Chapter 2 Appendix: Jonathan Ochshorn's Structural Elements text, Third Edition

Table A-2.1: Dead loads

A. Basic volumetric weights in pounds per cubic foot (pcf)
Stone: Sandstone Granite Marble	144 165 173
Brick/CMU/concrete Normal-weight reinforced concrete	100 – 145 150
Metals: Aluminum Steel Lead	165 492 710
Glass	160
Wood	25 – 50
Water	64
Earth: Dry clay Silt, moist and packed Wet sand and gravel	63 96 120
Insulation: Glass fiber batts Expanded polystyrene boards Extruded polystyrene boaards Polyisocyanurate boards Fiberboard	0.8 0.9 – 1.8 2.2 2.0 1.5

B. Distributed loads in pounds per square feet (psf)
Wood floor system: 2 × 10 joists at 16 in. on center, wood finish floor and subfloor, gypsum board ceiling	10.5
Steel floor system: 4-1/2 in. corrugated steel deck with concrete slab, tile floor, mechanical ducts, suspended tile ceiling	47
Concrete floor system: 6 in. reinforced concrete slab, tile floor, mechanical ducts, suspended tile ceiling	80
Floor-ceiling components: Harwood finish floor, 7/8 in. Wood subfloor, 3/4 in. Acoustical tile with suspended steel channels Mechanical duct allowance Steel stud partition allowance	4.0 2.5 3.0 4.0 8.0
Sheathing: Plywood, per 1/8 in. thickness Gypsum board, per 1/8 in. thickness	0.40 0.55

Table A-2.2: Live loads

A. Typical live loads based on occupancy (psf)
Assembly areas with fixed seats	60
Assembly areas with movable seats	100
Lobbies, corridors (first floor)	100
Dining rooms and restaurants	100
Garages for passenger cars	40
Libraries, reading rooms	60
Libraries, stack areas (not less than)	150
Manufacturing, light	125
Manufacturing, heavy	250
Office buildings	50
Dwellings and hotels (except as noted below)	40
Note: Residential sleeping areas	30
Schools (classrooms)	40
Schools (corridors above first floor)	80
Stadium and arena bleachers	100
Stairs and exitways	100
Stores, retail (first floor)	100
Stores, retail (upper floors)	75
Stores, wholesale (all floors)	125

B.Live load reduction coefficient^{^1,2,3,4}

Notes for Part B:

1. K_LL is the live load element factor and is defined as follows for selected common beam and column configurations:

K_LL = 4 for columns without cantilever slabs

K_LL = 3 for edge columns with cantilever slabs

K_LL = 2 for corner columns with cantilever slabs

K_LL = 2 for beams (except as noted below)

K_LL = 1 for one-way and two-way slabs, edge beams with cantilever slabs, and anything else not previously mentioned — and note that A_T for one-way slabs cannot be taken as more than 1.5 × (slab span)²

2. A_T is the tributary area of the element being considered (ft²)

3. No live load reduction applies when K_LLA_T ≤ 400 ft² or when the element supports a single floor with live load > 100 psf (for an element supporting more than one floor with live loads > 100 psf, a reduction no greater than 20% is permitted)

4. Reduction coefficient cannot be taken greater than 1.0; nor can it be smaller than 0.5 for elements supporting a single floor level; or smaller than 0.4 for all other conditions.

Table A-2.3: Environmental loads¹

City, State	Ground Snow Load (psf)	Basic (Ultimate) Wind Speed, V (mph)				Seismic Ground Motion²
City, State	Ground Snow Load (psf)	Risk Category I	Risk Category II	Risk Category III	Risk Category IV	S_s	S₁	T_L
Boston, MA	40	110	120	128	133	0.270	0.065	6
Chicago, IL	25	100	107	114	119	0.116	0.063	12
Little Rock, AR	10	98	105	111	115	0.387	0.150	12
Houston, TX	0	128	136	145	150	0.068	0.039	12
Ithaca, NY	40	100	110	116	122	0.119	0.045	6
Miami, FL	0	157	169	182	189	0.040	0.020	8
New York, NY	20	106	115	125	129	0.288	0.060	6
Philadelphia, PA	25	105	112	123	125	0.180	0.047	6
Phoenix, AZ	0	95	101	108	112	0.179	0.065	6
Portland, ME	50	103	112	119	125	0.281	0.072	6
San Francisco, CA	0	86	91	98	102	1.500	0.600	12

