steel design project - civil engineering

ASCE STANDARD

ASCE/SEI

7-16

Minimum Design Loads and Associated Criteria for Buildings and Other Structures

CHAPTER 2

COMBINATIONS OF LOADS

2.1 GENERAL

Buildings and other structures shall be designed using the provisions of either Section 2.3 or 2.4. Where elements of a structure are designed by a particular material standard or specification, they shall be designed exclusively by either Section 2.3 or 2.4.

2.2 SYMBOLS

Ak = load or load effect arising from extraordinary event A D = dead load Di = weight of ice E = earthquake load F = load caused by fluids with well-defined pressures and

maximum heights Fa = flood load H = load due to lateral earth pressure, ground water pressure, or

pressure of bulk materials L = live load Lr = roof live load N = notional load for structural integrity, Section 1.4 R = rain load S = snow load T = cumulative effect of self-straining forces and effects arising

from contraction or expansion resulting from environmental or operational temperature changes, shrinkage, moisture changes, creep in component materials, movement caused by differential settlement, or combinations thereof

W = wind load Wi = wind-on-ice determined in accordance with Chapter 10

2.3 LOAD COMBINATIONS FOR STRENGTH DESIGN

2.3.1 Basic Combinations. Structures, components, and foundations shall be designed so that their design strength equals or exceeds the effects of the factored loads in the following combinations. Effects of one or more loads not acting shall be considered. Seismic load effects shall be combined loads in accordance with Section 2.3.6. Wind and seismic loads need not be considered to act simultaneously. Refer to Sections 1.4, 2.3.6, 12.4, and 12.14.3 for the specific definition of the earthquake load effect E. Each relevant strength limit state shall be investigated.

1. 1.4D 2. 1.2Dþ 1.6Lþ 0.5(Lr or S or R) 3. 1.2Dþ 1.6(Lr or S or R)þ(L or 0.5W) 4. 1.2Dþ 1.0W þ Lþ 0.5(Lr or S or R) 5. 0.9Dþ 1.0W

EXCEPTIONS:

1. The load factor on L in combinations 3 and 4 is permitted to equal 0.5 for all occupancies in which Lo in Chapter 4, Table 4.3-1, is less than or equal to 100 psf (4.78 kN/sq m), with the exception of garages or areas occupied as places of public assembly.

2. In combinations 2 and 4 the companion load S shall be taken as either the flat roof snow load (pf ) or the sloped roof snow load (ps).

Where fluid loads F are present, they shall be included with the same load factor as dead load D in combinations 1 through 4. Where loads H are present, they shall be included as follows:

1. where the effect of H adds to the principal load effect, include H with a load factor of 1.6;

2. where the effect of H resists the principal load effect, include H with a load factor of 0.9 where the load is permanent or a load factor of 0 for all other conditions.

Effects of one or more loads not acting shall be investigated. The most unfavorable effects from wind loads shall be investi- gated, where appropriate, but they need not be considered to act simultaneously with seismic loads.

Each relevant strength limit state shall be investigated.

2.3.2 Load Combinations Including Flood Load. When a structure is located in a flood zone (Section 5.3.1), the following load combinations shall be considered in addition to the basic combinations in Section 2.3.1:

1. In V-Zones or Coastal A-Zones, 1.0W in combinations 4 and 5 shall be replaced by 1.0W þ 2.0Fa.

2. In noncoastal A-Zones, 1.0W in combinations 4 and 5 shall be replaced by 0.5W þ 1.0Fa

2.3.3 Load Combinations Including Atmospheric Ice Loads. When a structure is subjected to atmospheric ice and wind-on-ice loads, the following load combinations shall be considered:

1. 0.5(Lr or S or R) in combination 2 shall be replaced by 0.2Di þ 0.5S.

2. 1.0W þ 0.5(Lr or S or R) in combination 4 shall be replaced by Di þWi þ 0.5S.

3. 1.0W in combination 5 shall be replaced by Di þWi. 4. 1.0W þ Lþ 0.5(Lr or S or R) in combination 4 shall be

replaced by Di.

2.3.4 Load Combinations Including Self-Straining Forces and Effects. Where the structural effects of T are expected to

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 7

adversely affect structural safety or performance, T shall be considered in combination with other loads. The load factor on T shall be established considering the uncertainty associated with the likely magnitude of the structural forces and effects, the probability that the maximum effect of T will occur simultaneously with other applied loadings, and the potential adverse consequences if the effect of T is greater than assumed. The load factor on T shall not have a value less than 1.0.

2.3.5 Load Combinations for Nonspecified Loads. Where approved by the Authority Having Jurisdiction, the registered design professional is permitted to determine the combined load effect for strength design using a method that is consistent with the method on which the load combination requirements in Section 2.3.1 are based. Such a method must be probability based and must be accompanied by documentation regarding the analysis and collection of supporting data that are acceptable to the Authority Having Jurisdiction.

2.3.6 Basic Combinations with Seismic Load Effects. When a structure is subject to seismic load effects, the following load com- binations shall be considered in addition to the basic combinations in Section 2.3.1. The most unfavorable effects from seismic loads shall be investigated, where appropriate, but they need not be considered to act simultaneously with wind loads.

Where the prescribed seismic load effect, E= f ðEv;EhÞ (defined in Section 12.4.2 or 12.14.3.1) is combined with the effects of other loads, the following seismic load combinations shall be used:

6. 1.2Dþ Ev þ Eh þ Lþ 0.2S 7. 0.9D − Ev þ Eh Where the seismic load effect with overstrength,

Em = f ðEv;EmhÞ, defined in Section 12.4.3, is combined with the effects of other loads, the following seismic load combination for structures shall be used:

6. 1.2Dþ Ev þ Emh þ Lþ 0.2S 7. 0.9D − Ev þ Emh

EXCEPTION:

1. The load factor on L in combinations 6 is permitted to equal 0.5 for all occupancies in which Lo in Chapter 4, Table 4.3-1, is less than or equal to 100 psf (4.78 kN/sqm), with the exception of garages or areas occupied as places of public assembly.

2. In combinations 6, the companion load S shall be taken as either the flat roof snow load (pf ) or the sloped roof snow load (ps).

Where fluid loads F are present, they shall be included with the same load factor as dead load D in combinations 6 and 7.

Where loads H are present, they shall be included as follows:

1. Where the effect of H adds to the primary variable load effect, include H with a load factor of 1.6;

2. Where the effect of H resists the primary variable load effect, include H with a load factor of 0.9 where the load is permanent or a load factor of 0 for all other conditions.

2.4 LOAD COMBINATIONS FOR ALLOWABLE STRESS DESIGN

2.4.1 Basic Combinations. Loads listed herein shall be con- sidered to act in the following combinations; whichever produces the most unfavorable effect in the building, foundation, or structural member shall be considered. Effects of one or more loads not acting shall be considered. Seismic load effects shall be

combined with other loads in accordance with Section 2.4.5. Wind and seismic loads need not be considered to act simultaneously. Refer to Sections 1.4, 2.4.5, 12.4, and 12.14.3 for the specific definition of the earthquake load effect E.

Increases in allowable stress shall not be used with the loads or load combinations given in this standard unless it can be demonstrated that such an increase is justified by structural behavior caused by rate or duration of load.

1. D 2. Dþ L 3. Dþ (Lr or S or R) 4. Dþ 0.75Lþ 0.75(Lr or S or R) 5. Dþ ð0.6WÞ 6. Dþ 0.75Lþ 0.75ð0.6WÞ þ 0.75(Lr or S or R) 7. 0.6Dþ 0.6W

EXCEPTIONS:

1. In combinations 4 and 6, the companion load S shall be taken as either the flat roof snow load (pf ) or the sloped roof snow load (ps).

2. For nonbuilding structures in which the wind load is deter- mined from force coefficients,Cf , identified in Figs. 29.4-1, 29.4-2, and 29.4-3 and the projected area contributing wind force toa foundationelement exceeds1,000 sq ft (93 sqm)on either a vertical or a horizontal plane, it shall be permitted to replace W with 0.9W in combination 7 for design of the foundation, excluding anchorage of the structure to the foundation.

Where fluid loads F are present, they shall be included in combinations 1 through 6 with the same factor as that used for dead load D.

Where loads H are present, they shall be included as follows:

1. where the effect of H adds to the principal load effect, include H with a load factor of 1.0;

2. where the effect of H resists the principal load effect, include H with a load factor of 0.6 where the load is permanent or a load factor of 0 for all other conditions.

The most unfavorable effects from both wind and earthquake loads shall be considered, where appropriate, but they need not be assumed to act simultaneously. Refer to Sections 1.4, 2.4.5, 12.4, and 12.14.3 for the specific definition of the earthquake load effect E.

Increases in allowable stress shall not be used with the loads or load combinations given in this standard unless it can be demonstrated that such an increase is justified by structural behavior caused by rate or duration of load.

2.4.2 Load Combinations Including Flood Load. When a structure is located in a flood zone, the following load combinations shall be considered in addition to the basic combinations in Section 2.4.1:

1. In V-Zones or Coastal A-Zones (Section 5.3.1), 1.5Fa shall be added to other loads in combinations 5, 6, and 7, and E shall be set equal to zero in combinations 5 and 6.

2. In noncoastal A-Zones, 0.75Fa shall be added to combina- tions 5, 6, and 7, and E shall be set equal to zero in combinations 5 and 6.

2.4.3 Load Combinations Including Atmospheric Ice Loads. When a structure is subjected to atmospheric ice and wind-on-ice loads, the following load combinations shall be considered:

1. 0.7Di shall be added to combination 2.

8 STANDARD ASCE/SEI 7-16

2. (Lr or S or R) in combination 3 shall be replaced by 0.7Di þ 0.7Wi þ S.

3. 0.6W in combination 7 shall be replaced by 0.7Di þ 0.7Wi. 4. 0.7Di shall be added to combination 1.

2.4.4 Load Combinations Including Self-Straining Forces and Effects. Where the structural effects of T are expected to adversely affect structural safety or performance, T shall be considered in combination with other loads. Where the maximum effect of load T is unlikely to occur simultaneously with the maximum effects of other variable loads, it shall be permitted to reduce the magnitude of T considered in combination with these other loads. The fraction of T considered in combination with other loads shall not be less than 0.75.

2.4.5 Basic Combinations with Seismic Load Effects. When a structure is subject to seismic load effects, the following load combinations shall be considered in addition to the basic combinations and associated Exceptions in Section 2.4.1.

Where the prescribed seismic load effect, E= f ðEv;EhÞ (de- fined in Section 12.4.2) is combined with the effects of other loads, the following seismic load combinations shall be used:

8. 1.0Dþ 0.7Ev þ 0.7Eh 9. 1.0Dþ 0.525Ev þ 0.525Eh þ 0.75Lþ 0.75S

10. 0.6D − 0.7Ev þ 0.7Eh Where the seismic load effect with overstrength,

Em = f ðEv;EmhÞ, defined in Section 12.4.3, is combined with the effects of other loads, the following seismic load combination for structures not subject to flood or atmospheric ice loads shall be used:

8. 1.0Dþ 0.7Ev þ 0.7Emh 9. 1.0Dþ 0.525Ev þ 0.525Emh þ 0.75Lþ 0.75S

10. 0.6D − 0.7Ev þ 0.7Emh Where allowable stress design methodologies are used with

the seismic load effect defined in Section 12.4.3 and applied in load combinations 8, 9, or 10, allowable stresses are permitted to be determined using an allowable stress increase factor of 1.2. This increase shall not be combined with increases in allowable stresses or load combination reductions otherwise permitted by this standard or the material reference document except for increases caused by adjustment factors in accordance with AWC NDS.

EXCEPTIONS:

1. In combinations 9, the companion load S shall be taken as either the flat roof snow load (pf ) or the sloped roof snow load (ps).

2. It shall be permitted to replace 0.6D with 0.9D in combi- nation 10 for the design of special reinforced masonry shear walls where the walls satisfy the requirement of Section 14.4.2.

Where fluid loads F are present, they shall be included in combinations 8, 9, and 10 with the same factor as that used for dead load D.

Where loads H are present, they shall be included as follows:

1. where the effect of H adds to the primary variable load effect, include H with a load factor of 1.0;

2. where the effect of H resists the primary variable load effect, include H with a load factor of 0.6 where the load is permanent or a load factor of 0 for all other conditions.

2.5 LOAD COMBINATIONS FOR EXTRAORDINARY EVENTS

2.5.1 Applicability. Where required by the owner or applicable code, strength and stability shall be checked to ensure that structures are capable of withstanding the effects of extra- ordinary (i.e., low-probability) events, such as fires, explo- sions, and vehicular impact without disproportionate collapse.

2.5.2 Load Combinations.

2.5.2.1 Capacity. For checking the capacity of a structure or structural element to withstand the effect of an extraordinary event, the following gravity load combination shall be considered:

ð0.9 or 1.2ÞDþ Ak þ 0.5Lþ 0.2S (2.5-1) in which Ak = the load or load effect resulting from extraordinary event A.

2.5.2.2 Residual Capacity. For checking the residual load- carrying capacity of a structure or structural element following the occurrence of a damaging event, selected load-bearing elements identified by the registered design professional shall be notionally removed, and the capacity of the damaged structure shall be evaluated using the following gravity load combination:

ð0.9 or 1.2ÞDþ 0.5Lþ 0.2ðLr or S or RÞ (2.5-2)

2.5.3 Stability Requirements. Stability shall be provided for the structure as a whole and for each of its elements. Any method that considers the influence of second-order effects is permitted.

2.6 LOAD COMBINATIONS FOR GENERAL STRUCTURAL INTEGRITY LOADS

The notional loads, N, specified in Section 1.4 for structural integrity shall be combined with other loads in accordance with Section 2.6.1 for strength design and Section 2.6.2 for allowable stress design.

2.6.1 Strength Design Notional Load Combinations.

1. 1.2Dþ 1.0N þ Lþ 0.2S 2. 0.9Dþ 1.0N

2.6.2 Allowable Stress Design Notional Load Combinations.

1. Dþ 0.7N 2. Dþ 0.75ð0.7NÞ þ 0.75Lþ 0.75(Lr or S or R) 3. 0.6Dþ 0.7N

2.7 CONSENSUS STANDARDS AND OTHER REFERENCED DOCUMENTS

This section lists the consensus standards and other documents that shall be considered part of this standard to the extent referenced in this chapter.

ANSI/AISC 300, Specification for Structural Steel Buildings, American Institute of Steel Construction, 2016.

Cited in: Section 2.3.5 AWC NDS 12, National Design Specification for Wood Con-

struction, Including Supplements, AmericanWood Council, 2012. Cited in: Section 2.4.5 AWC NDS 15, National Design Specification for Wood Con-

struction, Including Supplements, AmericanWood Council, 2014. Cited in: Section 2.4.5

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 9

CHAPTER 4

LIVE LOADS

4.1 DEFINITIONS

The following definitions apply to the provisions of this chapter. FIXED LADDER: A ladder that is permanently attached to a

structure, building, or equipment. GRAB BAR SYSTEM: A bar and associated anchorages and

attachments to the structural system, for the support of body weight in locations such as toilets, showers, and tub enclosures.

GUARDRAIL SYSTEM: A system of components, includ- ing anchorages and attachments to the structural system, near open sides of an elevated surface for the purpose of minimizing the possibility of a fall from the elevated surface by people, equipment, or material.

HANDRAIL SYSTEM: A rail grasped by hand for guidance and support and associated anchorages and attachments to the structural system.

