Design Coefficients and Factors for Seismic Force-Resisting Systems

Table 12.2-1 Design Coefficients and Factors for Seismic Force-Resisting Systems

Seismic Force-Resisting Systems	ASCE 7 Section Where Detailing Requirements Are Specified	Response Modification Coefficient, $R$ ^a	Overstrength Factor, $Ω_{0}$ ^g	Deflection Amplification Factor, $C_{d}$ ^b	Structural System Limitations Including Structural Height, $h_{n}$ (ft) Limits^c
					Seismic Design Category
					B	C	D^d	E^d	F^e
A. BEARING WALL SYSTEMS
1. Special reinforced concrete shear walls¹^,^m	14.2	5	$2 \frac{1}{2}$	5	NL	NL	160	160	100
2. Ordinary reinforced concrete shear walls^l	14.2	4	$2 \frac{1}{2}$	4	NL	NL	NP	NP	NP
3. Detailed plain concrete shear walls^l	14.2	2	$2 \frac{1}{2}$	2	NL	NP	NP	NP	NP
4. Ordinary plain concrete shear walls^l	14.2	$1 \frac{1}{2}$	$2 \frac{1}{2}$	$1 \frac{1}{2}$	NL	NP	NP	NP	NP
5. Intermediate precast shear walls^l	14.2	4	$2 \frac{1}{2}$	4	NL	NL	40^k	40^k	40^k
6. Ordinary precast shear walls^l	14.2	3	$2 \frac{1}{2}$	3	NL	NP	NP	NP	NP
7. Special reinforced masonry shear walls	14.4	5	$2 \frac{1}{2}$	$3 \frac{1}{2}$	NL	NL	160	160	100
8. Intermediate reinforced masonry shear walls	14.4	$3 \frac{1}{2}$	$2 \frac{1}{2}$	$2 \frac{1}{4}$	NL	NL	NP	NP	NP
9. Ordinary reinforced masonry shear walls	14.4	2	$2 \frac{1}{2}$	$1 \frac{3}{4}$	NL	160	NP	NP	NP
10. Detailed plain masonry shear walls	14.4	2	$2 \frac{1}{2}$	$1 \frac{3}{4}$	NL	NP	NP	NP	NP
11. Ordinary plain masonry shear walls	14.4	$1 \frac{1}{2}$	$2 \frac{1}{2}$	$1 \frac{1}{4}$	NL	NP	NP	NP	NP
12. Prestressed masonry shear walls	14.4	$1 \frac{1}{2}$	$2 \frac{1}{2}$	$1 \frac{3}{4}$	NL	NP	NP	NP	NP
13. Ordinary reinforced AAC masonry shear walls	14.4	2	$2 \frac{1}{2}$	2	NL	35	NP	NP	NP
14. Ordinary plain AAC masonry shear walls	14.4	$1 \frac{1}{2}$	$2 \frac{1}{2}$	$1 \frac{1}{2}$	NL	NP	NP	NP	NP
15. Light-frame (wood) walls sheathed with wood structural panels rated for shear resistance	14.5	$6 \frac{1}{2}$	3	4	NL	NL	65	65	65
16. Light-frame (cold-formed steel) walls sheathed with wood structural panels rated for shear resistance or steel sheets	14.1	$6 \frac{1}{2}$	3	4	NL	NL	65	65	65
17. Light-frame walls with shear panels of all other materials	14.1 and 14.5	2	$2 \frac{1}{2}$	2	NL	NL	35	NP	NP
18. Light-frame (cold-formed steel) wall systems using flat strap bracing	14.1	4	2	$3 \frac{1}{2}$	NL	NL	65	65	65
B. BUILDING FRAME SYSTEMS
1. Steel eccentrically braced frames	14.1	8	2	4	NL	NL	160	160	100
2. Steel special concentrically braced frames	14.1	6	2	5	NL	NL	160	160	100
3. Steel ordinary concentrically braced frames	14.1	$3 \frac{1}{4}$	2	$3 \frac{1}{4}$	NL	NL	35^j	35^j	NP^j
4. Special reinforced concrete shear walls^l^,^m	14.2	6	$2 \frac{1}{2}$	5	NL	NL	160	160	100
5. Ordinary reinforced concrete shear walls^l	14.2	5	$2 \frac{1}{2}$	$4 \frac{1}{2}$	NL	NL	NP	NP	NP
6. Detailed plain concrete shear walls^l	14.2 and 14.2.2.7	2	$2 \frac{1}{2}$	2	NL	NP	NP	NP	NP
7. Ordinary plain concrete shear walls^l	14.2	$1 \frac{1}{2}$	$2 \frac{1}{2}$	$1 \frac{1}{2}$	NL	NP	NP	NP	NP
8. Intermediate precast shear walls^l	14.2	5	$2 \frac{1}{2}$	$4 \frac{1}{2}$	NL	NL	40^k	40^k	40^k
