Load Combination and Strength Design per ASCE 7-16 §2.3

ASCE 7-16 LRFD and ASD Load Combinations Symbols in ideCAD Structural Software for ASCE 7-16

D = Dead load
E_m = Combined applied design force on the horizontal and vertical seismic load effects
E_mh= The effect of horizontal seismic forces, including overstrength
L = Live load
L_r = roof live load
S = snow load
W = Wind load
E_h = Horizontal seismic load effect
E_v = Vertical seismic load effect

LOAD COMBINATIONS FOR STRENGTH DESIGN (Reinforced Concrete, LRFD) in ideCAD Structural Software for ASCE 7-16

Basic Combinations

Basic load combinations used for the strength design are given below.

• 1.4D

• 1.2D + 1.6L + 0.5(L_r or S)

• 1.2D + 1.6(L_r 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 (E_v; E_h) (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 are considered.

• 1.2D + E_v + E_h + L + 0.2S

• 0.9D - E_v + E_h

Where the seismic load effect with overstrength, E_m = f(E_v; E_mh), 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 + E_v + E_mh + L + 0.2S

• 0.9D - E_v + E_mh

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. Appendix C of ASCE 7-16 covers serviceability limit states and associated load factors.

• 1.4D

• 1.2D + 1.6L + 0.5(L_r or S)

• 1.2D + 1.6(L_r or S) + (L or 0.5W)

• 1.2D + 1.0W + L + 0.5(Lr or S)

• 0.9D + 1.0W

• 1.2D + E_v + E_h + L + 0.2S

• 0.9D - E_v + E_h

LOAD COMBINATIONS FOR ALLOWABLE STRESS DESIGN - (ASD) in ideCAD Structural Software for ASCE 7-16

Basic Combinations

Basic load combinations used for the strength design are given below.

• D

• D + L

• D + (L_r or S)

• D + 0.75L + 0.75(L_r or S)

• D + 0.6W

• D + 0.75L + 0.75(0.6W) + 0.75(L_r 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 are applied in addition to the basic combinations and associated Exceptions in Section 2.4.1. E =f(E_v; E_h) (defined in Section 12.4.2) is combined with the effects of other loads; the following seismic load combinations are applied.

• 1.0D + 0.7E_v + 0.7E_h

• 1.0D + 0.525E_v + 0.525E_h + 0.75L + 0.75S

• 0.6D - 0.7E_v + 0.7E_h

Where the seismic load effect with overstrength, E_m = f(E_v; E_mh), defined in Section 12.4.3, is combined with the impact of other loads.

• 1.0D + 0.7E_v + 0.7E_mh

• 1.0D + 0.525E_v + 0.525E_mh + 0.75L + 0.75S

• 0.6D - 0.7E_v + 0.7E_mh

Next Topic

Application of Combining Earthquake Impact with Other Impacts per ASCE 7-16 with ideCAD

Related Topics

• Analysis Procedure Selection per ASCE 7-16 §12.6

• Modeling Criteria per ASCE 7-16 §12.7

• Modeling of Masses per ASCE 7-16 with ideCAD

• Effective Section Stiffness per ASCE 7-16 §12.7.3

• Equivalent Lateral Force Method (ELF) per ASCE 7-16 §12.8