Nominal Load Combinations for Allowable Stress Design in ASCE 7-10

April 13, 2018 Abdul Siraj, P.E.

In this post, I will provide a brief overview of the nominal load combinations for allowable stress design that are specified in ASCE 7-10, Section 2.4. Before identifying the load combinations, it’s a good idea to review the definitions of parameters used in these allowable stress design load combination formulas.

 

Parameter Definitions

D = Dead Load

E = Earthquake Load

L =Live Load

Lr = Roof Live Load

R = Rain Load

S = Snow Load

W = Wind Load

 

Load Combinations for Allowable Stress Design, Formulas

  1. D
  2. D + L
  3. D + (Lr or S or R)
  4. D + 0.75L + 0.75(Lr or S or R)
  5. D + (0.6W or 0.7E)
  6. D + 0.75L + 0.75(0.6W) + 0.75(Lr or S or R)
  7. D + 0.75L + 0.75(0.7E) + 0.75S
  8. 0.6D + 0.6W
  9. 0.6D + 0.7E

 

Load Combinations for Allowable Design, Text

  1. Dead load
  2. Dead load + Live load
  3. Dead load + the maximum of (roof live load or snow load or rain load)
  4. Dead load + 0.75 times live load + 0.75 times the maximum of (roof live load or snow load or rain load) 
  5. Dead load + the maximum of (0.6 times wind load or 0.7 times earthquake load)
  6. Dead load + 0.75 times live load + 0.75 times 0.6 times wind load + 0.75 times the maximum of (roof live load or snow load or rain load)
  7. Dead load + 0.75 times live load + 0.75 times 0.7 times earthquake load + 0.75 times snow load
  8. 0.6 times dead load + 0.6 times wind load
  9. 0.6 times dead load + 0.7 times earthquake load