HELIPAD: A structural surface that is used for landing, taking off, taxiing, and parking of helicopters.

LIVE LOAD: A load produced by the use and occupancy of the building or other structure that does not include construction or environmental loads, such as wind load, snow load, rain load, earthquake load, flood load, or dead load.

ROOF LIVE LOAD: A load on a roof produced (1) during maintenance by workers, equipment, and materials, and (2) dur- ing the life of the structure by movable objects, such as planters or other similar small decorative appurtenances that are not occupancy related. An occupancy-related live load on a roof such as rooftop assembly areas, rooftop decks, and vegetative or landscaped roofs with occupiable areas, is considered to be a live load rather than a roof live load.

SCREEN ENCLOSURE: A building or part thereof, in whole or in part self-supporting, having walls and a roof of insect or sun screening using fiberglass, aluminum, plastic, or similar lightweight netting material, which encloses an occupan- cy or use such as outdoor swimming pools, patios or decks, and horticultural and agricultural production facilities.

VEHICLE BARRIER SYSTEM: A system of components, including anchorages and attachments to the structural system near open sides or walls of garage floors or ramps, that acts as a restraint for vehicles.

4.2 LOADS NOT SPECIFIED

For occupancies or uses not designated in this chapter, the live load shall be determined in accordance with a method approved by the Authority Having Jurisdiction.

4.3 UNIFORMLY DISTRIBUTED LIVE LOADS

4.3.1 Required Live Loads. The live loads used in the design of buildings and other structures shall be the maximum loads expected by the intended use or occupancy but shall in no case be

less than the minimum uniformly distributed unit loads required by Table 4.3-1.

4.3.2 Provision for Partitions. In office buildings and in other buildings where partition locations are subject to change, provisions for partition weight shall be made, whether or not partitions are shown on the plans. The partition load shall not be less than 15 psf (0.72 kN∕m2).

EXCEPTION: A partition live load is not required where the minimum specified live load is 80 psf (3.83 kN∕m2) or greater.

4.3.3 Partial Loading. The full intensity of the appropriately reduced live load applied only to a portion of a structure or member shall be accounted for if it produces a more unfavorable load effect than the same intensity applied over the full structure or member. Roof live loads shall be distributed as specified in Table 4.3-1.

4.4 CONCENTRATED LIVE LOADS

Floors, roofs, and other similar surfaces shall be designed to support the uniformly distributed live loads prescribed in Section 4.3 or the concentrated load, in pounds or kilonewtons (kN), given in Table 4.3-1, whichever produces the greater load effects. Unless otherwise specified, the indicated concentration shall be assumed to be uniformly distributed over an area 2.5 ft (762 mm) by 2.5 ft (762 mm) and shall be located so as to produce the maximum load effects in the members.

4.5 LOADS ON HANDRAIL, GUARDRAIL, GRAB BAR, AND VEHICLE BARRIER SYSTEMS, AND ON FIXED LADDERS

4.5.1 Handrail and Guardrail Systems. Handrail and guardrail systems shall be designed to resist a single concentrated load of 200 lb (0.89 kN) applied in any direction at any point on the handrail or top rail to produce the maximum load effect on the element being considered and to transfer this load through the supports to the structure.

4.5.1.1 Uniform Load. Handrail and guardrail systems shall also be designed to resist a load of 50 lb∕ft (pound-force per linear foot) (0.73 kN∕m) applied in any direction along the handrail or top rail and to transfer this load through the supports to the structure. This load need not be assumed to act concurrently with the concentrated load specified in Section 4.5.1.

EXCEPTIONS: The uniform load need not be considered for the following occupancies:

1. one- and two-family dwellings, and 2. factory, industrial, and storage occupancies in areas that are

not accessible to the public and that serve an occupant load not greater than 50.

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 13

Table 4.3-1 Minimum Uniformly Distributed Live Loads, Lo , and Minimum Concentrated Live Loads

Occupancy or Use Uniform, Lo psf (kN∕m2)

Live Load Reduction Permitted?

(Sec. No.)

Multiple-Story Live Load Reduction

Permitted? (Sec. No.) Concentrated

lb (kN) Also See Section

Apartments (See Residential) Access floor systems

Office use 50 (2.40) Yes (4.7.2) Yes (4.7.2) 2,000 (8.90) Computer use 100 (4.79) Yes (4.7.2) Yes (4.7.2) 2,000 (8.90)

Armories and drill rooms 150 (7.18) No (4.7.5) No (4.7.5) Assembly areas

Fixed seats (fastened to floors) 60 (2.87) No (4.7.5) No (4.7.5) Lobbies 100 (4.79) No (4.7.5) No (4.7.5) Movable seats 100 (4.79) No (4.7.5) No (4.7.5) Platforms (assembly) 100 (4.79) No (4.7.5) No (4.7.5) Stage floors 150 (7.18) No (4.7.5) No (4.7.5) Reviewing stands, grandstands, and

bleachers 100 (4.79) No (4.7.5) No (4.7.5) 4.14

Stadiums and arenas with fixed seats (fastened to the floor)

60 (2.87) No (4.7.5) No (4.7.5) 4.14

Other assembly areas 100 (4.79) No (4.7.5) No (4.7.5) Balconies and decks 1.5 times the live load for the

area served. Not required to exceed 100 psf (4.79 kN∕m2)

Yes (4.7.2) Yes (4.7.2)

Catwalks for maintenance access 40 (1.92) Yes (4.7.2) Yes (4.7.2) 300 (1.33) Corridors

First floor 100 (4.79) Yes (4.7.2) Yes (4.7.2) Other floors Same as occupancy served

except as indicated Dining rooms and restaurants 100 (4.79) No (4.7.5) No (4.7.5) Dwellings (See Residential) Elevator machine room grating (on area of

2 in. by 2 in. (50 mm by 50 mm)) — — 300 (1.33)

Finish light floor plate construction (on area of 1 in. by 1 in. (25 mm by 25 mm))

— — 200 (0.89)

Fire escapes 100 (4.79) Yes (4.7.2) Yes (4.7.2) On single-family dwellings only 40 (1.92) Yes (4.7.2) Yes (4.7.2)

Fixed ladders — — See Sec. 4.5.4 Garages (See Section 4.10)

Passenger vehicles only 40 (1.92) No (4.7.4) Yes (4.7.4) See Sec. 4.10.1 Trucks and buses See Sec. 4.10.2 — — See Sec. 4.10.2

Handrails and Guardrails See Sec. 4.5.1 — — See Sec. 4.5.1 Grab bars — — See Sec. 4.5.2

Helipads (See Section 4.11) Helicopter takeoff weight 3,000 lb

(13.35 kN) or less 40 (1.92) No (4.11.1) — See Sec. 4.11.2

Helicopter takeoff weight more than 3,000 lb (13.35 kN)

60 (2.87) No (4.11.1) — See Sec. 4.11.2

Hospitals Operating rooms, laboratories 60 (2.87) Yes (4.7.2) Yes (4.7.2) 1,000 (4.45) Patient rooms 40 (1.92) Yes (4.7.2) Yes (4.7.2) 1,000 (4.45) Corridors above first floor 80 (3.83) Yes (4.7.2) Yes (4.7.2) 1,000 (4.45)

Hotels (See Residential) Libraries

Reading rooms 60 (2.87) Yes (4.7.2) Yes (4.7.2) 1,000 (4.45) Stack rooms 150 (7.18) No (4.7.3) Yes (4.7.3) 1,000 (4.45) 4.13 Corridors above first floor 80 (3.83) Yes (4.7.2) Yes (4.7.2) 1,000 (4.45)

Manufacturing Light 125 (6.00) No (4.7.3) Yes (4.7.3) 2,000 (8.90) Heavy 250 (11.97) No (4.7.3) Yes (4.7.3) 3,000 (13.35)

Office buildings File and computer rooms shall be designed

for heavier loads based on anticipated occupancy

Lobbies and first-floor corridors 100 (4.79) Yes (4.7.2) Yes (4.7.2) 2,000 (8.90) Offices 50 (2.40) Yes (4.7.2) Yes (4.7.2) 2,000 (8.90) Corridors above first floor 80 (3.83) Yes (4.7.2) Yes (4.7.2) 2,000 (8.90)

continues

14 STANDARD ASCE/SEI 7-16

Table 4.3-1. (Continued) Minimum Uniformly Distributed Live Loads, Lo , and Minimum Concentrated Live Loads

Occupancy or Use Uniform, Lo psf (kN∕m2)

Live Load Reduction Permitted?

(Sec. No.)

Multiple-Story Live Load Reduction

Permitted? (Sec. No.) Concentrated

lb (kN) Also See Section

Penal institutions Cell blocks 40 (1.92) Yes (4.7.2) Yes (4.7.2) Corridors 100 (4.79) Yes (4.7.2) Yes (4.7.2)

Recreational uses Bowling alleys, poolrooms, and similar

uses 75 (3.59) No (4.7.5) No (4.7.5)

Dance halls and ballrooms 100 (4.79) No (4.7.5) No (4.7.5) Gymnasiums 100 (4.79) No (4.7.5) No (4.7.5)

Residential One- and two-family dwellings

Uninhabitable attics without storage 10 (0.48) Yes (4.7.2) Yes (4.7.2) 4.12.1 Uninhabitable attics with storage 20 (0.96) Yes (4.7.2) Yes (4.7.2) 4.12.2 Habitable attics and sleeping areas 30 (1.44) Yes (4.7.2) Yes (4.7.2) All other areas except stairs 40 (1.92) Yes (4.7.2) Yes (4.7.2)

All other residential occupancies Private rooms and corridors serving

them 40 (1.92) Yes (4.7.2) Yes (4.7.2)

Public rooms 100 (4.79) No (4.7.5) No (4.7.5) Corridors serving public rooms 100 (4.79) Yes (4.7.2) Yes (4.7.2)

Roofs Ordinary flat, pitched, and curved roofs 20 (0.96) Yes (4.8.2) — 4.8.1 Roof areas used for occupants Same as occupancy served Yes (4.8.3) — Roof areas used for assembly purposes 100 (4.70) Yes (4.8.3) Vegetative and landscaped roofs

Roof areas not intended for occupancy 20 (0.96) Yes (4.8.2) — Roof areas used for assembly purposes 100 (4.70) Yes (4.8.3) — Roof areas used for other occupancies Same as occupancy served Yes (4.8.3) —

Awnings and canopies Fabric construction supported by a

skeleton structure 5 (0.24) No (4.8.2) —

Screen enclosure support frame 5 (0.24) based on the tributary area of the roof supported by the frame member

No (4.8.2) — 200 (0.89)

All other construction 20 (0.96) Yes (4.8.2) — 4.8.1 Primary roof members, exposed to a work floor Single panel point of lower chord of roof 2,000 (8.90)

trusses or any point along primary structural members supporting roofs over manufacturing, storage warehouses, and repair garages

All other primary roof members — — 300 (1.33) All roof surfaces subject to maintenance

workers — — 300 (1.33)

Schools Classrooms 40 (1.92) Yes (4.7.2) Yes (4.7.2) 1,000 (4.45) Corridors above first floor 80 (3.83) Yes (4.7.2) Yes (4.7.2) 1,000 (4.45) First-floor corridors 100 (4.79) Yes (4.7.2) Yes (4.7.2) 1,000 (4.45)

Scuttles, skylight ribs, and accessible ceilings

200 (0.89)

Sidewalks, vehicular driveways, and yards subject to trucking

250 (11.97) No (4.7.3) Yes (4.7.3) 8,000 (35.60) 4.15

Stairs and exit ways 100 (4.79) Yes (4.7.2) Yes (4.7.2) 300 (1.33) 4.16 One- and two-family dwellings only 40 (1.92) Yes (4.7.2) Yes (4.7.2) 300 (1.33) 4.16

Storage areas above ceilings 20 (0.96) Yes (4.7.2) Yes (4.7.2) Storage warehouses (shall be designed for

heavier loads if required for anticipated storage) Light 125 (6.00) No (4.7.3) Yes (4.7.3) Heavy 250 (11.97) No (4.7.3) Yes (4.7.3)

continues

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 15

4.5.1.2 Guardrail System Component Loads. Balusters, panel fillers, and guardrail infill components, including all rails except the handrail and the top rail, shall be designed to resist a horizontally applied normal load of 50 lb (0.22 kN) on an area not to exceed 12 in. by 12 in. (305 mm by 305 mm), including openings and space between rails and located so as to produce the maximum load effects. Reactions due to this loading are not required to be superimposed with the loads specified in Sections 4.5.1 and 4.5.1.1.

4.5.2 Grab Bar Systems. Grab bar systems shall be designed to resist a single concentrated load of 250 lb (1.11 kN) applied in any direction at any point on the grab bar to produce the maximum load effect.

4.5.3 Vehicle Barrier Systems. Vehicle barrier systems for passenger vehicles shall be designed to resist a single load of 6,000 lb (26.70 kN) applied horizontally in any direction to the barrier system and shall have anchorages or attachments capable of transferring this load to the structure. For design of the system, the load shall be assumed to act at heights between 1 ft 6 in. (460 mm) and 2 ft 3 in. (686 mm) above the floor or ramp surface, located to produce the maximum load effects. The load shall be applied on an area not to exceed 12 in. by 12 in. (305 mm by 305 mm). This load is not required to act concurrently with any handrail or guardrail system loadings specified in Section 4.5.1. Vehicle barrier systems in garages accommodating trucks and buses shall be designed in accordance with AASHTO LRFD Bridge Design Specifications.

4.5.4 Fixed Ladders. Fixed ladders with rungs shall be designed to resist a single concentrated load of 300 lb (1.33 kN) applied at any point to produce the maximum load effect on the element being considered. The number and position of additional concentrated live load units shall be a minimum of 1 unit of 300 lb (1.33 kN) for every 10 ft (3.05 m) of ladder height.

Where rails of fixed ladders extend above a floor or platform at the top of the ladder, each side rail extension shall be designed to resist a single concentrated live load of 100 lb (0.445 kN) applied in any direction at any height up to the top of the side rail extension. Ships ladders with treads instead of rungs shall be designed to resist the stair loads given in Table 4.3-1.

4.6 IMPACT LOADS

4.6.1 General. The live loads specified in Sections 4.3 through 4.5 shall be assumed to include adequate allowance for ordinary

impact conditions. Provision shall be made in the structural design for uses and loads that involve unusual vibration and impact forces.

4.6.2 Elevators. All elements subject to dynamic loads from elevators shall be designed for impact loads and deflection limits prescribed by ASME A17.

4.6.3 Machinery. For the purpose of design, the weight of machinery and moving loads shall be increased as follows to allow for impact: (1) light machinery, shaft- or motor-driven, 20%; and (2) reciprocating machinery or power-driven units, 50%. All percentages shall be increased where specified by the manufacturer.

4.6.4 Elements Supporting Hoists for Façade Access and Building Maintenance Equipment. Structural elements that support hoists for façade and building maintenance equipment shall be designed for a live load of 2.5 times the rated load of the hoist or the stall load of the hoist, whichever is larger.

4.6.5 Fall Arrest and Lifeline Anchorages. Fall arrest and lifeline anchorages and structural elements that support these anchorages shall be designed for a live load of 3,100 lb (13.8 kN) for each attached lifeline in every direction that a fall arrest load may be applied.

4.7 REDUCTION IN UNIFORM LIVE LOADS

4.7.1 General. Except for roof uniform live loads, all other minimum uniformly distributed live loads, Lo in Table 4.3-1, are permitted to be reduced in accordance with the requirements of Sections 4.7.2 through 4.7.6.

