ceiling live load

[Triangled]

I'm checking a bowstring truss with a ceiling framed into the lower chord. What live load at ceiling would you use and would you apply it simultaneously with roof live load? It looks uninhabitable and I see no signs of storage use.

 

[anex20]

If a rectangle 3'-6" X 2'-0" fits between any of the members, a 20 PSF Live Load needs to be applied in that area. Attic live loads are concurrent with roof live load. Use the ASCE 7 load combinations.

 

[oldestguy]

What if the trusses are on 2'-0" centers?

 

[JAE]

According to ASCE 7 attic live loads are not concurrent with roof live loads....see Table 4-1, footnotes l and m


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[jdgengineer]

If it's a bowstring truss I'm assuming it's a non-residential usage and I believe you would fall under "Storage areas above ceilings" 20 psf live load. This section is not clear if it needs to be combined with roof live load, so I would combine it similar to as noted under footnote "m" referenced by JAE. I would probably be tempted to follow the definition of storage per footnote "l" and only use 10 PSF non-concurrent if you didn't meet the size requirements. Given it is likely non-residential I don't think the code is completely clear, as it is for residential usage.

Depending on the usage, you may also need to review "Primary roof members exposed to a work floor". You may need to design for 2,000# panel point load depending on the space below.