.
So long as you conform to all the provisions for a freestanding sign structure, you should be O.K. Given the flexibility of these sign structures, the gust effect factor G would require due consideration.

 

[asixth]

This sounds like a freestanding sign to me. I would be applying 1.5 pressure coefficient. That proximity and size would pose a hazard to the adjacent building during the ultimate wind event.