Seismic Design of a Roof truss

[LJ_]

Hello!

I am confused as in what chapter I should use for seismic design of roof trusses in ASCE 7. I think it should chapter 13 or 15 because the roof is a thing of its own. What do you think?

 

[canwesteng]

Are you designing connections to the roof truss for lighting? Or the truss itself? The loads on the truss should come from a global analysis of the structure, and the type of structure the roof truss is part of will determine what chapter to use.

 

[KootK]

I think it should chapter 13 or 15 because the roof is a thing of its own.

Conceptually, I agree. Your truss will be a rigid thing rigidly attached to a building level, very much like a piece of mechanical equipment might be. That said, I myself would take a different path:

1) For lateral seismic loads on the truss, use the same acceleration applied to the diaphragm at that level.

2) For vertical seismic loads on the truss, use the short period values that apply to the building as a whole.