Notes:

1. Approximate values taken from snow, wind, and seismic maps. Various web-based applications are available to find environmental loads at specific locations in the U.S. See, for example:

SNOW, WIND, and SEISMIC: https://hazards.atcouncil.org/ [Applied Technology Council (ATC)]

SEISMIC (disaggregated): https://seismicmaps.org/ [California's Office of Statewide Health Planning and Development (OSHPD)]

2. S_s and S₁ are, respectively, the maximum considered earthquake ground motions of 0.2s (short) and 1s (long) spectral response acceleration (5% of critical damping) for site class B, measured as a fraction of the acceleration due to gravity. TL is the so-called "long-period transition period" (seconds).

Table A-2.4: Snow load Importance factor, I_s

Category	Description	Factor
I	Low hazard (minor storage, etc.)	0.8
II	Regular (ordinary buildings)	1.0
III	Substantial hazard (schools, jails, places of assembly with no fewer than 300 occupants)	1.1
IV	Essential facilities (hospitals, fire stations, etc.)	1.2

Table A-2.5: Wind coefficients

A. Velocity pressure coefficient, K_z¹
Height above grade², z (ft)	Exposure B³	Exposure C⁴	Exposure D⁵
500	1.57	1.78	1.90
400	1.47	1.69	1.82
300	1.35	1.59	1.73
200	1.20	1.46	1.62
100	0.99	1.27	1.43
90	0.96	1.24	1.41
80	0.93	1.21	1.38
70	0.89	1.17	1.35
60	0.85	1.14	1.31
50	0.81	1.09	1.27
45	0.79	1.07	1.25
40	0.76	1.04	1.22
35	0.73	1.01	1.19
30	0.70	0.98	1.16
25	0.67	0.95	1.13
20	0.62	0.90	1.08
0 – 15	0.57	0.85	1.03

Notes for Part A:

1. Values of K_z are based on the following equation, where z is the height above grade (ft); α = 7.0 for Exposure B; 9.5 for Exposure C, and 11.5 for Exposure D; and z_g = 1200 for Exposure B; 900 for Exposure C; and 700 for Exposure D:

When using tabular values for K, linear interpolation between values is permitted.

2. When computing pressures on windward surfaces, use height z corresponding to height for which pressure is being computed; for all other surfaces, use z = h (mean roof height: i.e., use this single value of z for the entire surface). See Table A-2.5 Part H for graphic explanation of building geometry parameters.

3. Exposure B refers to urban or suburban areas, wooded areas, etc.

4. Exposure C refers to open terrain with scattered obstructions, excluding water surfaces in hurricane regions.

5. Exposure D refers to flat, unobstructed areas like mud flats, salt flats, or water, both inside or outside of hurricane regions.

B. External pressure coefficient for walls, C_p¹
Orientation	0 ≤ L/B ≤ 1	L/B = 2	L/B ≥ 4
Windward	0.8	0.8	0.8
Leeward	–0.5	–0.3	–0.2
Side	–0.7	–0.7	–0.7

Note for Part B:

1. L and B are the plan dimensions of the rectangular building, with B being the dimension of the windward and leeward walls, and L the dimension of the side walls. See Table A-2.5 Part H for graphic explanation of building geometry parameters.