9. Ordinary precast shear walls^l	14.2	4	$2 \frac{1}{2}$	4	NL	NP	NP	NP	NP
10. Steel and concrete composite eccentrically braced frames	14.3	8	$2 \frac{1}{2}$	4	NL	NL	160	160	100
11. Steel and concrete composite special concentrically braced frames	14.3	5	2	$4 \frac{1}{2}$	NL	NL	160	160	100
12. Steel and concrete composite ordinary braced frames	14.3	3	2	3	NL	NL	NP	NP	NP
13. Steel and concrete composite plate shear walls	14.3	$6 \frac{1}{2}$	$2 \frac{1}{2}$	$5 \frac{1}{2}$	NL	NL	160	160	100
14. Steel and concrete composite special shear walls	14.3	6	$2 \frac{1}{2}$	5	NL	NL	160	160	100
15. Steel and concrete composite ordinary shear walls	14.3	5	$2 \frac{1}{2}$	$4 \frac{1}{2}$	NL	NL	NP	NP	NP
16. Special reinforced masonry shear walls	14.4	$5 \frac{1}{2}$	$2 \frac{1}{2}$	4	NL	NL	160	160	100
17. Intermediate reinforced masonry shear walls	14.4	4	$2 \frac{1}{2}$	4	NL	NL	NP	NP	NP
18. Ordinary reinforced masonry shear walls	14.4	2	$2 \frac{1}{2}$	2	NL	160	NP	NP	NP
19. Detailed plain masonry shear walls	14.4	2	$2 \frac{1}{2}$	2	NL	NP	NP	NP	NP
20. Ordinary plain masonry shear walls	14.4	$1 \frac{1}{2}$	$2 \frac{1}{2}$	$1 \frac{1}{4}$	NL	NP	NP	NP	NP
21. Prestressed masonry shear walls	14.4	$1 \frac{1}{2}$	$2 \frac{1}{2}$	$1 \frac{3}{4}$	NL	NP	NP	NP	NP
22. Light-frame (wood) walls sheathed with wood structural panels rated for shear resistance	14.5	7	$2 \frac{1}{2}$	$4 \frac{1}{2}$	NL	NL	65	65	65
23. Light-frame (cold-formed steel) walls sheathed with wood structural panels rated for shear resistance or steel sheets	14.1	7	$2 \frac{1}{2}$	$4 \frac{1}{2}$	NL	NL	65	65	65
24. Light-frame walls with shear panels of all other materials	14.1 and 14.5	$2 \frac{1}{2}$	$2 \frac{1}{2}$	$2 \frac{1}{2}$	NL	NL	35	NP	NP
25. Steel buckling-restrained braced frames	14.1	8	$2 \frac{1}{2}$	5	NL	NL	160	160	100
26. Steel special plate shear walls	14.1	7	2	6	NL	NL	160	160	100
C. MOMENT-RESISTING FRAME SYSTEMS
1. Steel special moment frames	14.1 and 12.2.5.5	8	3	$5 \frac{1}{2}$	NL	NL	NL	NL	NL
2. Steel special truss moment frames	14.1	7	3	$5 \frac{1}{2}$	NL	NL	160	100	NP
3. Steel intermediate moment frames	12.2.5.7 and 14.1	$4 \frac{1}{2}$	3	4	NL	NL	35^h	NP^h	NP^h
4. Steel ordinary moment frames	12.2.5.6 and 14.1	$3 \frac{1}{2}$	3	3	NL	NL	NPⁱ	NPⁱ	NPⁱ
5. Special reinforced concrete moment framesⁿ	12.2.5.5 and 14.2	8	3	$5 \frac{1}{2}$	NL	NL	NL	NL	NL
6. Intermediate reinforced concrete moment frames	14.2	5	3	$4 \frac{1}{2}$	NL	NL	NP	NP	NP
7. Ordinary reinforced concrete moment frames	14.2	3	3	$2 \frac{1}{2}$	NL	NP	NP	NP	NP
8. Steel and concrete composite special moment frames	12.2.5.5 and 14.3	8	3	$5 \frac{1}{2}$	NL	NL	NL	NL	NL
9. Steel and concrete composite intermediate moment frames	14.3	5	3	$4 \frac{1}{2}$	NL	NL	NP	NP	NP
10. Steel and concrete composite partially restrained moment frames	14.3	6	3	$5 \frac{1}{2}$	160	160	100	NP	NP
11. Steel and concrete composite ordinary moment frames	14.3	3	3	$2 \frac{1}{2}$	NL	NP	NP	NP	NP
12. Cold-formed steel—special bolted moment frame^p	14.1	$3 \frac{1}{2}$	3^o	$3 \frac{1}{2}$	35	35	35	35	35
D. DUAL SYSTEMS WITH SPECIAL MOMENT FRAMES CAPABLE OF RESISTING AT LEAST 25% OF PRESCRIBED SEISMIC FORCES	12.2.5.1