4.7.2 Reduction in Uniform Live Loads. Subject to the limitations of Sections 4.7.3 through 4.7.6, members for which a value of KLLAT is 400 ft2 (37.16 m2) or more are permitted to be designed for a reduced live load in accordance with the following formula:

L= Lo

� 0.25þ 15ffiffiffiffiffiffiffiffiffiffiffiffiffi

KLLAT p

� (4.7-1)

L= Lo

� 0.25þ 4.57ffiffiffiffiffiffiffiffiffiffiffiffiffi

KLLAT p

� (4.7-1si)

Table 4.3-1. (Continued) Minimum Uniformly Distributed Live Loads, Lo , and Minimum Concentrated Live Loads

Occupancy or Use Uniform, Lo psf (kN∕m2)

Live Load Reduction Permitted?

(Sec. No.)

Multiple-Story Live Load Reduction

Permitted? (Sec. No.) Concentrated

lb (kN) Also See Section

Stores Retail

First floor 100 (4.79) Yes (4.7.2) Yes (4.7.2) 1,000 (4.45) Upper floors 75 (3.59) Yes (4.7.2) Yes (4.7.2) 1,000 (4.45)

Wholesale, all floors 125 (6.00) No (4.7.3) Yes (4.7.3) 1,000 (4.45) Vehicle barriers See Sec. 4.5.3 Walkways and elevated platforms (other

than exit ways) 60 (2.87) Yes (4.7.2) Yes (4.7.2)

Yards and terraces, pedestrian 100 (4.79) No (4.7.5) No (4.7.5)

16 STANDARD ASCE/SEI 7-16

where

L = reduced design live load per ft2 (m2) of area supported by the member

Lo = unreduced design live load per ft2 (m2) of area supported by the member (see Table 4.3-1)

KLL = live load element factor (see Table 4.7-1) AT = tributary area in ft2 (m2).

L shall not be less than 0.50Lo for members supporting one floor, and L shall not be less than 0.40Lo for members supporting two or more floors.

4.7.3 Heavy Live Loads. Live loads that exceed 100 lb∕ft2 (4.79 kN∕m2) shall not be reduced.

EXCEPTION: Live loads for members supporting two or more floors are permitted to be reduced by a maximum of 20%, but the reduced live load shall not be less than L as calculated in Section 4.7.2.

4.7.4 Passenger Vehicle Garages. The live loads shall not be reduced in passenger vehicle garages.

EXCEPTION: Live loads for members supporting two or more floors are permitted to be reduced by a maximum of 20%, but the reduced live load shall not be less than L as calculated in Section 4.7.2.

4.7.5 Assembly Uses. Live loads shall not be reduced in assembly uses.

4.7.6 Limitations on One-Way Slabs. The tributary area, AT , for one-way slabs shall not exceed an area defined by the slab span times a width normal to the span of 1.5 times the slab span.

4.8 REDUCTION IN ROOF LIVE LOADS

4.8.1 General. The minimum uniformly distributed roof live loads, Lo in Table 4.3-1, are permitted to be reduced in accordance with the requirements of Sections 4.8.2 and 4.8.3.

Where uniform roof live loads are reduced to less than 20 lb∕ft2 (0.96 kN∕m2) in accordance with Section 4.8.2 and are applied to the design of structural members arranged so as to create continuity, the reduced roof live load shall be applied to adjacent spans or to alternate spans, whichever produces the greatest unfavorable load effect.

4.8.2 Ordinary Roofs, Awnings, and Canopies. Ordinary flat, pitched, and curved roofs, and awning and canopies other than

those of fabric construction supported by a skeleton structure, are permitted to be designed for a reduced roof live load, as specified in Eq. (4.8-1), or other controlling combinations of loads, as specified in Chapter 2, whichever produces the greater load effect. In structures such as greenhouses, where special scaffolding is used as a work surface for workers and materials during maintenance and repair operations, a lower roof load than specified in Eq. (4.8-1) shall not be used unless approved by the Authority Having Jurisdiction. On such structures, the minimum roof live load shall be 12 psf (0.58 kN∕m2).

Lr =LoR1R2 where 12 ≤ Lr ≤ 20 (4.8-1)

Lr = LoR1R2 where 0.58 ≤ Lr ≤ 0.96 (4.8-1si)

where

Lr = reduced roof live load per ft2 (m2) of horizontal projection supported by the member and

Lo = unreduced design roof live load per ft2 (m2) of horizontal projection supported by the member (see Table 4.3-1).

The reduction factors R1 and R2 shall be determined as follows:

R1 = 1 for AT ≤ 200 ft2 1.2 − 0.001AT for 200 ft2 < AT < 600 ft2 0.6 for AT ≥ 600 ft2

in SI:

R1 = 1 for AT ≤ 18.58 m2 1.2 − 0.011AT for 18.58 m2 < AT < 55.74 m2 0.6 for AT ≥ 55.74 m2

where AT = tributary area in ft2 (m2) supported by the member and

R2 = 1 for F ≤ 4 1.2 − 0.05F for 4 < F < 12 0.6 for F ≥ 12

where, for a pitched roof, F = number of inches of rise per foot (in SI: F = 0.12 × slope, with slope expressed in percentage points) and, for an arch or dome, F = rise-to-span ratio multiplied by 32.

4.8.3 Occupiable Roofs. Roofs that have an occupancy function, such as roof gardens or other special purposes, are permitted to have their uniformly distributed live load reduced in accordance with the requirements of Section 4.7.

Roofs used for other special purposes shall be designed for appropriate loads as approved by the Authority Having Jurisdiction.

4.9 CRANE LOADS

4.9.1 General. The crane live load shall be the rated capacity of the crane. Design loads for the runway beams, including connections and support brackets, of moving bridge cranes and monorail cranes shall include the maximum wheel loads

Table 4.7-1 Live Load Element Factor, KLL

Element KLL a

Interior columns 4 Exterior columns without cantilever slabs 4 Edge columns with cantilever slabs 3 Corner columns with cantilever slabs 2 Edge beams without cantilever slabs 2 Interior beams 2 All other members not identified, including 1

Edge beams with cantilever slabs Cantilever beams One-way slabs Two-way slabs Members without provisions for continuous shear

transfer normal to their span

aIn lieu of the preceding values, KLL is permitted to be calculated.

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 17

CHAPTER 26

WIND LOADS: GENERAL REQUIREMENTS

26.1 PROCEDURES

26.1.1 Scope. Buildings and other structures, including themain wind force resisting system (MWFRS) and all components and cladding (C&C) thereof, shall be designed and constructed to resist the wind loads determined in accordance with Chapters 26 through 31. The provisions of this chapter define basic wind parameters for use with other provisions contained in this standard.

26.1.2 Permitted Procedures. The design wind loads for buildings and other structures, including the MWFRS and C&C elements thereof, shall be determined using one of the procedures as specified in this section. An outline of the overall process for the determination of the wind loads, including section references, is provided in Fig. 26.1-1.

26.1.2.1 Main Wind Force Resisting System. Wind loads for the MWFRS shall be determined using one of the following procedures:

1. Directional Procedure for buildings of all heights as speci- fied in Chapter 27 for buildings meeting the requirements specified therein;

2. Envelope Procedure for low-rise buildings as specified in Chapter 28 for buildings meeting the requirements speci- fied therein;

3. Directional Procedure for Building Appurtenances (rooftop structures and rooftop equipment) and Other Structures (such as solid freestanding walls and solid freestanding signs, chimneys, tanks, open signs, single-plane open frames, and trussed towers) as specified in Chapter 29; or

4. Wind Tunnel Procedure for all buildings and all other structures as specified in Chapter 31.

26.1.2.2 Components and Cladding. Wind loads on C&C on all buildings and other structures shall be designed using one of the following procedures:

1. Analytical Procedures provided in Parts 1 through 6, as appropriate, of Chapter 30; or

2. Wind Tunnel Procedure as specified in Chapter 31.

26.2 DEFINITIONS

The following definitions apply to the provisions of Chapters 26 through 31:

APPROVED: Acceptable to the Authority Having Jurisdiction.

ATTACHED CANOPY: A horizontal (maximum slope of 2%) patio cover attached to the building wall at any height; it is different from an overhang, which is an extension of the roof surface.

BASIC WIND SPEED, V: Three-second gust speed at 33 ft (10 m) above the ground in Exposure C (see Section 26.7.3) as determined in accordance with Section 26.5.1.

BUILDING, ENCLOSED: A building that has the total area of openings in each wall, that receives positive external pressure, less than or equal to 4 sq ft (0.37 m2) or 1% of the area of that wall, whichever is smaller. This condition is expressed for each wall by the following equation:

Ao < 0.01Ag; or 4 sq ft ð0.37 m2Þ;whichever is smaller; where Ao and Ag are as defined for Open Buildings.

BUILDING, LOW-RISE: Enclosed or partially enclosed building that complies with the following conditions:

1. Mean roof height h less than or equal to 60 ft (18 m). 2. Mean roof height h does not exceed least horizontal

dimension.

BUILDING, OPEN: A building that has each wall at least 80% open. This condition is expressed for each wall by the equation Ao ≥ 0.8Ag, where

Ao = total area of openings in a wall that receives positive external pressure, in ft2 (m2); and

Ag = the gross area of that wall in which Ao is identified, in ft2

(m2).

BUILDING, PARTIALLY ENCLOSED: A building that complies with both of the following conditions:

1. The total area of openings in a wall that receives positive external pressure exceeds the sum of the areas of openings in the balance of the building envelope (walls and roof) by more than 10%.

2. The total area of openings in a wall that receives positive external pressure exceeds 4 ft2 (0.37 m2) or 1% of the area of that wall, whichever is smaller, and the percentage of openings in the balance of the building envelope does not exceed 20%.

These conditions are expressed by the following equations:

Ao > 1.10Aoi

Ao > 4 ft2ð0.37 m2Þ or > 0.01Ag; whichever is smaller; andAoi∕Agi ≤ 0.20

where Ao and Ag are as defined for Open Building;

Aoi = sum of the areas of openings in the building envelope (walls and roof) not including Ao, in ft2 (m2); and

Agi = sum of the gross surface areas of the building envelope (walls and roof) not including Ag, in ft2 (m2).

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 245

BUILDING, PARTIALLY OPEN: A building that does not comply with the requirements for open, partially enclosed, or enclosed buildings.

BUILDING, SIMPLE DIAPHRAGM: A building in which both windward and leeward wind loads are transmitted by roof and vertically spanning wall assemblies, through continuous floor and roof diaphragms, to the MWFRS.

BUILDING, TORSIONALLY REGULAR UNDER WIND LOAD: A building with the MWFRS about each princi- pal axis proportioned so that the maximum displacement at each story under Case 2, the torsional wind load case, of Fig. 27.3-8 does not exceed the maximum displacement at the same location under Case 1 of Fig. 27.3-8, the basic wind load case.

BUILDING ENVELOPE: Cladding, roofing, exterior walls, glazing, door assemblies, window assemblies, skylight assem- blies, and other components enclosing the building.

BUILDING OR OTHER STRUCTURE, FLEXIBLE: Slender buildings and other structures that have a fundamental natural frequency less than 1 Hz.

BUILDING OR OTHER STRUCTURE, REGULAR- SHAPED: A building or other structure that has no unusual geometrical irregularity in spatial form.

BUILDING OR OTHER STRUCTURE, RIGID: A build- ing or other structure whose fundamental frequency is greater than or equal to 1 Hz.

COMPONENTS AND CLADDING (C&C): Elements of the building envelope or elements of building appurtenances and

rooftop structures and equipment that do not qualify as part of the MWFRS.

DESIGN FORCE, F: Equivalent static force to be used in the determination of wind loads for other structures.

DESIGN PRESSURE, p: Equivalent static pressure to be used in the determination of wind loads for buildings.

DIAPHRAGM: Roof, floor, or other membrane or bracing system acting to transfer lateral forces to the vertical MWFRS. For analysis under wind loads, diaphragms constructed of untopped steel decks, concrete-filled steel decks, and concrete slabs, each having a span-to-depth ratio of 2 or less, shall be permitted to be idealized as rigid. Diaphragms constructed of wood structural panels are permitted to be idealized as flexible.

DIRECTIONAL PROCEDURE: A procedure for determin- ing wind loads on buildings and other structures for specific wind directions, in which the external pressure coefficients used are based on past wind tunnel testing of prototypical building models for the corresponding direction of wind.

EAVE HEIGHT, he : The distance from the ground surface adjacent to the building to the roof eave line at a particular wall. If the height of the eave varies along the wall, the average height shall be used.

EFFECTIVE WIND AREA, A: The area used to determine the external pressure coefficient, (GCp) and (GCrn). For C&C elements, the effective wind area in Figs. 30.3-1 through 30.3-7, 30.4-1, 30.5-1, and 30.7-1 through 30.7-3 is the span length multiplied by an effective width that need not be less than

Chapter 26—General Requirements: Use to determine the basic parameters for determining wind loads on both the MWFRS and C&C. These basic parameters are

Basic wind speed, V, see Section 26.5; Figs. 26.5-1 and 26.5-2 Wind directionality factor, Kd, see Section 26.6 Exposure, see Section 26.7 Topographic factor, Kzt, see Section 26.8 Ground elevation factor, Ke, see Section 26.9 Velocity pressure, see Section 26.10 Gust-effect factor, see Section 26.11 Enclosure classification, see Section 26.12 Internal pressure coefficient, GCpi, see Section 26.13

Wind loads on the MWFRS may be determined by

Wind loads on the C&C may be determined by

Chapter 27: Directional Procedure for buildings of all heights

Chapter 28: Envelope Procedure for low-rise buildings

Chapter 29: Directional Procedure for building appurtenances (roof overhangs and parapets) and other structures

Chapter 31: Wind Tunnel Procedure for any building or other structure

Chapter 30: - Envelope Procedure in Parts 1 and 2, or - Directional Procedure in Parts 3, 4, and 5 - Building appurtenances (roof overhangs

and parapets) in Part 6 - Nonbuilding structures in Part 7

Chapter 31: Wind Tunnel Procedure for any building or other structure

FIGURE 26.1-1 Outline of Process for Determining Wind Loads

Additional outlines and User Notes are provided at the beginning of each chapter for more detailed step-by-step procedures for determining the wind loads.

246 STANDARD ASCE/SEI 7-16

one-third the span length. For rooftop solar arrays, the effective wind area in Fig. 29.4-7 is equal to the tributary area for the structural element being considered, except that the width of the effective wind area need not be less than one-third its length. For cladding fasteners, the effective wind area shall not be greater than the area that is tributary to an individual fastener.

ENVELOPE PROCEDURE: A procedure for determining wind load cases on buildings, in which pseudoexternal pressure coefficients are derived from past wind tunnel testing of proto- typical building models successively rotated through 360°, such that the pseudopressure cases produce key structural actions (e.g., uplift, horizontal shear, and bending moments) that envelop their maximum values among all possible wind directions.

ESCARPMENT: With respect to topographic effects in Section 26.8, a cliff or steep slope generally separating two levels or gently sloping areas (see Fig. 26.8-1). Also known as a scarp.

FREE ROOF: Roof with a configuration generally conform- ing to those shown in Figs. 27.3-4 through 27.3-6 (monoslope, pitched, or troughed) in an open building with no enclosing walls underneath the roof surface.

GLAZING: Glass or transparent or translucent plastic sheet used in windows, doors, skylights, or curtain walls.