C. External pressure coefficient on windward slope of roof, C_p, for wind direction normal to ridge^{^1,2,7}
Roof angle, θ (deg)	h/ L ≤ 0.25	h/ L = 0.50	h/ L ≥ 1.0
⁶θ < 10 0 < D ≤ h/2 h/ 2 < D ≤ h h < D ≤ 2h 2h < D	–0.9, -0.18 –0.9, -0.18 –0.5, -0.18 –0.3, -0.18	–0.9, -0.18 –0.9, -0.18 –0.5, -0.18 –0.3, -0.18	³–1.3, -0.18 –0.7, -0.18 –0.7, -0.18 –0.7, -0.18
⁶θ = 10	–0.7, –0.18	–0.9, –0.18	³–1.3, –0.18
θ = 15	–0.5, 40.0	–0.7, –0.18	–1.0, –0.18
θ = 20	–0.3, 0.2	–0.4, ⁴0.0	–0.7, –0.18
θ = 25	–0.2, 0.3	–0.3, 0.2	–0.5, ⁴0.0
θ = 30	–0.2, 0.3	–0.2, 0.2	–0.3, 0.2
θ = 35	⁴0.0, 0.4	–0.2, 0.3	–0.2, 0.2
θ = 45	0.4	⁴0.0, 0.4	⁴0.0, 0.3
⁵θ ≥ 60	0.01θ	0.01θ	0.01θ

Notes for Part C:

1. Where two values are given, either may apply, and both must be considered. Interpolation between adjacent values is permitted, but must be between numbers of the same sign; where no number of the same sign exists, use 0.0.

2. Values are used with Kz taken at mean roof height. Units of length for D, h, and L must be consistent with each other. For roof angles less than 10°, D refers to the range of horizontal distances from the windward eave (edge) for which the value of C_p applies; h is the height of the eave above grade for roof angles no greater than 10°, otherwise, h is the mean roof height above grade; L is the horizontal length of the building parallel to the wind direction. See Table A-2.5 Part H for graphic explanation of building geometry parameters.

3. Value of –1.3 may be reduced depending on the area it is acting on: for areas no greater than 100 ft², no reduction; for areas of 200 ft², multiply by 0.9; for areas no smaller than 1000 ft², multiply by 0.8; interpolate between given values.

4. Values of 0.0 are used only to interpolate between adjacent fields.

5. Roof angles over 80° are treated as windward walls, with C_p = 0.8.

6. See Note 2 for roof height, h, where roof angle is no greater than 10°.

7. Negative numbers indicate "suction," i.e., forces acting away from the building surface; positive numbers indicate forces "pushing" against the building surface.

Table A-2.5: Wind coefficients (continued)

D. External pressure coefficient on leeward slope of roof, C_p, for wind direction normal to ridge^{^1,2,3}
Roof angle, θ (deg)	h/L ≤ 0.25	h/L = 0.50	h/L ≥ 1.0
θ = 10	–0.3	–0.5	–0.7
θ = 15	–0.5	–0.5	–0.6
θ ≥ 20	–0.6	–0.6	–0.6

Notes for Part D:

1. The height h is measured to the eave for roof angles equal to 10°, otherwise, h is the mean roof height above grade; L is the horizontal length of the building parallel to the wind direction. See Table A-2.5 Part H for graphic explanation of building geometry parameters.

2. For roof angles less than 10°, the roof is considered to be flat, and no leeward pressures are computed. Instead, use the values in Table A.2.4 Part C for the entire roof.

3. Interpolation is permitted between values.

4. Negative numbers indicate "suction," i.e., forces acting away from the building surface; positive numbers indicate forces "pushing" against the building surface.

E. External pressure coefficient roof, C_p, for wind direction parallel to ridge, for all roof angles^{^1,2,4,5}
Applicable Roof Area	h/L ≤ 0.25	h/L = 0.50	h/L ≥ 1.0
0 < D ≤ h/2	–0.9, –0.18	-0.9, –0.18	³–1.3, –0.18
h/ 2 < D ≤ h	–0.9, –0.18	-0.9, –0.18	–0.7, –0.18
h < D ≤ 2h	–0.5, –0.18	–0.5, –0.18	–0.7, –0.18
2h < D	–0.3, –0.18	–0.3, –0.18	–0.7, –0.18

Notes for Part E:

1. Where two values are given, either may apply, and both must be considered. Interpolation between adjacent values is permitted, but must be between numbers of the same sign.

