Floor Live Load Reduction

[haynewp]

According to UBC 97', floor live loads may be reduced by R=0.08(A-150)for members supporting 150ft^2 or more in area and meeting other general criteria. However, I interpret SBC 97' as floor live loads may be reduced by R=0.08*A for area> 150ft^2 with most all other general stipulations being the same as stated by UBC but without subtracting the 150 from the total area supported. Is this the way others are applying the reduction when using SBC or do you think they mean R=0.08(A-150) as in UBC?

 

[JAE]

In the 1999 SBC, I read it as R = .08 x (A)

It does say "per sq ft of the area supported" and there is no reference to A-150.

The IBC 2000 maintains the UBC method (A-150).

 

[haynewp]

thanks

 

[JAE]

haynewp:
I forgot to mention that the SBC 91 through 94 codes have the same language. This creates a less conservative live load which you MAY use, but if you desire, use the more conservative approach (A-150) and you'll still meet the SBC min. requirements.

 

Hi,

I live in San Francisco and I am buildinga rectangular deck (one story up) of approx. 77.40 s.ft.

I have run across a problem?

What is live load? deck____ stairs____
What is static load? deck____ stairs____

How do I calculate this?

 

[dik]

It should be prescribed in the building code. Depending on the code, I've encountered values from 40 psf to 100 psf for the deck and 60 psf to 100 psf for the stairs. The building code in effect for the area likely has a part that describes the live loads to be used for various building components. You can likely check with your local buiding inspector/plan examiner to find out what the value is.