GLAZING, IMPACT-RESISTANT: Glazing that has been shown by testing to withstand the impact of test missiles. See Section 26.12.3.2.

HILL: With respect to topographic effects in Section 26.8, a land surface characterized by strong relief in any horizontal direction (see Fig. 26.8-1).

HURRICANE-PRONE REGIONS: Areas vulnerable to hurricanes; in the United States and its territories, defined as

1. The U.S. Atlantic Ocean and Gulf of Mexico coasts where the basic wind speed for Risk Category II buildings is greater than 115 mi∕h (51.4 m∕s); and

2. Hawaii, Puerto Rico, Guam, Virgin Islands, and American Samoa.

IMPACT-PROTECTIVE SYSTEM: Construction that has been shown by testing to withstand the impact of test missiles and that is applied, attached, or locked over exterior glazing. See Section 26.12.3.2.

MAIN WIND FORCE RESISTING SYSTEM (MWFRS): An assemblage of structural elements assigned to provide support and stability for the overall building or other structure. The system generally receives wind loading from more than one surface.

MEAN ROOF HEIGHT, h: The average of the roof eave height and the height to the highest point on the roof surface, except that, for roof angles less than or equal to 10°, the mean roof height is permitted to be taken as the roof eave height.

OPENINGS: Apertures or holes in the building envelope that allow air to flow through the building envelope and that are designed as “open” during design winds as defined by these provisions.

RECOGNIZED LITERATURE: Published research find- ings and technical papers that are approved.

RIDGE: With respect to topographic effects in Section 26.8, an elongated crest of a hill characterized by strong relief in two directions (see Fig. 26.8-1).

ROOFTOP SOLAR PANEL: A device to receive solar radiation and convert it into electricity or heat energy. Typically this is a photovoltaic module or solar thermal panel.

SOLAR ARRAY: Any number of rooftop solar panels grouped closely together.

WIND-BORNE DEBRIS REGIONS: Areas within hurri- cane-prone regions where impact protection is required for glazed openings; see Section 26.12.3.

WIND TUNNEL PROCEDURE: A procedure for deter- mining wind loads on buildings and other structures, in which pressures and/or forces and moments are determined for each wind direction considered, from a model of the building or other structure and its surroundings, in accordance with Chapter 31.

26.3 SYMBOLS

The following symbols apply only to the provisions of Chapters 26 through 31:

A = effective wind area, in ft2 (m2) Af = area of open buildings and other structures

either normal to the wind direction or pro- jected on a plane normal to the wind direction, in ft2 (m2)

Ag = gross area of that wall in which Ao is identified, in ft2 (m2)

Agi = sum of the gross surface areas of the building envelope (walls and roof) not including Ag, in ft2 (m2)

An = normalized wind area for rooftop solar panels in Fig. 29.4-7

Ao = total area of openings in a wall that receives positive external pressure, in ft2 (m2)

Aog = total area of openings in the building envelope in ft2 (m2)

Aoi = sum of the areas of openings in the building envelope (walls and roof) not including Ao, in ft2 (m2)

As = gross area of the solid freestanding wall or solid sign, in ft2 (m2)

a = width of pressure coefficient zone, in ft (m) B = horizontal dimension of building measured normal

to wind direction, in ft (m) b̄ = mean hourly wind speed factor in Eq. (26.11-16)

from Table 26.11-1 b̂ = 3-s gust speed factor from Table 26.11-1 c = turbulence intensity factor in Eq. (26.11-7) from

Table 26.11-1 Cf = force coefficient to be used in determination of

wind loads for other structures CN = net pressure coefficient to be used in determination

of wind loads for open buildings Cp = external pressure coefficient to be used in determi-

nation of wind loads for buildings D = diameter of a circular structure or member,

in ft (m) D 0 = depth of protruding elements such as ribs and

spoilers, in ft (m) d1 = for rooftop solar arrays, horizontal distance orthog-

onal to the panel edge to an adjacent panel or the building edge, ignoring any rooftop equipment in Fig. 29.4-7, in ft (m)

d2 = for rooftop solar arrays, horizontal distance from the edge of one panel to the nearest edge in the next row of panels in Fig. 29.4-7, in ft (m)

F = design wind force for other structures, in lb (N) G = gust-effect factor Gf = gust-effect factor for MWFRS of flexible buildings

and other structures ðGCpÞ = product of external pressure coefficient and gust-

effect factor to be used in determination of wind loads for buildings

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 247

ðGCpf Þ = product of the equivalent external pressure coeffi- cient and gust-effect factor to be used in determi- nation of wind loads for MWFRS of low-rise buildings

ðGCpiÞ = product of internal pressure coefficient and gust- effect factor to be used in determination of wind loads for buildings

ðGCpn) = combined net pressure coefficient for a parapet ðGCrÞ = product of external pressure coefficient and gust-

effect factor to be used in determination of wind loads for rooftop structures

ðGCrnÞ = net pressure coefficient for rooftop solar panels, in Eqs. (29.4-4) and (29.4-5)

ðGCrnÞnom = nominal net pressure coefficient for rooftop solar panels determined from Fig. 29.4-7

gQ = peak factor for background response in Eqs. (26.11-6) and (26.11-10)

gR = peak factor for resonant response in Eq. (26.11-10) gv = peak factor for wind response in Eqs. (26.11-6) and

(26.11-10) H = height of hill, ridge, or escarpment in Fig. 26.8-1,

in ft (m) h = mean roof height of a building or height of other

structure, except that eave height shall be used for roof angle θ less than or equal to 10°, in ft (m)

h1 = height of a solar panel above the roof at the lower edge of the panel, in ft (m)

h2 = height of a solar panel above the roof at the upper edge of the panel, in ft (m)

he = roof eave height at a particular wall, or the average height if the eave varies along the wall

hp = height to top of parapet in Figs. 27.5-2 and 30.6-1 hpt = mean parapet height above the adjacent roof sur-

face for use with Eq. (29.4-5), in ft (m) Iz̄ = intensity of turbulence from Eq. (26.11-7)

K1, K2, K3 = multipliers in Fig. 26.8-1 to obtain Kzt Kd = wind directionality factor in Table 26.6-1 Ke = Ground elevation factor Kh = velocity pressure exposure coefficient evaluated at

height z= h Kz = velocity pressure exposure coefficient evaluated at

height z Kzt = topographic factor as defined in Section 26.8 L = horizontal dimension of a building measured par-

allel to the wind direction, in ft (m) Lb = normalized building length, for use with

Fig. 29.4-7, in ft (m) Lh = distance upwind of crest of hill, ridge, or escarp-

ment in Fig. 26.8-1 to where the difference in ground elevation is half the height of the hill, ridge, or escarpment, in ft (m)

Lp = panel chord length for use with rooftop solar panels in Fig. 29.4-7, in ft (m)

Lr = horizontal dimension of return corner for a solid freestanding wall or solid sign from Fig. 29.3-1, in ft (m)

Lz = integral length scale of turbulence, in ft (m) l = integral length scale factor from Table 26.11-1,

ft (m) N1 = reduced frequency from Eq. (26.11-14) n1 = fundamental natural frequency, in Hz na = approximate lower bound natural frequency (Hz)

from Section 26.11.2 p = design pressure to be used in determination of

wind loads for buildings, in lb∕ft2 (N∕m2)

PL = wind pressure acting on leeward face in Fig. 27.3-8, in lb∕ft2 (N∕m2)

pnet = net design wind pressure from Eq. (30.4-1), in lb∕ft2 (N∕m2)

pnet30 = net design wind pressure for Exposure B at h= 30 ft (9.1 m) and I = 1.0 from Fig. 30.4-1, in lb∕ft2 (N∕m2)

pp = combined net pressure on a parapet from Eq. (27.3-4), in lb∕ft2 (N∕m2)

ps = net design wind pressure from Eq. (28.5-1), in lb∕ft2 (N∕m2)

ps30 = simplified design wind pressure for Exposure B at h= 30 ft (9.1 m) and I = 1.0 from Fig. 28.5-1, in lb∕ft2 (N∕m2)

PW = wind pressure acting on windward face in Fig. 27.3-8, in lb∕ft2 (N∕m2)

Q = background response factor from Eq. (26.11-8) q = velocity pressure, in lb∕ft2 (N∕m2) qh = velocity pressure evaluated at height z= h, in lb∕ft2

(N∕m2) qi = velocity pressure for internal pressure determina-

tion, in lb∕ft2 (N∕m2) qp = velocity pressure at top of parapet, in lb∕ft2 (N∕m2) qz = velocity pressure evaluated at height z above

ground, in lb∕ft2 (N∕m2) R = resonant response factor from Eq. (26.11-12) r = rise-to-span ratio for arched roofs

RB;Rh;RL = values from Eqs. (26.11-15a) and (26.11-15b) Ri = reduction factor from Eq. (26.13-1) Rn = value from Eq. (26.11-13) s = vertical dimension of the solid freestanding wall or

solid sign from Fig. 29.3-1, in ft (m) V = basic wind speed obtained from Figs. 26.5-1A

through 26.5-1D and 26.5-2A through 26.5-2D, in mi∕h (m∕s). The basic wind speed corresponds to a 3-s gust speed at 33 ft (10 m) above the ground in Exposure Category C

Vi = unpartitioned internal volume, in ft3 (m3) V̄ z̄ = mean hourly wind speed at height z̄, in ft∕s (m∕s) W = width of building in Figs. 30.3-3, 30.3-5A, and

30.3-5B and width of span in Figs. 30.3-4 and 30.3-6, in ft (m)

WL = width of a building on its longest side in Fig. 29.4-7, in ft (m)

WS = width of a building on its shortest side in Fig. 29.4-7, in ft (m)

x = distance upwind or downwind of crest in Fig. 26.8-1, in ft (m)

z = height above ground level, in ft (m) z̄ = equivalent height of structure, in ft (m) zg = nominal height of the atmospheric boundary

layer used in this standard (values appear in Table 26.11-1)

zmin = exposure constant from Table 26.11-1 α = 3-s gust-speed power law exponent from

Table 26.11-1 α̂ = reciprocal of α from Table 26.11-1 ᾱ = mean hourly wind-speed power law exponent in

Eq. (26.11-16) from Table 26.11-1 β = damping ratio, percent critical for buildings or

other structures γc = panel chord factor for use with rooftop solar panels

in Eq. (29.4-5) γE = array edge factor for use with rooftop solar panels

in Fig. 29.4-7 and Eqs. (29.4-4) and (29.4-5)

248 STANDARD ASCE/SEI 7-16

γp = parapet height factor for use with rooftop solar panels in Eq. (29.4-5)

ε = ratio of solid area to gross area for solid freestand- ing wall, solid sign, open sign, face of a trussed tower, or lattice structure

ε̄ = integral length scale power law exponent in Eq. (26.11-9) from Table 26.11-1

η = value used in Eqs. (26.11-15a) and (26.11-15b) (see Section 26.11.4)

θ = angle of plane of roof from horizontal, in degrees λ = adjustment factor for building height and exposure

from Figs. 28.5-1 and 30.4-1 v = height-to-width ratio for solid sign ω = angle that the solar panel makes with the roof

surface in Fig. 29.4-7, in degrees

26.4 GENERAL

26.4.1 Sign Convention. Positive pressure acts toward the surface and negative pressure acts away from the surface.

26.4.2 Critical Load Condition. Values of external and internal pressures shall be combined algebraically to determine the most critical load.

26.4.3 Wind Pressures Acting on Opposite Faces of Each Building Surface. In the calculation of design wind loads for the MWFRS and for C&C for buildings, the algebraic sum of the pressures acting on opposite faces of each building surface shall be taken into account.

26.5 WIND HAZARD MAP

26.5.1 Basic Wind Speed. The basic wind speed, V , used in the determination of design wind loads on buildings and other structures shall be determined from Figs. 26.5-1 and 26.5-2 as follows, except as provided in Sections 26.5.2 and 26.5.3:

For Risk Category I buildings and structures, use Figs. 26.5-1A and 26.5-2A.

For Risk Category II buildings and structures, use Figs. 26.5-1B and 26.5-2B.

For Risk Category III buildings and structures, use Figs. 26.5-1C and 26.5-2C.

For Risk Category IV buildings and structures, use Figs. 26.5-1D and 26.5-2D.

The wind shall be assumed to come from any horizontal direction. The basic wind speed shall be increased where records or experience indicate that the wind speeds are higher than those reflected in Figs. 26.5-1 and 26.5-2.

26.5.2 Special Wind Regions. Mountainous terrain, gorges, and special wind regions shown in Fig. 26.5-1 shall be examined for unusual wind conditions. The Authority Having Jurisdiction shall, if necessary, adjust the values given in Fig. 26.5-1 to account for higher local wind speeds. Such adjustment shall be based on meteorological information and an estimate of the basic wind speed obtained in accordance with the provisions of Section 26.5.3.

26.5.3 Estimation of Basic Wind Speeds from Regional Climatic Data. In areas outside hurricane-prone regions, regional climatic data shall only be used in lieu of the basic wind speeds given in Figs. 26.5-1 and 26.5-2 when (1) approved extreme-value statistical analysis procedures have been used in reducing the data; and (2) the length of record, sampling error, averaging time, anemometer height, data quality, and terrain exposure of the anemometer have been taken into account. Reduction in basic wind speed below that of Figs. 26.5-1 and 26.5-2 shall be permitted.

In hurricane-prone regions, wind speeds derived from simula- tion techniques shall only be used in lieu of the basic wind speeds given in Figs. 26.5-1 and 26.5-2 when approved simulation and extreme-value statistical analysis procedures are used. The use of regional wind speed data obtained from anemometers is not permitted to define the hurricane wind-speed risk along the Gulf and Atlantic coasts, the Caribbean, or Hawaii.

When the basic wind speed is estimated from regional climatic data or simulation, the estimate shall correspond to the applicable mean recurrence interval, and the estimate shall be adjusted for equivalence to a 3-s gust wind speed at 33 ft (10 m) above ground in Exposure C.

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 249

Notes

1. Values are nominal design 3-s gust wind speeds in mi/h (m∕s) at 33 ft (10 m) above ground for Exposure Category C. 2. Linear interpolation is permitted between contours. Point values are provided to aid with interpolation. 3. Islands, coastal areas, and land boundaries outside the last contour shall use the last wind speed contour. 4. Mountainous terrain, gorges, ocean promontories, and special wind regions shall be examined for unusual wind conditions. 5. Wind speeds correspond to approximately a 15% probability of exceedance in 50 years (Annual Exceedance Probability = 0.00333, MRI= 300 years). 6. Location-specific basic wind speeds shall be permitted to be determined using www.atcouncil.org/windspeed.

FIGURE 26.5-1A Basic Wind Speeds for Risk Category I Buildings and Other Structures

continues

250 STANDARD ASCE/SEI 7-16

FIGURE 26.5-1A (Continued ). Basic Wind Speeds for Risk Category I Buildings and Other Structures

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 251

Notes

1. Values are nominal design 3-s gust wind speeds in mi/h (m∕s) at 33 ft (10 m) above ground for Exposure Category C. 2. Linear interpolation is permitted between contours. Point values are provided to aid with interpolation. 3. Islands, coastal areas, and land boundaries outside the last contour shall use the last wind speed contour. 4. Mountainous terrain, gorges, ocean promontories, and special wind regions shall be examined for unusual wind conditions. 5. Wind speeds correspond to approximately a 7% probability of exceedance in 50 years (Annual Exceedance Probability = 0.00143, MRI= 700 years). 6. Location-specific basic wind speeds shall be permitted to be determined using www.atcouncil.org/windspeed.