2. Values are used with K taken at mean roof height. Units of length for D, h, and L must be consistent with each other. For all roof angles, D refers to the range of horizontal distances from the windward eave (edge) for which the value of C_p applies; h is the height of the eave above grade for roof angles no greater than 10°, otherwise, h is the mean roof height above grade; L is the horizontal length of the building parallel to the wind direction. See Table A-2.5 Part H for graphic explanation of building geometry parameters.

4. Roof angles over 80° are treated as windward walls, with C_p = 0.8.

5. Negative numbers indicate "suction," i.e., forces acting away from the building surface; positive numbers indicate forces "pushing" against the building surface.

F. Gust effect factor, G
In lieu of more complex calculations, use G = 0.85 for so-called "rigid" buildings: such buildings are in most cases no more than 4 times taller than their minimum width, and have a fundamental frequency of at least 1 Hz (1 cycle per second).

G. Importance factor, I_w
Category	Description	Factor¹
I	Low hazard (minor storage, etc.)	—
II	Regular (ordinary buildings)	—
III	Substantial risk to human life or major economic impact, with or without significant disruption of daily life	—
IV	Essential facilities (hospitals, fire stations, etc.)	—

Note for Part G:

1. Importance factors for wind are no longer used directly in calculations; instead, consideration of importance (risk) has been incorporated within basic wind speed maps and wind speed values.

H. Graphic definition of building parameters¹

Note for Part H:

1. When using Table A-2.5 Parts C, D, and E, the roof height, h, is measured to the mean roof elevation, except for roof angles less than or equal to 10°, in which case h is measured to the eave, as indicated by the dotted line.

Table A-2.5: Wind coefficients (continued)

I. Ground elevation factor

Notes for Part I:

1. The ground elevation factor is permitted to be taken, conservatively, as 1.0 for all buildings at or above sea level; or, nonconservatively, as 1.0 for buildings below sea level.

2. Alternatively, values for buildings at ground level elevations between 0 and 6,000 feet can be interpolated from the values shown in the graph above.

3. The values in the graph are based on the equation, K_e = e^{–0.0000362K_g}; this equation — with K_g being the ground elevation above sea level in feet — can be used in lieu of the values shown above and, in fact, for any elevation, whether below sea level or greater than 6,000 feet above sea level. In this equation, e is the base of the natural logarithms ("Euler's number") and is approximately equal to 2.718. In many common spreadsheet programs — with the elevation above sea level (feet) in cell A1 — the equation for K_e would be written as: =EXP(-0.0000362 * A1).

Table A-2.6: Seismic coefficients

A. Site coefficient, F_a
	S_s ≤ 0.25	S_s = 0.5	S_s = 0.75	S_s = 1.0	S_s = 1.25	S_s ≥ 1.5
A = hard rock	0.8	0.8	0.8	0.8	0.8	0.8
B = rock	0.9	0.9	0.9	0.9	0.9	0.9
C = dense soil or soft rock	1.3	1.3	1.2	1.2	1.2	1.2
D = stiff soil	1.6	1.4	1.2	1.1	1.0	1.0
E = soft soil	2.4	1.7	1.3	Need site-specific investigation
F = liquifiable soils, etc.	Need site-specific investigation

B. Site coefficient, F_v
	S₁ ≤ 0.1	S₁ = 0.2	S₁ = 0.3	S₁ = 0.4	S₁ = 0.5	S₁ ≥ 0.6
A = hard rock	0.8	0.8	0.8	0.8	0.8	0.8
B = rock	0.8	0.8	0.8	0.8	0.8	0.8
C = dense soil or soft rock	1.5	1.5	1.5	1.5	1.5	1.4
D = stiff soil	2.4	¹2.2	¹2.0	¹1.9	¹1.8	¹1.7
E = soft soil	4.2	Need site-specific investigation
F = liquifiable soils, etc.	Need site-specific investigation

