Analysis of OWSJ truss for HVAC point load

[jt0716]

I'm having issues determining my limiting forces on an existing truss. I've determined that the truss is a 24LH05. I've also figured that under distributed loading of snow and dead loads, i'm within the allowable limits. In addition, if i convert the point load to a distributed load, i'm within allowable limits, however, i know the nature of the truss doesnt necessarily work that way. I'm trying to certify whether a roof-mounted HVAC unit (800#) can span two adjacent trusses (6.5' spacing) without compromising the truss. I can solve for joint forces, but i cant figure out how to determine my limiting factors due to point loads. I appreciate further advice..

 

[JAE]

Take a look at these two previous threads:

thread507-134172

thread507-127992

 

[BAretired]

Don't forget to consider snow drift resulting from the roof projection. That is often the determining factor. It would be a rare case where two joists designed for a uniform snow load are capable of carrying an 800# mechanical unit without modification.

BA