FIGURE 26.5-1B Basic Wind Speeds for Risk Category II Buildings and Other Structures

continues

252 STANDARD ASCE/SEI 7-16

FIGURE 26.5-1B (Continued ). Basic Wind Speeds for Risk Category II Buildings and Other Structures

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 253

Notes

1. Values are nominal design 3-s gust wind speeds in mi/h (m∕s) at 33 ft (10 m) above ground for Exposure Category C. 2. Linear interpolation is permitted between contours. Point values are provided to aid with interpolation. 3. Islands, coastal areas, and land boundaries outside the last contour shall use the last wind speed contour. 4. Mountainous terrain, gorges, ocean promontories, and special wind regions shall be examined for unusual wind conditions. 5. Wind speeds correspond to approximately a 3% probability of exceedance in 50 years (Annual Exceedance Probability = 0.000588, MRI= 1,700 years). 6. Location-specific basic wind speeds shall be permitted to be determined using www.atcouncil.org/windspeed.

FIGURE 26.5-1C Basic Wind Speeds for Risk Category III Buildings and Other Structures

continues

254 STANDARD ASCE/SEI 7-16

FIGURE 26.5-1C (Continued ). Basic Wind Speeds for Risk Category III Buildings and Other Structures

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 255

Notes

1. Values are nominal design 3-s gust wind speeds in mi/h (m∕s) at 33 ft (10 m) above ground for Exposure Category C. 2. Linear interpolation is permitted between contours. Point values are provided to aid with interpolation. 3. Islands, coastal areas, and land boundaries outside the last contour shall use the last wind speed contour. 4. Mountainous terrain, gorges, ocean promontories, and special wind regions shall be examined for unusual wind conditions. 5. Wind speeds correspond to approximately a 1.6% probability of exceedance in 50 years (Annual Exceedance Probability = 0.00033, MRI= 3,000 years). 6. Location-specific basic wind speeds shall be permitted to be determined using www.atcouncil.org/windspeed.

FIGURE 26.5-1D Basic Wind Speeds for Risk Category IV Buildings and Other Structures

continues

256 STANDARD ASCE/SEI 7-16

FIGURE 26.5-1D (Continued ). Basic Wind Speeds for Risk Category IV Buildings and Other Structures

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 257

Notes

1. Values are nominal design 3-s gust wind speeds in mi/h (m∕s) at 33 ft (10 m) above ground for Exposure Category C. Metric conversion: 1 mph= 0.45 m/s. 2. Linear interpolation between contours is permitted. 3. Islands and coastal areas outside the last contour shall use the last wind speed contour of the coastal area. 4. It is permitted to use the standard values of Kztof 1.0 and Kdas given in Table 26.6-1. 5. Ocean promontories and local escarpments shall be examined for unusual wind conditions. 6. Wind speeds correspond to approximately a 15% probability of exceedance in 50 years (Annual Exceedance Probability = 0.00333, MRI= 300 years)

FIGURE 26.5-2A Basic Wind Speeds for Risk Category I Buildings and Other Structures: Hawaii

continues

258 STANDARD ASCE/SEI 7-16

FIGURE 26.5-2A (Continued ). Basic Wind Speeds for Risk Category I Buildings and Other Structures: Hawaii

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 259

Notes

1. Values are nominal design 3-s gust wind speeds in mi/h (m∕s) at 33 ft (10 m) above ground for Exposure Category C. Metric conversion: 1 mph= 0.45 m/s. 2. Linear interpolation between contours is permitted. 3. Islands and coastal areas outside the last contour shall use the last wind speed contour of the coastal area. 4. It is permitted to use the standard values of Kzt of 1.0 and Kd as given in Table 26.6-1. 5. Ocean promontories and local escarpments shall be examined for unusual wind conditions. 6. Wind speeds correspond to approximately a 7% probability of exceedance in 50 years (Annual Exceedance Probability = 0.00143, MRI= 700 years).

FIGURE 26.5-2B Basic Wind Speeds for Risk Category II Buildings and Other Structures: Hawaii

continues

260 STANDARD ASCE/SEI 7-16

FIGURE 26.5-2B (Continued ). Basic Wind Speeds for Risk Category II Buildings and Other Structures: Hawaii

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 261

Notes

1. Values are nominal design 3-s gust wind speeds in mi/h (m∕s) at 33 ft (10 m) above ground for Exposure Category C. Metric conversion: 1 mph= 0.45 m/s. 2. Linear interpolation between contours is permitted. 3. Islands and coastal areas outside the last contour shall use the last wind speed contour of the coastal area. 4. It is permitted to use the standard values of Kzt of 1.0 and Kd as given in Table 26.6-1. 5. Ocean promontories and local escarpments shall be examined for unusual wind conditions. 6. Wind speeds correspond to approximately a 3% probability of exceedance in 50 years (Annual Exceedance Probability = 0.000588, MRI= 1,700 years).

FIGURE 26.5-2C Basic Wind Speeds for Risk Category III Buildings and Other Structures: Hawaii

continues

262 STANDARD ASCE/SEI 7-16

FIGURE 26.5-2C (Continued ). Basic Wind Speeds for Risk Category III Buildings and Other Structures: Hawaii

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 263

Notes

1. Values are nominal design 3-s gust wind speeds in mi/h (m∕s) at 33 ft (10 m) above ground for Exposure Category C. Metric conversion: 1 mph= 0.45 m/s. 2. Linear interpolation between contours is permitted. 3. Islands and coastal areas outside the last contour shall use the last wind speed contour of the coastal area. 4. It is permitted to use the standard values of Kzt of 1.0 and Kd as given in Table 26.6-1. 5. Ocean promontories and local escarpments shall be examined for unusual wind conditions. 6. Wind speeds correspond to approximately a 1.7% probability of exceedance in 50 years (Annual Exceedance Probability = 0.000333, MRI= 3,000 years).

FIGURE 26.5-2D Basic Wind Speeds for Risk Category IV Buildings and Other Structures: Hawaii

continues

264 STANDARD ASCE/SEI 7-16

FIGURE 26.5-2D (Continued ). Basic Wind Speeds for Risk Category IV Buildings and Other Structures: Hawaii

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 265

26.6 WIND DIRECTIONALITY

The wind directionality factor, Kd, shall be determined from Table 26.6-1 and shall be included in the wind loads calculated in Chapters 27 to 30. The effect of wind directionality in determining wind loads in accordance with Chapter 31 shall be based on a rational analysis of the wind speeds conforming to the requirements of Section 26.5.3 and of Section 31.4.3.

26.7 EXPOSURE

For each wind direction considered, the upwind exposure shall be based on ground surface roughness that is determined from natural topography, vegetation, and constructed facilities.

26.7.1 Wind Directions and Sectors. For each selected wind direction at which the wind loads are to be determined, the exposure of the building or structure shall be determined for the two upwind sectors extending 45° on either side of the selected wind direction. The exposure in these two sectors shall be determined in accordance with Sections 26.7.2 and 26.7.3, and the exposure the use of which would result in the highest wind loads shall be used to represent the winds from that direction.

26.7.2 Surface Roughness Categories. A ground surface roughness within each 45° sector shall be determined for a distance upwind of the site, as defined in Section 26.7.3, from the categories defined in the following text, for the purpose of assigning an exposure category as defined in Section 26.7.3.

Surface Roughness B: Urban and suburban areas, wooded areas, or other terrain with numerous, closely spaced obstructions that have the size of single-family dwellings or larger.

Surface Roughness C: Open terrain with scattered obstruc- tions that have heights generally less than 30 ft (9.1 m). This category includes flat, open country and grasslands.

Surface Roughness D: Flat, unobstructed areas and water surfaces. This category includes smooth mud flats, salt flats, and unbroken ice.

26.7.3 Exposure Categories. Exposure B: For buildings or other structures with a mean roof height less than or equal to 30 ft (9.1 m), Exposure B shall apply where the ground surface roughness, as defined by Surface Roughness B, prevails in the upwind direction for a distance greater than 1,500 ft (457 m). For buildings or other structures with a mean roof height greater than 30 ft (9.1 m), Exposure B shall apply where Surface Roughness B prevails in the upwind direction for a distance greater than 2,600 ft (792 m) or 20 times the height of the building or structure, whichever is greater.

Exposure C: Exposure C shall apply for all cases where Exposure B or D does not apply.

Exposure D: Exposure D shall apply where the ground surface roughness, as defined by Surface Roughness D, prevails in the upwind direction for a distance greater than 5,000 ft (1,524 m) or 20 times the building or structure height, whichever is greater. Exposure D shall also apply where the ground surface roughness immediately upwind of the site is B or C, and the site is within a distance of 600 ft (183 m) or 20 times the building or structure height, whichever is greater, from an Exposure D condition as defined in the previous sentence.

For a site located in the transition zone between exposure categories, the category resulting in the largest wind forces shall be used.

EXCEPTION: An intermediate exposure between the pre- ceding categories is permitted in a transition zone, provided that it is determined by a rational analysis method defined in the recognized literature.

26.7.4 Exposure Requirements.

26.7.4.1 Directional Procedure (Chapter 27). For each wind direction considered, wind loads for the design of the MWFRS of enclosed and partially enclosed buildings using the Directional Procedure of Chapter 27 shall be based on the exposures as defined in Section 26.7.3. Wind loads for the design of open buildings with monoslope, pitched, or troughed free roofs shall be based on the exposures, as defined in Section 26.7.3, resulting in the highest wind loads for any wind direction at the site.

26.7.4.2 Envelope Procedure (Chapter 28). Wind loads for the design of the MWFRS for all low-rise buildings designed using the Envelope Procedure of Chapter 28 shall be based on the exposure category resulting in the highest wind loads for any wind direction at the site.

26.7.4.3 Directional Procedure for Building Appurtenances and Other Structures (Chapter 29). Wind loads for the design of building appurtenances (such as rooftop structures and equipment) and other structures (such as solid freestanding walls and freestanding signs, chimneys, tanks, open signs, single-plane open frames, and trussed towers) as specified in Chapter 29 shall be based on the appropriate exposure for each wind direction considered.

26.7.4.4 Components and Cladding (Chapter 30). Design wind pressures for C&C shall be based on the exposure category resulting in the highest wind loads for any wind direction at the site.

26.8 TOPOGRAPHIC EFFECTS

26.8.1 Wind Speed-Up over Hills, Ridges, and Escarpments. Wind speed-up effects at isolated hills, ridges, and escarpments constituting abrupt changes in the general topography, located in any exposure category, shall be included in the determination of the wind loads when site

Table 26.6-1 Wind Directionality Factor, Kd

Structure Type Directionality Factor Kd

Buildings Main Wind Force Resisting System 0.85 Components and Cladding 0.85

Arched Roofs 0.85 Circular Domes 1.0a

Chimneys, Tanks, and Similar Structures Square 0.90 Hexagonal 0.95 Octagonal 1.0a

Round 1.0a

Solid Freestanding Walls, Roof Top Equipment, and Solid Freestanding and Attached Signs

0.85

Open Signs and Single-Plane Open Frames 0.85 Trussed Towers Triangular, square, or rectangular 0.85 All other cross sections 0.95

a

Directionality factor Kd = 0.95 shall be permitted for round or octagonal structures with nonaxisymmetric structural systems.

266 STANDARD ASCE/SEI 7-16

Topographic Multipliers for Exposure Ca,b,c

K 1 Multiplier

x∕Lh

K 2 Multiplier

z∕Lh

K 2 Multiplier

H∕Lh 2D Ridge 2D Escarpment 3D Axisym- metrical Hill 2D Escarpment

All Other Cases 2D Ridge 2D Escarpment

3D Axisym- metrical Hill

0.20 0.29 0.17 0.21 0.00 1.00 1.00 0.00 1.00 1.00 1.00 0.25 0.36 0.21 0.26 0.50 0.88 0.67 0.10 0.74 0.78 0.67 0.30 0.43 0.26 0.32 1.00 0.75 0.33 0.20 0.55 0.61 0.45 0.35 0.51 0.30 0.37 1.50 0.63 0.00 0.30 0.41 0.47 0.30 0.40 0.58 0.34 0.42 2.00 0.50 0.00 0.40 0.30 0.37 0.20 0.45 0.65 0.38 0.47 2.50 0.38 0.00 0.50 0.22 0.29 0.14 0.50 0.72 0.43 0.53 3.00 0.25 0.00 0.60 0.17 0.22 0.09

3.50 0.13 0.00 0.70 0.12 0.17 0.06 4.00 0.00 0.00 0.80 0.09 0.14 0.04

0.90 0.07 0.11 0.03 1.00 0.05 0.08 0.02 0.50 0.01 0.02 0.00 2.00 0.00 0.00 0.00

aFor values of H∕Lh, x∕Lh, and z∕Lh other than those shown, linear interpolation is permitted.bFor H∕Lh > 0.5, assume that H∕Lh = 0.5 for evaluating K1 and substitute 2H for Lh for evaluating K2 and K3.cMultipliers are based on the assumption that wind approaches the hill or escarpment along the direction of maximum slope.

Notation

H = Height of hill or escarpment relative to the upwind terrain, in ft (m). K1 = Factor to account for shape of topographic feature and maximum speed-up effect. K2 = Factor to account for reduction in speed-up with distance upwind or downwind of crest. K3 = Factor to account for reduction in speed-up with height above local terrain. Lh = Distance upwind of crest to where the difference in ground elevation is half the height of hill or escarpment, in ft (m). x = Distance (upwind or downwind) from the crest to the site of the building or other structure, in ft (m). z = Height above ground surface at the site of the building or other structure, in ft (m). μ = Horizontal attenuation factor. γ = Height attenuation factor.

Equations

Kzt = ð1þ K1K2K3Þ2 K1 = determined from table below K2 = ð1 − jxj∕μLhÞ K3 = e−yz∕Lh

Parameters for Speed-Up over Hills and Escarpments

Hill Shape

K 1∕ðH∕Lh Þ

γ

μ

Exposure

Upwind of Crest Downwind of CrestB C D

2D ridges (or valleys with negative H in K1∕ðH∕LhÞ 1.30 1.45 1.55 3 1.5 1.5 2D escarpments 0.75 0.85 0.95 2.5 1.5 4 3D axisymmetrical hill 0.95 1.05 1.15 4 1.5 1.5

FIGURE 26.8-1 Topographic Factor, Kzt

Diagrams

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 267

conditions and locations of buildings and other structures meet all of the following conditions:

1. The hill, ridge, or escarpment is isolated and unobstructed upwind by other similar topographic features of comparable height for 100 times the height of the topographic feature (100H) or 2 mi (3.22 km), whichever is less. This distance shall be measured horizontally from the point at which the height H of the hill, ridge, or escarpment is determined.

2. The hill, ridge, or escarpment protrudes above the height of upwind terrain features within a 2-mi (3.22-km) radius in any quadrant by a factor of 2 or more.

3. The building or other structure is located as shown in Fig. 26.8-1 in the upper one-half of a hill or ridge or near the crest of an escarpment.

4. H∕Lh ≥ 0.2. 5. H is greater than or equal to 15 ft (4.5 m) for Exposure C

and D and 60 ft (18 m) for Exposure B.

26.8.2 Topographic Factor. The wind speed-up effect shall be included in the calculation of design wind loads by using the factor Kzt:

Kzt = ð1þ K1K2K3Þ2 (26.8-1) where K1, K2, and K3 are given in Fig. 26.8-1.