Note for Part B:

1. Site-specific investigation may be required in certain cases where S₁ ≥ 0.2 in Site Class D.

C. Design elastic response acceleration, S_DS and S_D₁
^{^1,2}S_DS = (2/3)(F_a)(S_s)	¹S_D₁ = (2/3)(F_a)(S₁)

Note for Part C:

1. See Table A-2.3 for selected values of S_s and S₁. See Table A-2.5, Parts A and B for F_a and F_v respectively.

2. In certain circumstances, the value of S_DS used in the calculation of C_s and E_v can be taken as the larger of 1.0 and 0.7S_DS. In particular, the structure must be no higher than five stories, must have no irregularities, must be Risk Category I or II and Site Class A through D. There are additional requirements involving a so-called redundancy factor, ρ, that would need to be checked for Site Class D; this examination is beyond the scope of this book.

Table A-2.6: Seismic coefficients (continued)

D. Response modification coefficient, R (including height and other limitations based on seismic design category¹)
Bearing wall systems
01. Special reinforced concrete shear walls (^{^1,2}categories D, E limited to 160 ft; F limited to 100 ft)	5
02. Ordinary reinforced concrete shear walls (¹not permitted in categories D – F)	4
03. Detailed plain concrete shear walls (¹not permitted in categories C – F)	2
04. Ordinary plain concrete shear walls (¹not permitted in categories C – F)	1.5
05. Intermediate precast shear walls (^{^1,2}categories D – F limited to 40 ft)	4
06. Ordinary precast shear walls (¹not permitted in categories C – F)	3
07. Special reinforced masonry shear walls (¹categories D, E limited to 160 ft; F limited to 100 ft)	5
08. Intermediate reinforced masonry shear walls (¹not permitted in categories D – F)	3.5
09. Ordinary reinforced masonry shear walls (¹not permitted in categories D – F; C limited to 160 ft)	2
10. Detailed plain masonry shear walls (¹not permitted in categories C – F)	2
11. Ordinary plain masonry shear walls (¹not permitted in categories C – F)	1.5
12. Prestressed masonry shear walls (¹not permitted in categories C – F)	1.5
13. Ordinary reinforced AAC [Autoclaved Aerated Concrete] masonry shear walls (¹category C limited to 35 ft; not permitted in categories D – F)	2
14. Ordinary plain AAC [Autoclaved Aerated Concrete] masonry shear walls (¹not permitted in categories C – F)	1.5
15. Light-frame (wood) walls sheathed with wood structural panels rated for shear resistance, or steel sheets (¹categories D – F limited to 65 ft)	6.5
16. Light-frame (cold-formed steel) walls sheathed with wood structural panels rated for shear resistance, or steel sheets (¹categories D – F limited to 65 ft)	6.5
17. Light-frame walls with shear panels of all other materials (¹category D limited to 35 ft; not permitted in categories E, F)	2
18. Light-frame (cold-formed steel) wall systems using flat strap bracing (¹categories D – F limited to 65 ft)	4
Building frame systems
01. Steel eccentrically braced frames (^{^1,2}categories D, E limited to 160 ft; F limited to 100 ft)	8
02. Steel special concentrically braced frames (^{^1,2}categories D, E limited to 160 ft; F limited to 100 ft)	6
03. Steel ordinary concentrically braced frames (¹categories D, E limited to 35 ft; category F not permitted)	3.25
04. Special reinforced concrete shear walls (^{^1,2}categories D, EE limited to 160 ft; F limited to 100 ft)	6

