Load combinations for strength design are applied automatically according to reinforced concrete, stuctural steel and seismic regulations.
Symbols
Em = Combined applied design force on the horizontal and vertical seismic load effects
Emh= The effect of horizontal seismic forces including overstrength
Ev = Vertical seismic load effect
LOAD COMBINATIONS FOR STRENGTH DESIGN (Reinforced Concrete, LRFD)
Basic Combinations
Basic load combinations used for the strength design are given below.
1.4D
1.2D + 1.6L + 0.5(Lr or S)
1.2D + 1.6(Lr or S) + (L or 0.5W)
1.2D + 1.0W + L + 0.5(Lr or S)
0.9D + 1.0W
Basic Combinations with Seismic Load Effects
E = f (Ev; Eh) (defined in Section 12.4.2 or 12.4.3.1) is combined with the effects of other loads, according to ASCE 7-16 Section 2.3.1, basic combinations below is considered.
1.2D + Ev + Eh + L + 0.2S
0.9D - Ev + Eh
Where the seismic load effect with overstrength, Em = f(Ev; Emh), defined in Section 12.4.3, is combined with the effects of other loads, the following seismic load combination for structures is applied:
1.2D + Ev + Emh + L + 0.2S
0.9D - Ev + Emh
The principal loads in the load combinations are identified in Table C2.3-1.
Load combination requirements in Section 2.3 apply only to strength limit states. Serviceability limit states and associated load factors are covered in Appendix C of ASCE 7-16.
1.4D
1.2D + 1.6L + 0.5(Lr or S)
1.2D + 1.6(Lr or S) + (L or 0.5W)
1.2D + 1.0W + L + 0.5(Lr or S)
0.9D + 1.0W
1.2D + Ev + Eh + L + 0.2S
0.9D - Ev + Eh
LOAD COMBINATIONS FOR ALLOWABLE STRESS DESIGN - (ASD)
Basic Combinations
Basic load combinations used for the strength design are given below.
D
D + L
D + (Lr or S)
D + 0.75L + 0.75(Lr or S)
D + 0.6W
D + 0.75L + 0.75(0.6W) + 0.75(Lr or S)
0.6D + 0.6W
Basic Combinations with Seismic Load Effects
When a structure is subject to seismic load effects, the following load combinations is applied in addition to the basic combinations and associated Exceptions in Section 2.4.1. E =f(Ev; Eh) (defined in Section 12.4.2) is combined with the effects of other loads, the following seismic load combinations is applied.
Where the seismic load effect with overstrength, Em = f(Ev; Emh), defined in Section 12.4.3, is combined with the effects of other loads.