A.1. Default Load Case and Combination Factors
spColumn allows defining up to 50 load combinations. The user has full control over the combinations. The program contains predefined (built into the program) default primary load combinations for the supported codes. These default combinations are created when starting a new project. The default load combinations of the Dead (D), Live (L), Wind (W), Earthquake (E) and Snow (S) loads considered by the program are shown below.
For the ACI 318-19,14, 11 codes1:
U1 = 1.4D
U2 = 1.2D + 1.6L + 0.5S
U3 = 1.2D + 1L + 1.6S
U4 = 1.2D + 0.5W + 1.6S
U5 = 1.2D - 0.5W + 1.6S
U6 = 1.2D + 1L + 1W + 0.5S
U7 = 1.2D + 1L - 1W + 0.5S
U8 = 1.2D + 1L + 1E + 0.2S
U9 = 1.2D + 1L - 1E + 0.2S
U10 = 0.9D + 1W
U11 = 0.9D - 1W
U12 = 0.9D + 1E
U13 = 0.9D - 1E
For the ACI 318-08, 05 and 02 codes2:
U1 = 1.4D
U2 = 1.2D + 1.6L + 0.5S
U3 = 1.2D + 1L + 1.6S
U4 = 1.2D + 0.8W + 1.6S
U5 = 1.2D - 0.8W + 1.6S
U6 = 1.2D + 1L + 1.6W + 0.5S
U7 = 1.2D + 1L - 1.6W + 0.5S
U8 = 1.2D + 1L + 1E + 0.2S
U9 = 1.2D + 1L - 1E + 0.2S
U10 = 0.9D + 1.6W
U11 = 0.9D - 1.6W
U12 = 0.9D + 1E
U13 = 0.9D - 1E
For CSA A23.3-19 and CSA A23.3-14 codes3:
U1 = 1.4D
U2 = 1.25D + 1.5L + 1S
U3 = 0.9D + 1.5L + 1S
U4 = 1.25D + 1.5L + 0.4W
U5 = 1.25D + 1.5L - 0.4W
U6 = 0.9D + 1.5L + 0.4W
U7 = 0.9D + 1.5L - 0.4W
U8 = 1.25D + 1L + 1.5S
U9 = 0.9D + 1L + 1.5S
U10 = 1.25D + 0.4W + 1.5S
U11 = 1.25D - 0.4W + 1.5S
U12 = 0.9D + 0.4W + 1.5S
U13 = 0.9D - 0.4W + 1.5S
U14 = 1.25D + 0.5L + 1.4W
U15 = 1.25D + 0.5L - 1.4W
U16 = 1.25D + 1.4W + 0.5S
U17 = 1.25D - 1.4W + 0.5S
U18 = 0.9D + 0.5L + 1.4W
U19 = 0.9D + 0.5L - 1.4W
U20 = 0.9D + 1.4W + 0.5S
U21 = 0.9D - 1.4W + 0.5S
U22 = 1D + 0.5L + 1E + 0.25S
U23 = 1D + 0.5L - 1E + 0.25S
For the CSA A23.3-04 code4:
U1 = 1.4D
U2 = 1.25D + 1.5L + 0.5S
U3 = 0.9D + 1.5L + 0.5S
U4 = 1.25D + 1.5L + 0.4W
U5 = 1.25D + 1.5L - 0.4W
U6 = 0.9D + 1.5L + 0.4W
U7 = 0.9D + 1.5L - 0.4W
U8 = 1.25D + 0.5L + 1.5S
U9 = 0.9D + 0.5L + 1.5S
U10 = 1.25D + 0.4W + 1.5S
U11 = 1.25D - 0.4W + 1.5S
U12 = 0.9D + 0.4W + 1.5S
U13 = 0.9D - 0.4W + 1.5S
U14 = 1.25D + 0.5L + 1.4W
U15 = 1.25D + 0.5L - 1.4W
U16 = 1.25D + 1.4W + 0.5S
U17 = 1.25D - 1.4W + 0.5S
U18 = 0.9D + 0.5L + 1.4W
U19 = 0.9D + 0.5L - 1.4W
U20 = 0.9D + 1.4W + 0.5S
U21 = 0.9D - 1.4W + 0.5S
U22 = 1D + 0.5L + 1E + 0.25S
U23 = 1D + 0.5L - 1E + 0.25S
For the CSA A23.3-94 code5:
U1 = 1.25D
U2 = 1.25D + 1.5L + 1.5S
U3 = 0.85D + 1.5L + 1.5S
U4 = 1.25D + 1.05L + 1.05W + 1.05S
U5 = 1.25D + 1.05L – 1.05W + 1.05S
U6 = 0.85D + 1.05L + 1.05W + 1.05S
U7 = 0.85D + 1.05L – 1.05W + 1.05S
U8 = 1.25D + 1.5W
U9 = 1.25D – 1.5W
U10 = 0.85D + 1.5W
U11 = 0.85D – 1.5W
U12 = 1D + 1E
U13 = 1D – 1E
U14 = 1D + 0.5L + 1E + 0.5S
U15 = 1D + 0.5L – 1E + 0.5S
1. ACI 318-19, 5.3; ACI 318-14, 5.3; ACI 318-11, 9.2; ACI 318-08, 9.2; ACI 318-05, 9.2; ACI 318-02, 9.2; (Assuming W based on service-level wind load and E based on ultimate-level forces)
2. ACI 318-19, 5.3; ACI 318-14, 5.3; ACI 318-11, 9.2; ACI 318-08, 9.2; ACI 318-05, 9.2; ACI 318-02, 9.2; (Assuming W based on service-level wind load and E based on ultimate-level forces)
3. CSA A23.3-14/19 Annex C, Table C1; NBCC 2010 [10], Table 4.1.3.2A
4. CSA A23.3-04, 8.3.2; CSA A23.3-04, Annex C, Table C1; NBCC 2005 [10], Table 4.1.3.2
5. CSA A23.3-94, 8.3.2 (conservatively assuming storage and assembly occupancies)