Live Load Reduction

[MOOK]

I have a question about live load reduction in ROOFS (NOT FLOORS)

I understand from ASCE that if live load is more than 20 lb/ft2 on the ROOF, live load reduction is not applicable. Is that correct?

ASCE is ambiguous in this point.

 

[dastuff]

The IBC (SS 1607.11.2.2) says "Roofs used for promenade purposes, roof gardens, assembly purposes, or other special purposes shall..."

Basically you're allowed to use the minimum allowable design from table 1607.1 and then use a live load reduction factor from SS 1607.9. And IBC will trump ASCE on this issue.

 

[McEngr]

The IBC (SS 1607.11.2.2) says "Roofs used for promenade purposes, roof gardens, assembly purposes, or other special purposes shall..."
Basically you're allowed to use the minimum allowable design from table 1607.1 and then use a live load reduction factor from SS 1607.9. And IBC will trump ASCE on this issue.

+1

 

[MOOK]

The IBC (SS 1607.11.2.2) says "Roofs used for promenade purposes, roof gardens, assembly purposes, or other special purposes shall..."
Basically you're allowed to use the minimum allowable design from table 1607.1 and then use a live load reduction factor from SS 1607.9. And IBC will trump ASCE on this issue.

Thanks dastuff for your answer.

Please correct me if I am worng. If live load on a roof is more than 20psf it will be special roof and shall be treated as FLOOR regarding live load reduction.

 

[dastuff]

Nope that's right... The code only has roof live loads going up to 20 psf.

Anything above that will be considered a special roof, and my previous explanation will fit. Unless of course if you are designing for over 100 psf where no reduction can take place (unless it fits into one of the exceptions).

Isn't code fun!