1. Steel eccentrically braced frames	14.1	8	$2 \frac{1}{2}$	4	NL	NL	NL	NL	NL
2. Steel special concentrically braced frames	14.1	7	$2 \frac{1}{2}$	$5 \frac{1}{2}$	NL	NL	NL	NL	NL
3. Special reinforced concrete shear walls^l^,^m	14.2	7	$2 \frac{1}{2}$	$5 \frac{1}{2}$	NL	NL	NL	NL	NL
4. Ordinary reinforced concrete shear walls^l	14.2	6	$2 \frac{1}{2}$	5	NL	NL	NP	NP	NP
5. Steel and concrete composite eccentrically braced frames	14.3	8	$2 \frac{1}{2}$	4	NL	NL	NL	NL	NL
6. Steel and concrete composite special concentrically braced frames	14.3	6	$2 \frac{1}{2}$	5	NL	NL	NL	NL	NL
7. Steel and concrete composite plate shear walls	14.3	$7 \frac{1}{2}$	$2 \frac{1}{2}$	6	NL	NL	NL	NL	NL
8. Steel and concrete composite special shear walls	14.3	7	$2 \frac{1}{2}$	6	NL	NL	NL	NL	NL
9. Steel and concrete composite ordinary shear walls	14.3	6	$2 \frac{1}{2}$	5	NL	NL	NP	NP	NP
10. Special reinforced masonry shear walls	14.4	$5 \frac{1}{2}$	3	5	NL	NL	NL	NL	NL
11. Intermediate reinforced masonry shear walls	14.4	4	3	$3 \frac{1}{2}$	NL	NL	NP	NP	NP
12. Steel buckling-restrained braced frames	14.1	8	$2 \frac{1}{2}$	5	NL	NL	NL	NL	NL
13. Steel special plate shear walls	14.1	8	$2 \frac{1}{2}$	$6 \frac{1}{2}$	NL	NL	NL	NL	NL
E. DUAL SYSTEMS WITH INTERMEDIATE MOMENT FRAMES CAPABLE OF RESISTING AT LEAST 25% OF PRESCRIBED SEISMIC FORCES	12.2.5.1
1. Steel special concentrically braced frames^f	14.1	6	$2 \frac{1}{2}$	5	NL	NL	35	NP	NP
2. Special reinforced concrete shear walls^l^,^m	14.2	$6 \frac{1}{2}$	$2 \frac{1}{2}$	5	NL	NL	160	100	100
3. Ordinary reinforced masonry shear walls	14.4	3	3	$2 \frac{1}{2}$	NL	160	NP	NP	NP
4. Intermediate reinforced masonry shear walls	14.4	$3 \frac{1}{2}$	3	3	NL	NL	NP	NP	NP
5. Steel and concrete composite special concentrically braced frames	14.3	$5 \frac{1}{2}$	$2 \frac{1}{2}$	$4 \frac{1}{2}$	NL	NL	160	100	NP
6. Steel and concrete composite ordinary braced frames	14.3	$3 \frac{1}{2}$	$2 \frac{1}{2}$	3	NL	NL	NP	NP	NP
7. Steel and concrete composite ordinary shear walls	14.3	5	3	$4 \frac{1}{2}$	NL	NL	NP	NP	NP
8. Ordinary reinforced concrete shear walls^l	14.2	$5 \frac{1}{2}$	$2 \frac{1}{2}$	$4 \frac{1}{2}$	NL	NL	NP	NP	NP
F. SHEAR WALL-FRAME INTERACTIVE SYSTEM WITH ORDINARY REINFORCED CONCRETE MOMENT FRAMES AND ORDINARY REINFORCED CONCRETE SHEAR WALLS ^l	12.2.5.8 and 14.2	$4 \frac{1}{2}$	$2 \frac{1}{2}$	4	NL	NP	NP	NP	NP
G. CANTILEVERED COLUMN SYSTEMS DETAILED TO CONFORM TO THE REQUIREMENTS FOR:	12.2.5.2
1. Steel special cantilever column systems	14.1	$2 \frac{1}{2}$	$1 \frac{1}{4}$	$2 \frac{1}{2}$	35	35	35	35	35
2. Steel ordinary cantilever column systems	14.1	$1 \frac{1}{4}$	$1 \frac{1}{4}$	$1 \frac{1}{4}$	35	35	NPⁱ	NPⁱ	NPⁱ
3. Special reinforced concrete moment framesⁿ	12.2.5.5 and 14.2	$2 \frac{1}{2}$	$1 \frac{1}{4}$	$2 \frac{1}{2}$	35	35	35	35	35
4. Intermediate reinforced concrete moment frames	14.2	$1 \frac{1}{2}$	$1 \frac{1}{4}$	$1 \frac{1}{2}$	35	35	NP	NP	NP
5. Ordinary reinforced concrete moment frames	14.2	1	$1 \frac{1}{4}$	1	35	NP	NP	NP	NP
6. Timber frames	14.5	$1 \frac{1}{2}$	$1 \frac{1}{2}$	$1 \frac{1}{2}$	35	35	35	NP	NP
H. STEEL SYSTEMS NOT SPECIFICALLY DETAILED FOR SEISMIC RESISTANCE, EXCLUDING CANTILEVER COLUMN SYSTEMS	14.1	3	3	3	NL	NL	NP	NP	NP

