live load reduction drawing terminology
 

live load reduction drawing terminology
not being a design engineer, i have a question on standard terminology. i know how to evaluate and use live load reductions; however, we have been asked to interpret drawings that indicate the design live load is "80 psf reduced". how can this be stated for the entire floor when various members typically support small or large areas? i take it to mean that if the member supports the larger area and based on that the larger load can be reduced to 80 psf, then it is ok or for small areas where the load cannot be reduced, the ll max is 80. correct me if i'm wrong.

that note is in error. it should read something like this : "live load 100 psf (reducible for tributary area)".
the 100 psf is the basic, unreduced ll, and you take a percentage reduction based on area to get it less than 100 psf on areas greater than 150 sq. ft.
i agree with sacrebleu on one point, the term i use is reducible. but i wouldn't neccessarily say that note is in error, just unclear. he could have written "80 psf reduced for tributary area" and the note is much clearer.
maybe the note was written after calcs and the person was thinking in past tense, "the load i used was 80 psf reduced ... for tributary area."
rik
if i reduce live load, i state the actual load and follow it with "reducible".
this is what i am used to seeing and i agree with sacrebleu
regards,
lutfi
busman....the actual load is the requirement....the reduction is an engineering judgment applied by the designer and it is optional. i agree with sacrebleu to state the actual design and then state its reducibility for tributary area or other considerations.