D. Response modification coefficient, R (including height and other limitations based on seismic design category¹)
05. Ordinary reinforced concrete shear walls (¹not permitted in categories D – F)	5
06. Detailed plain concrete shear walls (¹not permitted in categories C – F)	2
07. Ordinary plain concrete shear walls (¹not permitted in categories C – F)	1.5
08. Intermediate precast shear walls (^1,2categories D – F limited to 40 ft)	5
09. Ordinary precast shear walls (¹not permitted in categories C – F)	4
10. Composite steel and concrete eccentrically braced frames (¹categories D, E limited to 160 ft; F limited to 100 ft)	8
11. Steel and concrete composite special concentrically braced frames (¹categories D, E limited to 160 ft; F limited to 100 ft)	5
12. Ordinary composite steel and concrete braced frames (¹not permitted in categories D – F)	3
13. Steel and concrete composite plate shear walls (¹categories D, E limited to 160 ft; F limited to 100 ft)	6.5
14. Steel and concrete composite special shear walls (¹categories D, E limited to 160 ft; F limited to 100 ft)	6
15. Steel and concrete composite ordinary shear walls (¹not permitted in categories D – F)	5
16. Special reinforced masonry shear walls (¹categories D, E limited to 160 ft; F limited to 100 ft)	5.5
17. Intermediate reinforced masonry shear walls (¹not permitted in categories D – F)	4
18. Ordinary reinforced masonry shear walls (¹category C limited to 160 ft; not permitted in categories D – F)	2
19. Detailed plain masonry shear walls (¹not permitted in categories C – F)	2
20. Ordinary plain masonry shear walls (¹not permitted in categories C – F)	1.5
21. Prestressed masonry shear walls (¹not permitted in categories C – F)	1.5
22. Light-frame (wood) walls sheathed with wood structural panels rated for shear resistance (¹categories D – F limited to 65 ft)	7
23. Light-frame (cold-formed steel) walls sheathed with wood structural panels rated for shear resistance, or steel sheets (¹categories D – F limited to 65 ft)	7
24. Light framed walls with shear panels — all other materials (¹not permitted in categories E – F; D limited to 35 ft)	2.5
25. Buckling-restrained braced frames (^1,2categories D, E limited to 160 ft; F limited to 100 ft)	8
26. Steel special plate shear walls (^1,2categories D, E limited to 160 ft; F limited to 100 ft)	7

(Part D continued)

Table A-2.6: Seismic coefficients (continued)

D. Response modification coefficient, R (including height and other limitations based on seismic design category¹)
Moment-resisting frame systems
01. Special steel moment frames (no limits)	8
02. Special steel truss moment frames (¹category D limited to 160 ft; E limited to 100 ft; not permitted in category F)	7
03. Intermediate steel moment frames (^1,2category D limited to 35 ft; not permitted in categories E – F)	4.5
04. Ordinary steel moment frames (^1,2not permitted in categories D – F)	3.5
05. Special reinforced concrete moment frames (no limits)	8
06. Intermediate reinforced concrete moment frames (¹not permitted in categories D – F)	5
07. Ordinary reinforced concrete moment frames (¹not permitted in categories C – F)	3
08. Special composite steel and concrete moment frames (no limits)	8
09. Steel and concrete composite intermediate moment frames (¹not permitted in categories D – F)	5
10. Steel and concrete composite partially restrained moment frames (1categories B, C limited to 160 ft; D limited to 100 ft; not permitted in categories E, F)	6
11. Steel and concrete composite ordinary moment frames (¹not permitted in categories C – F)	3
12. Cold-formed steel — special bolted moment frame (1limited to 35 ft in all categories)	3.5
Dual systems with special moment frames that resist at least 25% of seismic forces
01. Steel eccentrically braced frames (no limits)	8
02. Special steel concentrically braced frames (no limits)	7
03. Special reinforced concrete shear walls (no limits)	7
04. Ordinary reinforced concrete shear walls (¹not permitted in categories D – F)	6
05. Composite steel and concrete eccentrically braced frames (no limits)	8
06. Composite steel and concrete special concentrically braced frames (no limits)	6
07. Steel and concrete composite plate shear walls (no limits)	7.5
08. Steel and concrete composite special shear walls with steel elements (no limits)	7
09. Steel and concrete composite ordinary shear walls with steel elements (¹not permitted in categories D – F)	6
10. Special reinforced masonry shear walls (no limits)	5.5
11. Intermediate reinforced masonry shear walls (¹not permitted in categories D – F)	4
12. Buckling-restrained braced frame (no limits)	8

