ASCE MWFRS Directional Procedure Mean Roof Height

[Sanira]

Hi all,

I am working on a structure that has tow low roofs surrounding a middle gynasium which is a separate higher roof. The average height of low roof is 14' and that of higher roof is 21'.

While caculating the ASCE MWFRS wind load using directional method, what do you guys use as 'Mean Roof Height' for the purpose of determining external pressure coefficient 'Cp' and velocity pressure'qh' for leeward walls?

Thanks.

 

[phamENG]

In a case like this I break up each area into it's own "building". So you'd have one building with an average roof height of 21' - apply the pressures using this value to the associated walls. Then you'd have two more that are 14'- apply those pressures to those walls. The important thing is to remember how the load comes about and why it is higher/lower based on the various geometries. If you don't know those things, spend some time in the ASCE 7 commentary and papers/books on the subject of wind loads.