If site conditions and locations of buildings and other struc- tures do not meet all the conditions specified in Section 26.8.1, then Kzt = 1.0.

26.9 GROUND ELEVATION FACTOR

The ground elevation factor to adjust for air density, Ke, shall be determined in accordance with Table 26.9-1. It is permitted to take Ke = 1 for all elevations.

26.10 VELOCITY PRESSURE

26.10.1 Velocity Pressure Exposure Coefficient. Based on the exposure category determined in Section 26.7.3, a velocity pressure exposure coefficient, Kz or Kh, as applicable, shall be determined from Table 26.10-1. For a site located in a transition zone between exposure categories that is near to a change in ground surface roughness, intermediate values of Kz or Kh,

between those shown in Table 26.10-1 are permitted provided that they are determined by a rational analysis method defined in the recognized literature.

26.10.2 Velocity Pressure. Velocity pressure, qz, evaluated at height z above ground shall be calculated by the following equation:

qz = 0.00256KzKztKdKeV2 ðlb∕ft2Þ; V inmi∕h (26.10-1)

qz = 0.613KzKztKdKeV2 ðN∕m2Þ; V inm∕s (26.10-1.si) where

Kz = velocity pressure exposure coefficient, see Section 26.10.1. Kzt = topographic factor, see Section 26.8.2. Kd = wind directionality factor, see Section 26.6. Ke = ground elevation factor, see Section 26.9. V = basic wind speed, see Section 26.5. qz = velocity pressure at height z.

The velocity pressure at mean roof height is computed as qh = qz evaluated from Eq. (26.10-1) using Kz at mean roof height h.

The basic wind speed, V , used in determination of design wind loads on rooftop structures, rooftop equipment, and other

Table 26.9-1 Ground Elevation Factor, Ke

Ground Elevation above Sea Level Ground Elevation

Factor ft m Ke

<0 <0 See note 2 0 0 1.00 1,000 305 0.96 2,000 610 0.93 3,000 914 0.90 4,000 1,219 0.86 5,000 1,524 0.83 6,000 1,829 0.80 >6,000 >1,829 See note 2

Notes 1. The conservative approximation Ke = 1.00 is permitted in all cases. 2. The factor Ke shall be determined from the above table using interpo-

lation or from the following formula for all elevations: Ke=e−0.0000362zg (zg = ground elevation above sea level in ft). Ke = e−0.000119zg (zg = ground elevation above sea level in m).

3. Ke is permitted to be take as 1.00 in all cases.

Table 26.10-1 Velocity Pressure Exposure Coefficients, Kh and Kz

Height above Ground Level, z Exposure

ft m B C D

0–15 0–4.6 0.57 (0.70)a 0.85 1.03 20 6.1 0.62 (0.70)a 0.90 1.08 25 7.6 0.66 (0.70)a 0.94 1.12 30 9.1 0.70 0.98 1.16 40 12.2 0.76 1.04 1.22 50 15.2 0.81 1.09 1.27 60 18.0 0.85 1.13 1.31 70 21.3 0.89 1.17 1.34 80 24.4 0.93 1.21 1.38 90 27.4 0.96 1.24 1.40 100 30.5 0.99 1.26 1.43 120 36.6 1.04 1.31 1.48 140 42.7 1.09 1.36 1.52 160 48.8 1.13 1.39 1.55 180 54.9 1.17 1.43 1.58 200 61.0 1.20 1.46 1.61 250 76.2 1.28 1.53 1.68 300 91.4 1.35 1.59 1.73 350 106.7 1.41 1.64 1.78 400 121.9 1.47 1.69 1.82 450 137.2 1.52 1.73 1.86 500 152.4 1.56 1.77 1.89

aUse 0.70 in Chapter 28, Exposure B, when z < 30 ft (9.1 m). Notes

1. The velocity pressure exposure coefficient Kz may be determined from the following formula: For 15 ft ð4.6 mÞ ≤ z ≤ zg Kz = 2.01ðz∕zgÞ2∕α For z < 15 ft ð4.6 mÞ Kz = 2.01ð15∕zgÞ2∕α

2. α and zg are tabulated in Table 26.11-1. 3. Linear interpolation for intermediate values of height z is acceptable. 4. Exposure categories are defined in Section 26.7.

268 STANDARD ASCE/SEI 7-16

building appurtenances shall consider the Risk Category equal to the greater of the following:

1. Risk Category for the building on which the equipment or appurtenance is located or

2. Risk Category for any facility to which the equipment or appurtenance provides a necessary service.

26.11 GUST EFFECTS

26.11.1 Gust-Effect Factor. The gust-effect factor for a rigid building or other structure is permitted to be taken as 0.85.

26.11.2 Frequency Determination. To determine whether a building or other structure is rigid or flexible as defined in Section 26.2, the fundamental natural frequency, n1, shall be established using the structural properties and deformational characteristics of the resisting elements in a properly substantiated analysis. Low-rise buildings, as defined in Section 26.2, are permitted to be considered rigid.

26.11.2.1 Limitations for Approximate Natural Frequency. As an alternative to performing an analysis to determine n1, the approximate building natural frequency, na, shall be permitted to be calculated in accordance with Section 26.11.3 for structural steel, concrete, or masonry buildings meeting the following requirements:

1. The building height is less than or equal to 300 ft (91 m), and 2. The building height is less than 4 times its effective length, Leff .

The effective length, Leff , in the direction under consideration shall be determined from the following equation:

Leff =

Xn i= 1

hiLi

Xn i= 1

hi

(26.11-1)

The summations are over the height of the building where

hi = height above grade of level i; and Li = building length at level i parallel to the wind direction.

26.11.3 Approximate Natural Frequency. The approximate lower bound natural frequency (na), in hertz, of concrete or stru- ctural steel buildings meeting the conditions of Section 26.11.2.1 is permitted to be determined from one of the following equations:

For structural steel moment-resisting frame buildings,

na = 22.2∕h0.8 (26.11-2) For concrete moment-resisting frame buildings,

na = 43.5∕h0.9 (26.11-3)

For structural steel and concrete buildings with other lateral- force-resisting systems,

na = 75∕h (26.11-4)

For concrete or masonry shear wall buildings, it is also permitted to use

na = 385ðCwÞ0.5∕h (26.11-5) where

Cw = 100 AB

Xn i= 1

� h

hi

� 2 Ai ½1þ 0.83ðhiDiÞ

2� where

h = mean roof height, ft (m). n = number of shear walls in the building effective in resisting

lateral forces in the direction under consideration. AB = base area of the building, ft

2 (m2). Ai = horizontal cross-sectional area of shear wall i, ft2 (m2). Di = length of shear wall i, ft (m). hi = height of shear wall i, ft (m).

26.11.4 Rigid Buildings or Other Structures. For rigid buildings or other structures as defined in Section 26.2, the gust- effect factor shall be taken as 0.85 or calculated by this formula:

G= 0.925 � 1þ 0.7gQIz̄Q 1þ 0.7gvIz̄

� (26.11-6)

Iz̄ = c � 33 z̄

� 1∕6

(26.11-7)

Iz̄ = c � 10 z̄

� 1∕6

(26.11-7.si)

where Iz̄ = intensity of turbulence at height z̄, where z̄ is the equivalent height of the building or structure defined as 0.6h, but not less than zmin for all building or structure heights h. zmin and c are listed for each exposure in Table 26.11-1; gQ and gv shall be taken as 3.4. The background response Q is given by

Table 26.11-1 Terrain Exposure Constants

Customary Units

Exposure α zg (ft) α̂ b̂ ᾱ b̄ c l (ft) ∈̄ zmin (ft)a

B 7.0 1,200 1∕70 0.84 1∕4.0 0.45 0.30 320 1∕3.0 30 C 9.5 900 1∕9.5 1.00 1∕6.5 0.65 0.20 500 1∕5.0 15 D 11.5 700 1∕11.5 1.07 1∕9.0 0.80 0.15 650 1∕8.0 7

S.I. Units

Exposure α zg (m) α̂ b̂ ᾱ b̄ c l (m) ∈̄ zmin (m)a

B 7.0 365.76 1∕7 0.84 1∕4.0 0.45 0.30 97.54 1∕3.0 9.14 C 9.5 274.32 1∕9.5 1.00 1∕6.5 0.65 0.20 152.40 1∕5.0 4.57 D 11.5 213.36 1∕11.5 1.07 1∕9.0 0.80 0.15 198.12 1∕8.0 2.13 azmin = minimum height used to ensure that the equivalent height z̄ is the greater of 0.6h or zmin. For buildings or other structures with h ≤ zmin, z̄ shall be taken as zmin.

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 269

Q=

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1

1þ 0.63 �

Bþ h Lz̄

� 0.63

vuuut (26.11-8)

where B and h are defined in Section 26.3; and Lz̄ = integral length scale of turbulence at the equivalent height given by

Lz̄ =l �

z̄

33

� ε̄

(26.11-9)

Lz̄ =l �

z̄

10

� ε̄

(26.11-9.si)

in which l and ε̄ = constants listed in Table 26.11-1.

26.11.5 Flexible or Dynamically Sensitive Buildings or Other Structures. For flexible or dynamically sensitive buildings or other structures as defined in Section 26.2, the gust-effect factor shall be calculated by

Gf = 0.925 �1þ 1.7Iz̄ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffig2QQ2 þ g2RR2q

1þ 1.7gvIz̄

� (26.11-10)

gQ and gv shall be taken as 3.4, and gR is given by

gR = ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 2 lnð3,600n1Þ

p þ 0.577ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

2 lnð3,600n1Þ p (26.11-11)

R, the resonant response factor, is given by

R=

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1 β RnRhRBð0.53þ 0.47RLÞ

s (26.11-12)

Rn = 7.47N1

ð1þ 10.3N1Þ5∕3 (26.11-13)

N1 = n1Lz̄ V̄ z̄

(26.11-14)

Rl = 1 η −

1

2η2 ð1 − e−2ηÞ for η > 0 (26.11-15a)

Rl = 1 for η= 0 (26.11-15b)

where the subscript l in Eqs. (26.11-15a) and (26.11-15b) shall be taken as h, B, and L, respectively, where h, B, and L are defined in Section 26.3, and

n1 = fundamental natural frequency. Rl = Rh setting η= 4.6n1h∕V̄ z̄. Rl = RB setting η= 4.6n1B∕V̄ z̄. Rl = RL setting η= 15.4n1L∕V̄ z̄; β = damping ratio, percent of critical (i.e., for 2% use 0.02 in the

equation). V̄ z̄ = mean hourly wind speed (ft∕s) (m∕s) at height z̄ determined

from Eq. (26.11-16):

V̄ z̄ = b̄ �

z̄

33

� ᾱ � 88 60

� V (26.11-16)

V̄ z̄ = b̄ �

z̄

10

� ᾱ V (26.11-16.si)

where b̄ and ᾱ are constants listed in Table 26.9-1; and V is the basic wind speed in mi∕h (m∕s).

26.11.6 Rational Analysis. In lieu of the procedure defined in Sections 26.11.4 and 26.11.5, determination of the gust-effect factor by any rational analysis defined in the recognized literature is permitted.

26.11.7 Limitations. Where combined gust-effect factors and pressure coefficients (GCp), (GCpi), and (GCpf ) are given in figures and tables, the gust-effect factor shall not be determined separately.

26.12 ENCLOSURE CLASSIFICATION

26.12.1 General. For the purpose of determining internal pressure coefficients, all buildings shall be classified as enclosed, partially enclosed, partially open, or open as defined in Section 26.2.

26.12.2 Openings. A determination shall be made of the amount of openings in the building envelope for use in determining the enclosure classification. To make this determination, each building wall shall be assumed as the windward wall for consideration of the amount of openings present with respect to the remaining building envelope.

26.12.3 Protection of Glazed Openings. Glazed openings in Risk Category II, III, or IV buildings located in hurricane-prone regions shall be protected as specified in this section.

26.12.3.1 Wind-Borne Debris Regions. Glazed openings shall be protected in accordance with Section 26.12.3.2 in the following locations:

1. Within 1 mi (1.6 km) of the coastal mean high water line where the basic wind speed is equal to or greater than 130 mi∕h (58 m∕s), or

2. In areas where the basic wind speed is equal to or greater than 140 mi∕h (63 m∕s).

For Risk Category II buildings and other structures and Risk Category III buildings and other structures, except health-care facilities, the wind-borne debris region shall be based on Figs. 26.5-1B and 26.5-2B. For Risk Category III health-care facilities, the wind-borne debris region shall be based on Figs. 26.5-1C and 26.5-2C. For Risk Category IV buildings and structures, the wind- borne debris region shall be based on Figs. 26.5-1D and 26.5-2D. Risk Categories shall be determined in accordance with Section 1.5.

EXCEPTION: Glazing located more than 60 ft (18.3 m) above the ground and more than 30 ft (9.2 m) above aggregate- surfaced roofs, including roofs with gravel or stone ballast, located within 1,500 ft (458 m) of the building shall be permitted to be unprotected.

26.12.3.2 Protection Requirements for Glazed Openings. Glazing in buildings requiring protection shall be protected with an impact-protective system or shall be impact-resistant glazing.

Impact-protective systems and impact-resistant glazing shall be subjected to missile test and cyclic pressure differential tests in accordance with ASTM E1996 as applicable. Testing to demon- strate compliance with ASTM E1996 shall be in accordance with ASTM E1886. Impact-resistant glazing and impact-protective sys- tems shall comply with the pass/fail criteria of Section 7 of ASTM E1996 based on the missile required by Table 3 or Table 4 of ASTM E1996. Glazing in sectional garage doors and rolling doors shall be subjected to missile tests and cyclic pressure differential tests in accordance with ANSI/DASMA 115 as applicable.

270 STANDARD ASCE/SEI 7-16

EXCEPTION: Other testing methods and/or performance criteria are permitted to be used when approved.

Glazing and impact-protective systems in buildings and other structures classified as Risk Category IV in accordance with Section 1.5 shall comply with the “enhanced protection” require- ments of Table 3 of ASTM E1996. Glazing and impact-protective systems in all other structures shall comply with the “basic protection” requirements of Table 3 of ASTM E1996.

26.12.4 Multiple Classifications. If a building by definition complies with both the “open” and “partially enclosed” definitions, it shall be classified as an “open” building.

26.13 INTERNAL PRESSURE COEFFICIENTS

Internal pressure coefficients, (GCpi), shall be determined from Table 26.13-1 based on building enclosure classifications deter- mined from Section 26.12.

26.13.1 Reduction Factor for Large-Volume Buildings, Ri . For a partially enclosed building containing a single, unpartitioned large volume, the internal pressure coefficient, (GCpi), shall be multiplied by the following reduction factor, Ri:

Ri = 1.0 or

Ri = 0.5

0 B@1þ 1ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

1þ Vi22,800Aog q

1 CA < 1.0 (26.13-1)

where

Aog = total area of openings in the building envelope (walls and roof, in ft2); and

Vi = unpartitioned internal volume, in ft3.

26.14 TORNADO LIMITATION

Tornadoes have not been considered in the wind load provisions.

26.15 CONSENSUS STANDARDS AND OTHER REFERENCED DOCUMENTS

This section lists the consensus standards and other documents that shall be considered part of this standard to the extent referenced in this chapter.

AAMA 512, Voluntary Specifications for Tornado Hazard Mitigating Fenestration Products, American Architectural Man- ufacturers Association, 2011.