D. Response modification coefficient, R (including height and other limitations based on seismic design category¹)
13. Special steel plate shear walls (no limits)	8
Dual systems with intermediate moment frames that resist at least 25% of seismic forces
01. Special steel concentrically braced frames (¹not permitted in categories E – F; D limited to 35 ft)	6
02. Special reinforced concrete shear walls (¹category D limited to 160 ft; E – F limited to 100 ft)	6.5
03. Ordinary reinforced masonry shear walls (¹category C limited to 160 ft; not permitted in categories D – F)	3
04. Intermediate reinforced masonry shear walls (¹not permitted in categories D – F)	3.5
05. Steel and concrete composite special concentrically braced frames (¹not permitted in category F; D limited to 160 ft; E limited to 100 ft)	5.5
06. Steel and concrete composite ordinary braced frames (¹not permitted in categories D – F)	3.5
07. Steel and concrete composite ordinary shear walls (¹not permitted in categories D – F)	5
08. Ordinary reinforced concrete shear walls (¹not permitted in categories D – F)	5.5
Cantilevered column systems detailed to conform with:
01. Steel special cantilever column systems (¹categories B – F limited to 35 ft)	2.5
02. Steel ordinary cantilever column systems (¹not permitted in categories D – F; B, C limited to 35 ft)	1.25
03. Special reinforced concrete moment frames (¹categories B – F limited to 35 ft)	2.5
04. Intermediate concrete moment frames (¹categories B, C limited to 35 ft; not permitted in categories D – F)	1.5
05. Ordinary concrete moment frames (¹category B limited to 35 ft; not permitted in categories C – F)	1
06. Timber frames (¹categories B – D limited to 35 ft; not permitted in categories E, F)	1.5
Miscellaneous other systems
Steel systems not specifically detailed for seismic resistance, excluding cantilevered column systems (¹not permitted in categories D – F)	3
Shear wall-frame interactive system with ordinary reinforced concrete moment frames and ordinary reinforced concrete shear walls (¹not permitted in categories C – F)	4.5

Notes for Part D:

1. Seismic design categories are described in Table A-2.6 Part G, and range from A (least severe) to F (most severe).

2. Height limits may be increased in certain cases, and buildings may be permitted in certain cases for this seismic force-resisting system (refer to building codes).

Table A-2.6: Seismic coefficients (continued)

E. Fundamental period of vibration, T (seconds) — approximate value, and exponent², k
¹T	Structure	C_T	x
T = C_Th_n^x	Steel moment-resisting frame Concrete moment-resisting frame Steel eccentrically-braced frame and buckling-restrained braced frames All other structural types	0.028 0.016 0.030 0.020	0.8 0.9 0.75 0.75

Notes for Part E:

1. h_n is the building height (ft).

2. k accounts for the more complex effect of longer periods of vibration on the distribution of story forces, and equals 1 for periods ≤ 0.5 seconds; and 2 for periods ≥ 2.5 seconds (with linear interpolation permitted for periods between 0.5 and 2.5 seconds)

F. Importance factor, I_e
Occupancy category	Description	Factor
I	Low hazard (minor storage, etc.)	1.0
II	Regular (ordinary buildings)	1.0
III	Substantial risk to human life or major economic impact, with or without significant disruption of daily life	1.25
IV	Essential facilities (hospitals, fire stations, etc.)	1.50

