Uniform Live Load Reduction Using ASCE 7-10, Section 4.7

April 16, 2018 Abdul Siraj, P.E.

In this post, I will provide a brief overview of how to reduce uniform live loads using ASCE 7-10, Section 4.7. This post does not cover the reduction of roof uniform live loads. .

 

Uniform Live Load Reduction Formula, ASCE Equation 4.7-1

 

 

Parameter Definitions

 

L = Reduced design live load per ft2 (m2) of area supported by the member

Lo = Unreduced design live load per ft2 (m2) of area supported by the member (ASCE 7-10, Table 4-1)

AT = Tributary area in ft2 (m2)

KLL = Live Load Element Factor (Table 4-2)

 

Limitations / Conditions for Reducing Live Loads

 

  1. Uniform live loads may only be reduced if the limitations listed in Sections 4.7.3 – 4.7.6 are satisfied
  2. Uniform load loads may only be reduced for members for which the product of the live load element factor and tributary area is at least 400 ft(KLL*AT ≥ 400)
  3. L  ≥ 0.5L for members supporting one floor
  4. L  ≥ 0.4L for members supporting two or more floors