"h" for chimneys, tanks, rooftop equipment & similar structures

[jeg1976]

Per ASCE 7-05, is "h" in Fig. 6-21 the height of the (rooftop) structure from the base of that (rooftop) structure (i.e. roof elevation of the main/supporting building) to the top of that (rooftop) structure (vs. from grade elevation)? All other "h" references (except for Fig. 6-21, e.g. Sec. 6.5.15.1) would be the mean roof height of the main/supporting building, right?

 

[TXStructural]

Well, the answer is "yes". These coefficients should be based on the geometry of the rooftop structure. The design wind velocity is adjusted for the overall height of the building. But not mentioned in this are any complicating issues, such as the shape of the building and how close to an edge the rooftop structure is.