G. Seismic design category¹
Occupancy category	²0 ≤ S_DS < 0.167 or ²0 ≤ S_D₁ < 0.067	²0.167 ≤ S_DS < 0.33 or 0.067 ≤ S_D₁ < 0.133	²0.33 ≤ S_DS < 0.50 or 1.33 ≤ S_D₁ < 0.02	²0.50 ≤ S_DS or 0.20 ≤ S_D₁	S₁ ≥ 0.75
I	A	B	C	D	E
II	A	B	C	D	E
III	A	B	C	D	E
IV	A	C	D	D	F

Notes for Part G:

1. Where more than one category applies, use the more severe category (i.e., B before A; C before B, etc.)

2. For buildings with S1 < 0.75, it is permissible to use only the S_DS criteria (i.e., one need not consider the criteria involving S_D₁), but only where all of the following apply:

a) T < 0.8S_D₁/S_DS where the period T is found in Table A-2.5 Part E; and S_D₁ and S_DS are found in Table A-2.6 Part C.

b) Floor-roof systems (acting as structural "diaphragms") are concrete slabs or metal decks with concrete infill; or lateral-force-resisting vertical elements (such as shear walls or trusses) are no more than 40 ft apart.

Table A-2.7: Combined load factors¹

A. Strength Design
Load Combinations	Combined Loads and Factors
Dead load	1.4D
Dead, live, and roof or snow	1.2D + 1.6L + 0.5(L_r or S)
Dead, roof or snow, and live² or wind	1.2D + 1.6(L_r or S) + (L or 0.5W)
Dead, wind, live,² and roof or snow	1.2D + 1.0W + L + 0.5(L_r or S)
Dead, earthquake³, live,² and snow	1.2D + 1.0E + L + 0.2S
Dead and wind	0.9D + 1.0W
Dead and earthquake³	0.9D + 1.0E

B. Allowable stress Design
Load Combinations	Combined Loads and Factors
Dead load	D
Dead and live	D + L
Dead and roof or snow	D + (L_r or S)
Dead, live, and roof or snow	D + 0.75L + 0.75(L_r or S)
Dead and wind or earthquake	D + (0.6W or 0.7E)
Dead, live, wind, and roof or snow	D + 0.75L + 0.75(0.6W) + 0.75(L_r or S)
Dead, live, earthquake³, and snow	D + 0.75L + 0.75(0.7E) + 0.75S
Dead and wind	0.6D + 0.6W
Dead and earthquake³	0.6D + 0.7E
Where only D, L, S, and L_r are present the allowable stress load combinations are commonly reduced to the following:
Dead and live	D + L
Dead and roof or snow	D + (L_r or S)
Dead, live, and roof or snow	D + 0.75L + 0.75(L_r or S)

Notes:

1. Only the following loads are considered in this table:

D = dead load; L = live load; L_r = roof live load (construction, maintenance); W = wind load; S = snow load; E = earthquake load (omitted are fluid, flood, lateral earth pressure, rain, and self-straining forces).

2. The load factor for L in these three cases only can be taken as 0.5 when L ≤ 100 psf (except for garages or places of public assembly).

3. The earthquake load effect, E, actually consists of a horizontal and vertical component, E_h and E_v respectively, although the effect of the vertical component can be ignored for buildings in Seismic Design Category B. Where dead, earthquake, live, and snow loads are all combined, the vertical component effect is added to the horizontal component effect, so that E = E_h + E_v. However, it is important to note that for combinations including only dead and earthquake loads, it is the possibility of uplift that must be considered, so that not only is the load factor for the dead load less than 1.0, but the effect of the vertical component of ground motion (earthquake load) is taken to be upwards. In other words, E = E_h – E_v. The vertical component can be taken as E_v = 0.2S_DSD, where values of S_DS can be found in Appendix Table A-2.6 part C; and D is the effect of the dead load on the structural element being analyzed.

Chapter 2 – Loads: Appendix