Cited in: C26.14.4 ANSI A58.1,Minimum Design Loads for Buildings and Other

Structures, American National Standards Institute, 1982. Cited in: Section C26.5.2 ASTM E1886, Standard test method for performance of

exterior windows, curtain walls, doors, and impact protective systems impacted by missile(s) and exposed to cyclic pressure differentials, ASTM International, 2013.

Cited in: Section 26.12.3.2, C26.12, C26.14.4. ASTM E1996, Standard specification for performance of

exterior windows, curtain walls, doors, and impact protective systems impacted by windborne debris in hurricanes, ASTM International, 2014.

Cited in: Section 26.12.3.2, C26.12, C26.14.4. ANSI/DASMA 115, Standard Method for Testing Sectional

Garage Doors: Determination of Structural Performance under Missile Impact and Cyclic Wind Pressure, Door and Access Systems Manufacturers Association International, 2005.

Cited in: Section 26.12.3.2, C26.12. ASTME330, Standard Test Method for Structural Performance

of Exterior Windows, Doors, Skylights, and Curtain Walls by Uniform Static Air Pressure Difference, ASTM International, 2014.

Cited in: Section C26.5.1 CAN/CSA A123.21, Standard test method for the dynamic wind

uplift resistance of membrane-roofing systems, CSA Group, 2014. Cited in: Section C26.5.1 ICC 500, ICC/NSSA Standard for the Design and Construc-

tion of Storm Shelters, International Code Council and National Storm Shelter Association, 2014.

Cited in: Section C26.14.1, C26.14.3, C26.14.4

Table 26.13-1 Main Wind Force Resisting System and Components and Cladding (All Heights): Internal Pressure Coefficient, (GCpi ), for Enclosed, Partially Enclosed, Partially Open, and Open Buildings (Walls and Roof)

Enclosure Classification Criteria for Enclosure Classification Internal Pressure Internal Pressure Coefficient, (GCpi )

Enclosed buildings Ao is less than the smaller of 0.01Ag or 4 sq ft (0.37 m) and Aoi∕Agi ≤ 0.2

Moderate þ0.18 −0.18

Partially enclosed buildings Ao > 1.1Aoi and Ao > the lesser of 0.01Ag or 4 sq ft (0.37 m) and Aoi∕Agi ≤ 0.2

High þ0.55 −0.55

Partially open buildings A building that does not comply with Enclosed, Partially Enclosed, or Open classifications

Moderate þ0.18 −0.18

Open buildings Each wall is at least 80% open Negligible 0.00

Notes 1. Plus and minus signs signify pressures acting toward and away from the internal surfaces, respectively. 2. Values of (GCpi) shall be used with qz or qh as specified. 3. Two cases shall be considered to determine the critical load requirements for the appropriate condition:

a. A positive value of (GCpi) applied to all internal surfaces, or b. A negative value of (GCpi) applied to all internal surfaces.

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 271

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CHAPTER 27

WIND LOADS ON BUILDINGS: MAIN WIND FORCE RESISTING SYSTEM (DIRECTIONAL PROCEDURE)

27.1 SCOPE

27.1.1 Building Types. This chapter applies to the determina- tion of main wind force resisting system (MWFRS) wind loads on enclosed, partially enclosed, and open buildings of all heights using the Directional Procedure.

Part 1 applies to buildings of all heights where it is necessary to separate applied wind loads onto the windward, leeward, and sidewalls of the building to properly assess the internal forces in the MWFRS members.

Part 2 applies to a special class of buildings designated as enclosed simple diaphragm buildings, as defined in Section 26.2, with h ≤ 160 ft (h ≤ 48.8 m).

27.1.2 Conditions. A building that has design wind loads determined in accordance with this chapter shall comply with all of the following conditions:

1. The building is a regular-shaped building as defined in Section 26.2, and

2. The building does not have response characteristics that make it subject to across-wind loading, vortex shedding, or instability caused by galloping or flutter; nor does it have a site location for which channeling effects or buffet- ing in the wake of upwind obstructions warrant special consideration.

27.1.3 Limitations. The provisions of this chapter take into consideration the load magnification effect caused by gusts in resonance with along-wind vibrations of flexible buildings. Buildings that do not meet the requirements of Section 27.1.2 or that have unusual shapes or response characteristics shall be designed using recognized literature documenting such wind load effects or shall use the Wind Tunnel Procedure specified in Chapter 31.

27.1.4 Shielding. There shall be no reductions in velocity pressure caused by apparent shielding afforded by buildings and other structures or terrain features.

27.1.5 Minimum Design Wind Loads. The wind load to be used in the design of the MWFRS for an enclosed or partially enclosed building shall not be less than 16 lb∕ ft2

(0.77 kN∕m2) multiplied by the wall area of the building, and 8 lb∕ ft2 (0.38 kN∕m2) multiplied by the roof area of the building projected onto a vertical plane normal to the assumed wind direction. Wall and roof loads shall be applied simultaneously. The design wind force for open buildings shall be not less than 16 lb∕ ft2 (0.77 kN∕m2) multiplied by the area, Af .

PART 1: ENCLOSED, PARTIALLY ENCLOSED, AND OPEN BUILDINGS OF ALL HEIGHTS

User Note: Use Part 1 of Chapter 27 to determine wind pressures on the MWFRS of enclosed, partially enclosed, or open buildings with any general plan shape, building height, or roof geometry that matches the figures provided. These provisions use the traditional “all heights” method (Direc- tional Procedure) by calculating wind pressures using specific wind pressure equations applicable to each building surface.

27.2 GENERAL REQUIREMENTS

The steps to determine the wind loads on the MWFRS for enclosed, partially enclosed, and open buildings of all heights are provided in Table 27.2-1.

Table 27.2-1 Steps to Determine MWFRS Wind Loads for Enclosed, Partially Enclosed, and Open Buildings of All Heights

Step 1: Determine Risk Category of building; see Table 1.5-1. Step 2: Determine the basic wind speed, V , for the applicable Risk Category;

see Figs. 26.5-1 and 26.5-2. Step 3: Determine wind load parameters:

• Wind directionality factor, Kd ; see Section 26.6 and Table 26.6-1. • Exposure category; see Section 26.7. • Topographic factor, Kzt; see Section 26.8 and table in Fig. 26.8-1. • Ground elevation factor, Ke; see Section 26.9 • Gust-effect factor, G or Gf ; see Section 26.11. • Enclosure classification; see Section 26.12. • Internal pressure coefficient, (GCpi); see Section 26.13 and

Table 26.13-1. Step 4: Determine velocity pressure exposure coefficient, Kz or Kh; see

Table 26.10-1. Step 5: Determine velocity pressure qz or qh, Eq. (26.10-1). Step 6: Determine external pressure coefficient, Cp or CN :

• Fig. 27.3-1 for walls and flat, gable, hip, monoslope, or mansard roofs. • Fig. 27.3-2 for domed roofs. • Fig. 27.3-3 for arched roofs. • Fig. 27.3-4 for monoslope roof, open building. • Fig. 27.3-5 for pitched roof, open building. • Fig. 27.3-6 for troughed roof, open building. • Fig. 27.3-7 for along-ridge/valley wind load case for monoslope,

pitched, or troughed roof, open building. Step 7: Calculate wind pressure, p, on each building surface:

• Eq. (27.3-1) for rigid and flexible buildings. • Eq. (27.3-2) for open buildings.

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 273

27.2.1 Wind Load Parameters Specified in Chapter 26. The following wind load parameters shall be determined in accordance with Chapter 26:

• Basic wind speed, V (Section 26.5). • Wind directionality factor, Kd (Section 26.6). • Exposure category (Section 26.7). • Topographic factor, Kzt (Section 26.8). • Ground elevation factor, Ke; see Section 26.9 • Gust-effect factor (Section 26.11). • Enclosure classification (Section 26.12). • Internal pressure coefficient, (GCpi) (Section 26.13).

27.3 WIND LOADS: MAIN WIND FORCE RESISTING SYSTEM

27.3.1 Enclosed and Partially Enclosed Rigid and Flexible Buildings. Design wind pressures for the MWFRS of buildings of all heights in lb ∕ ft2 ðN ∕m2Þ, shall be determined by the following equation:

p= qGCp − qiðGCpiÞ (27.3-1) where

q = qz for windward walls evaluated at height z above the ground.

q = qh for leeward walls, sidewalls, and roofs evaluated at height h.

qi = qh for windward walls, sidewalls, leeward walls, and roofs of enclosed buildings, and for negative internal pressure evaluation in partially enclosed buildings.

qi = qz for positive internal pressure evaluation in partially enclosed buildings where height z is defined as the level of the highest opening in the building that could affect the positive internal pressure. For buildings sited in wind-borne debris regions, glazing that is not impact- resistant or protected with an impact-resistant covering shall be treated as an opening in accordance with Section 26.12.3. For positive internal pressure evaluation, qi may conservatively be evaluated at height hðqi = qhÞ.

G = gust-effect factor; see Section 26.11. For flexible build- ings, Gf determined in accordance with Section 26.11.5 shall be substituted for G.

Cp = external pressure coefficient from Figs. 27.3-1, 27.3-2, and 27.3-3.

(GCpi) = internal pressure coefficient from Table 26.13-1.

Both q and qi shall be evaluated using exposure defined in Section 26.7.3. Pressure shall be applied simultaneously on windward and leeward walls and on roof surfaces as defined in Figs. 27.3-1, 27.3-2, and 27.3-3.

27.3.2 Open Buildings with Monoslope, Pitched, or Troughed Free Roofs. The net design pressure for the MWFRS of open buildings with monoslope, pitched, or troughed free roofs in lb ∕ ft2 ðN ∕m2Þ, shall be determined by the following equation:

p= qhGCN (27.3-2)

where

qh = velocity pressure evaluated at mean roof height h using the exposure as defined in Section 26.7.3 that results in the highest wind loads for any wind direction at the site.

G = gust-effect factor from Section 26.11. CN = net pressure coefficient determined from Figs. 27.3-4

through 27.3-7.

Net pressure coefficients, CN , include contributions from top and bottom surfaces. All load cases shown for each roof angle shall be investigated. Plus and minus signs signify pressure acting toward and away from the top surface of the roof, respectively.

For free roofs with an angle of plane of roof from horizontal θ less than or equal to 5° and containing fascia panels, the fascia panel shall be considered an inverted parapet. The contribution of loads on the fascia to the MWFRS loads shall be determined using Section 27.3.5, with qp equal to qh. For an open or partially enclosed building with transverse frames and a pitched roof (θ ≤ 45°), an additional horizontal force in the longitudinal direction (parallel to the ridge) that acts in combination with the roof load calculated in Section 27.3.3 shall be determined in accordance with Section 28.3.5.

27.3.3 Roof Overhangs. The positive external pressure on the bottom surface of windward roof overhangs shall be determined using Cp = 0.8 and combined with the top surface pressures determined using Fig. 27.3-1.

27.3.4 Parapets. The design wind pressure for the effect of parapets on MWFRS of rigid or flexible buildings with flat, gable, or hip roofs in lb ∕ ft2 ðN ∕m2Þ, shall be determined by the following equation:

pp = qpðGCpnÞðlb∕ ft2Þ (27.3-3) where

pp = combined net pressure on the parapet caused by the combination of the net pressures from the front and back parapet surfaces. Plus (and minus) signs signify net pressure acting toward (and away from) the front (exterior) side of the parapet.

qp = velocity pressure evaluated at the top of the parapet. (GCpn) = combined net pressure coefficient:

=þ1.5 for windward parapet or = −1.0 for leeward parapet.

27.3.5 Design Wind Load Cases. The MWFRS of buildings of all heights, the wind loads of which have been determined under the provisions of this chapter, shall be designed for the wind load cases as defined in Fig. 27.3-8.

EXCEPTION: Buildings meeting the requirements of Section D1.1 of Appendix D need only be designed for Case 1 and Case 3 of Fig. 27.3-8.

The eccentricity e for rigid buildings shall be measured from the geometric center of the building face and shall be considered for each principal axis (eX , eY ). The eccentricity e for flexible buildings shall be determined from the following equation and shall be considered for each principal axis (eX , eY ):

e= eQ þ 1.7Iz̄

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ðgQQeQÞ2 þ ðgRReRÞ2

q 1þ 1.7Iz̄

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ðgQQÞ2 þ ðgRRÞ2

q (27.3-4)

where

eQ = eccentricity e as determined for rigid buildings in Fig. 27.3-8. eR = distance between the elastic shear center and center of mass

of each floor. Iz, gQ, Q, gR, and R shall be as defined in Section 26.11.

The sign of the eccentricity e shall be plus or minus, whichever causes the more severe load effect.

274 STANDARD ASCE/SEI 7-16

Diagrams

Notation B = Horizontal dimension of building, in ft (m), measured normal to wind direction. L = Horizontal dimension of building, in ft (m), measured parallel to wind direction. h =Mean roof height, in ft (m), except that eave height shall be used for θ ≤ 10 degrees. z = Height above ground, in ft (m). G = Gust-effect factor.

qz, qh = Velocity pressure, in lb∕ ft 2 (N∕m2), evaluated at respective height.

θ = Angle of plane of roof from horizontal, in degrees.

FIGURE 27.3-1 Main Wind Force Resisting System, Part 1 (All Heights): External Pressure Coefficients, Cp , for Enclosed and Partially Enclosed Buildings—Walls and Roofs

continues

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 275

Wall Pressure Coefficients, Cp

Surface L∕B Cp Use With

Windward wall All values 0.8 qz 0–1 −0.5 qh

Leeward wall 2 −0.3 qh ≥4 −0.2 qh

Sidewall All values −0.7 qh

Roof Pressure Coefficients, Cp, for use with qh

Windward Leeward

Wind Direction

Angle, θ (degrees) Angle, θ (degrees)

h∕L 10 15 20 25 30 35 45 ≥60c 10 15 ≥20

Normal to Ridge for θ ≥ 10°

≤0.25 −0.7 −0.5 −0.3 −0.2 −0.2 0.0a

−0.18 0.0a 0.2 0.3 0.3 0.4 0.4 0.01 θ −0.3 −0.5 −0.6 0.5 −0.9 −0.7 −0.4 −0.3 −0.2 −0.2 0.0a

−0.18 −0.18 0.0a 0.2 0.2 0.3 0.4 0.01 θ −0.5 −0.5 −0.6 ≥1.0 −1.3b −1.0 −0.7 −0.5 −0.3 −0.2 0.0a

−0.18 −0.18 −0.18 0.0a 0.2 0.2 0.3 0.01 θ −0.7 −0.6 −0.6

Wind Direction h/L Horizontal Distance from Windward Edge Cp

Normal to Ridge for θ < 10° and Parallel to Ridge for All θ

≤0.5 0 to h∕ 2 −0.9, −0.18 h∕ 2 to h −0.9, −0.18 h to 2h −0.5, −0.18 >2 h −0.3, −0.18

≥1.0 0 to h∕ 2 −1.3b, −0.18 >h∕ 2 −0.7, −0.18

aValue is provided for interpolation purposes. bValue can be reduced linearly with area over which it is applicable as follows: cFor roof slopes greater than 80°, use Cp = 0.8.

Area, ft2 Area, m2 Reduction Factor

≤100 ≤9.3 1.0 250 23.2 0.9 ≥1,000 ≥92.9 0.8

Notes

1. Plus and minus signs signify pressures acting toward and away from the surfaces, respectively. 2. Linear interpolation is permitted for values of L∕B, h∕ L, and θ other than shown. Interpolation shall only be carried out between

values of the same sign. Where no value of the same sign is given, assume 0.0 for interpolation purposes. 3. Where two values of Cp are listed, this indicates that the windward roof slope is subjected to either positive or negative pressures

and the roof structure shall be designed for both conditions. Interpolation for intermediate ratios of h∕ L in this case shall only be carried out between Cp values of like sign.