a Response modification coefficient, $R$ , for use throughout the standard. Note $R$ reduces forces to a strength level, not an allowable stress level.

b Deflection amplification factor, $C_{d}$ , for use in Sections 12.8.6, 12.8.7, and 12.9.2.

c NL = Not Limited and NP = Not Permitted. For metric units use 30.5 m for 100 ft and use 48.8 m for 160 ft.

d See Section 12.2.5.4 for a description of seismic force-resisting systems limited to buildings with a structural height, $h_{n}$ , of 240 ft (73.2 m) or less.

e See Section 12.2.5.4 for seismic force-resisting systems limited to buildings with a structural height, $h_{n}$ , of 160 ft (48.8 m) or less.

f Ordinary moment frame is permitted to be used in lieu of intermediate moment frame for Seismic Design Categories B or C.

g Where the tabulated value of the overstrength factor, $Ω_{0}$ , is greater than or equal to $2 \frac{1}{2}$ , $Ω_{o}$ is permitted to be reduced by subtracting the value of $1 / 2$ for structures with flexible diaphragms.

h See Section 12.2.5.7 for limitations in structures assigned to Seismic Design Categories D, E, or F.

i See Section 12.2.5.6 for limitations in structures assigned to Seismic Design Categories D, E, or F.

j Steel ordinary concentrically braced frames are permitted in single-story buildings up to a structural height, $h_{n}$ , of 60 ft (18.3 m) where the dead load of the roof does not exceed 20 psf ( $0.96 kN / m^{2}$ ) and in penthouse structures.

k An increase in structural height, $h_{n}$ , to 45 ft (13.7 m) is permitted for single-story storage warehouse facilities.

l In Section 2.2 of ACI 318. A shear wall is defined as a structural wall.

m In Section 2.2 of ACI 318. The definition of “special structural wall” includes precast and cast-in-place construction.

n In Section 2.2 of ACI 318. The definition of “special moment frame” includes precast and cast-in-place construction.

o Alternately, the seismic load effect with overstrength, $E_{mh}$ , is permitted to be based on the expected strength determined in accordance with AISI S110.

p Cold-formed steel – special bolted moment frames shall be limited to one story in height in accordance with AISI S110.