4. For monoslope roofs, entire roof surface is either a windward or leeward surface. 5. Refer to Fig. 27.3-2 for domes and Fig. 27.3-3 for arched roofs. 6. For mansard roofs, the top horizontal surface and leeward inclined surface shall be treated as leeward surfaces from

the table. 7. Except for MWFRSs at the roof consisting of moment-resisting frames, the total horizontal shear shall not be less than that

determined by neglecting wind forces on roof surfaces.

FIGURE 27.3-1 (Coninued ). Main Wind Force Resisting System, Part 1 (All Heights): External Pressure Coefficients, Cp , for Enclosed and Partially Enclosed Buildings—Walls and Roofs

276 STANDARD ASCE/SEI 7-16

Notation f = Dome rise, in ft (m).

hD = Height to base of dome, in ft (m). D = Diameter, in ft (m). θ = Angle of plane of roof from horizontal, in degrees.

Notes

1. Two load cases shall be considered: Case A: Cp values between A and B and between B and C shall be determined by linear interpolation along arcs on the dome

parallel to the wind direction; Case B: Cp shall be the constant value of A for θ ≤ 25 degrees and shall be determined by linear interpolation from 25 degrees to

B and from B to C. 2. Values denote Cp to be used with qðhDþf Þ where hDþf is the height at the top of the dome. 3. Plus and minus signs signify pressures acting toward and away from the surfaces, respectively. 4. Cp is constant on the dome surface for arcs of circles perpendicular to the wind direction; for example, the arc passing through

B−B−B and all arcs parallel to B−B−B. 5. For values of hD∕D between those listed on the graph curves, linear interpolation shall be permitted. 6. θ= 0 degrees on dome springline, θ= 90 degrees at dome center top point. f is measured from springline to top. 7. The total horizontal shear shall not be less than that determined by neglecting wind forces on roof surfaces. 8. For f ∕D values less than 0.05, use Fig. 27.3-1.

FIGURE 27.3-2 Main Wind Force Resisting System, Part 1 (All Heights): External Pressure Coefficients, Cp , for Enclosed and Partially Enclosed Buildings and Structures—Domed Roofs with a Circular Base

Diagrams

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 277

External Pressure Coefficient, Cp

Conditions Rise-to-Span Ratio, r

Cp

Windward Quarter Center Half Leeward Quarter

Roof on elevated structure 0 < r < 0.2 −0.9 −0.7 − r −0.5 0.2 ≤ r < 0.3a 1.5r − 0.3 −0.7 − r 0.5 0.3 ≤ r ≤ 0.6 2.75r − 0.7 −0.7 − r 0.5

Roof springing from ground level 0 < r ≤ 0.6 1.4r −0.7 − r 0.5 aWhen the rise-to-span ratio is 0.2 ≤ r ≤ 0.3, alternate coefficients given by 6r − 2.1 shall also be used for the windward quarter.

Notes

1. Values listed are for the determination of average loads on main wind-force resisting systems. 2. Plus and minus signs signify pressures acting toward and away from the surfaces, respectively. 3. For wind directed parallel to the axis of the arch, use pressure coefficients from Fig. 27.3-1 with wind directed parallel to ridge. 4. For components and cladding (1) at roof perimeter, use the external pressure coefficients in Fig. 30.3-2A, B, and C with θ based

on springline slope and (2) for remaining roof areas, use external pressure coefficients of this table multiplied by 1.2.

FIGURE 27.3-3 Main Wind Force Resisting System and Components and Cladding, Part 1 (All Heights): External Pressure Coefficients, Cp , for Enclosed and Partially Enclosed Buildings and Structures—Arched Roofs

278 STANDARD ASCE/SEI 7-16

Diagrams

Notation L = Horizontal dimension of roof, measured in the along-wind direction, ft (m). h =Mean roof height, ft (m). γ = Direction of wind, degrees. θ = Angle of plane of roof from horizontal, degrees.

Net Pressure Coefficient, CN

Roof Angle, θ Load Case

Wind Direction, γ=0° Wind Direction, γ =180°

Clear Wind Flow Obstructed Wind Flow Clear Wind Flow Obstructed Wind Flow

CNW CNL CNW CNL CNW CNL CNW CNL

0° A 1.2 0.3 −0.5 −1.2 1.2 0.3 −0.5 −1.2 B −1.1 −0.1 −1.1 −0.6 −1.1 −0.1 −1.1 −0.6

7.5° A −0.6 −1.0 −1.0 −1.5 0.9 1.5 –0.2 −1.2 B −1.4 0.0 −1.7 −0.8 1.6 0.3 0.8 −0.3

15° A −0.9 −1.3 −1.1 −1.5 1.3 1.6 0.4 −1.1 B −1.9 0.0 −2.1 −0.6 1.8 0.6 1.2 −0.3

22.5° A −1.5 −1.6 −1.5 −1.7 1.7 1.8 0.5 −1.0 B −2.4 −0.3 −2.3 −0.9 2.2 0.7 1.3 0.0

30° A −1.8 −1.8 −1.5 −1.8 2.1 2.1 0.6 −1.0 B −2.5 −0.5 −2.3 −1.1 2.6 1.0 1.6 0.1

37.5° A −1.8 −1.8 −1.5 −1.8 2.1 2.2 0.7 −0.9 B −2.4 −0.6 −2.2 −1.1 2.7 1.1 1.9 0.3

45° A −1.6 −1.8 −1.3 −1.8 2.2 2.5 0.8 −0.9 B −2.3 −0.7 −1.9 −1.2 2.6 1.4 2.1 0.4

Notes

1. CNW and CNL denote net pressures (contributions from top and bottom surfaces) for windward and leeward half of roof surfaces, respectively.

2. Clear wind flow denotes relatively unobstructed wind flow with blockage less than or equal to 50%. Obstructed wind flow denotes objects below roof inhibiting wind flow (>50% blockage).

3. For values of θ between 7.5° and 45°, linear interpolation is permitted. For values of θ less than 7.5°, use load coefficients for 0°. 4. Plus and minus signs signify pressures acting toward and away from the top roof surface, respectively. 5. All load cases shown for each roof angle shall be investigated.

FIGURE 27.3-4 Main Wind Force Resisting System, Part 1 (0.25 ≤ h∕L ≤ 1.0): Net Pressure Coefficient, CN, for Open Buildings with Monoslope Free Roofs, θ≤45°, γ= 0°, 180°)

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 279

Diagram

Notation L = Horizontal dimension of roof, measured in the along-wind direction, ft (m). h =Mean roof height, ft (m). γ = Direction of wind, degrees. θ = Angle of plane of roof from horizontal, degrees.

Net Pressure Coefficient, CN

Roof Angle, θ Load Case

Wind Direction, γ =0°, 180°

Clear Wind Flow Obstructed Wind Flow

CNW CNL CNW CNL

7.5° A 1.1 −0.3 −1.6 −1.0 B 0.2 −1.2 −0.9 −1.7

15° A 1.1 −0.4 −1.2 −1.0 B 0.1 −1.1 −0.6 −1.6

22.5° A 1.1 0.1 −1.2 −1.2 B −0.1 −0.8 −0.8 −1.7

30° A 1.3 0.3 −0.7 −0.7 B −0.1 −0.9 −0.2 −1.1

37.5° A 1.3 0.6 −0.6 −0.6 B −0.2 −0.6 −0.3 −0.9

45° A 1.1 0.9 −0.5 −0.5 B −0.3 −0.5 −0.3 −0.7

Notes

1. CNW and CNL denote net pressures (contributions from top and bottom surfaces) for windward and leeward half of roof surfaces, respectively.

2. Clear wind flow denotes relatively unobstructed wind flow with blockage less than or equal to 50%. Obstructed wind flow denotes objects below roof inhibiting wind flow (>50% blockage).

3. For values of θ between 7.5° and 45°, linear interpolation is permitted. For values of θ less than 7.5°, use monoslope roof load coefficients.

4. Plus and minus signs signify pressures acting toward and away from the top roof surface, respectively. 5. All load cases shown for each roof angle shall be investigated.

FIGURE 27.3-5 Main Wind Force Resisting System, Part 1 (0.25 ≤ h∕L ≤ 1.0): Net Pressure Coefficient, CN , for Open Buildings with Pitched Free Roofs, θ≤45°, γ= 0°, 180°

280 STANDARD ASCE/SEI 7-16

Diagram

Notation L = Horizontal dimension of roof, measured in the along-wind direction, ft (m). h =Mean roof height, ft (m). γ = Direction of wind, degrees. θ = Angle of plane of roof from horizontal, degrees.

Net Pressure Coefficient, CN

Roof Angle, θ Load Case

Wind Direction, γ= 0°, 180°

Clear Wind Flow Obstructed Wind Flow

CNW CNL CNW CNL

7.5° A −1.1 0.3 −1.6 −0.5 B −0.2 1.2 −0.9 −0.8

15° A −1.1 0.4 −1.2 −0.5 B 0.1 1.1 −0.6 −0.8

22.5° A −1.1 −0.1 −1.2 −0.6 B −0.1 0.8 −0.8 −0.8

30° A −1.3 −0.3 −1.4 −0.4 B −0.1 0.9 −0.2 −0.5

37.5° A −1.3 −0.6 −1.4 −0.3 B 0.2 0.6 −0.3 −0.4

45° A −1.1 −0.9 −1.2 −0.3 B 0.3 0.5 −0.3 −0.4

Notes

1. CNW and CNL denote net pressures (contributions from top and bottom surfaces) for windward and leeward half of roof surfaces, respectively.

2. Clear wind flow denotes relatively unobstructed wind flow with blockage less than or equal to 50%. Obstructed wind flow denotes objects below roof inhibiting wind flow (>50% blockage).

3. For values of θ between 7.5° and 45°, linear interpolation is permitted. For values of θ less than 7.5°, use monoslope roof load coefficients.

4. Plus and minus signs signify pressures acting toward and away from the top roof surface, respectively. 5. All load cases shown for each roof angle shall be investigated.

FIGURE 27.3-6 Main Wind Force Resisting System, Part 1 (0.25 ≤ h∕L ≤ 1.0): Net Pressure Coefficient, CN , for Open Buildings with Troughed Free Roofs, θ≤45°, γ= 0°, 180°

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 281

Diagrams

Notation L = Horizontal dimension of roof, measured in the along-wind direction, ft (m). h =Mean roof height, ft (m). See Figs. 27.3-4, 27.3-5, or 27.3-6 for a graphical depiction of this dimension. γ = Direction of wind, degrees. θ = Angle of plane of roof from horizontal, degrees.

Net Pressure Coefficient, CN

Horizontal Distance from Windward Edge Roof Angle θ Load Case

Clear Wind Flow Obstructed Wind Flow CN CN

<h All shapes A −0.8 −1.2 θ < 45° B 0.8 0.5

>h; <2 h All shapes A −0.6 −0.9 θ < 45° B 0.5 0.5

>2h All shapes A −0.3 −0.6 θ < 45° B 0.3 0.3

Notes

1. CN denotes net pressures (contributions from top and bottom surfaces). 2. Clear wind flow denotes relatively unobstructed wind flow with blockage less than or equal to 50%. Obstructed wind flow denotes

objects below roof inhibiting wind flow (>50% blockage). 3. Plus and minus signs signify pressures acting toward and away from the top roof surface, respectively. 4. All load cases shown for each roof angle shall be investigated. 5. For monoslope roofs with θ less than 5 degrees, CN values shown apply also for cases where γ= 0 degrees and 0.05 less than or

equal to h∕ L less than or equal to 0.25. See Fig. 27.3-4 for other h∕ L values.

FIGURE 27.3-7 Main Wind Force Resisting System, Part 1 (0.25 ≤ h∕L ≤ 1.0): Net Pressure Coefficient, CN , for Open Buildings with Free Roofs, θ≤45°, γ= 90°, 270°

282 STANDARD ASCE/SEI 7-16

Diagrams

Notation PWX , PWY =Windward face design pressure acting in the x, y principal axis, respectively. PLX , PLY = Leeward face design pressure acting in the x, y principal axis, respectively. eðeX ; eYÞ = Eccentricity for the x, y principal axis of the structure, respectively.

MT = Torsional moment per unit height acting about a vertical axis of the building.

Case 1. Full design wind pressure acting on the projected area perpendicular to each principal axis of the structure, considered separately along each principal axis.

Case 2. Three-quarters of the design wind pressure acting on the projected area perpendicular to each principal axis of the structure in conjunction with a torsional moment as shown, considered separately for each principal axis.

Case 3. Wind loading as defined in Case 1, but considered to act simultaneously at 75% of the specified value. Case 4. Wind loading as defined in Case 2, but considered to act simultaneously at 75% of the specified value.

Notes

1. Design wind pressures for windward and leeward faces shall be determined in accordance with the provisions of Sections 27.3.1 and 27.3.2 as applicable for buildings of all heights.

2. Diagrams show plan views of buildings.

FIGURE 27.3-8 Main Wind Force Resisting System, Part 1 (All Heights): Design Wind Load Cases

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 283

PART 2: ENCLOSED SIMPLE DIAPHRAGM BUILDINGS WITH h ≤ 160 ft (h ≤ 48.8 m)

User Note: Part 2 of Chapter 27 is a simplified method for determining the wind pressures for the MWFRS of enclosed, simple diaphragm buildings the height h of which is ≤160 ft (48.8 m). The wind pressures are obtained directly from a table. The building may be of any general plan shape and roof geometry that matches the specified figures. This method is a simplification of the traditional “all heights” method (Directional Procedure) contained in Part 1 of Chapter 27.

27.4 GENERAL REQUIREMENTS

27.4.1 Design Procedure. The procedure specified herein applies to the determination of MWFRS wind loads of enclosed simple diaphragm buildings, as defined in Section 26.2, with a mean roof height h ≤ 160 ft (h ≤ 48.8 m). The steps required for the determination of MWFRS wind loads on enclosed simple diaphragm buildings are shown in Table 27.4-1.

27.4.2 Conditions. In addition to the requirements in Section 27.1.2, a building that has design wind loads determined in accordance with this section shall meet all of the follow- ing conditions for either a Class 1 or Class 2 building (Fig. 27.4-1):

Class 1 Buildings:

1. The building shall be an enclosed simple diaphragm build- ing as defined in Section 26.2.

2. The building shall have a mean roof height h ≤ 60 ft (h ≤ 18.3 m).

3. The ratio of L ∕B shall not be less than 0.2 nor more than 5.0 (0.2 ≤ L ∕B ≤ 5.0).

Class 2 Buildings:

1. The building shall be an enclosed simple diaphragm build- ing as defined in Section 26.2.

2. The building shall have a mean roof height 60 ft < h ≤ 160 ft (18.3 m < h ≤ 48.8 m).

3. The ratio of L ∕B shall not be less than 0.5 nor more than 2.0 (0.5 ≤ L ∕B ≤ 2.0).

4. The fundamental natural frequency (hertz) of the building shall not be less 75∕ h where h is in feet.

27.4.3 Wind Load Parameters Specified in Chapter 26. Refer to Chapter 26 for determination of basic wind speed, V (Section 26.5), exposure category (Section 26.7), and topographic factor Kzt (Section 26.10).

27.4.4 Topographic Effects. The wind pressures determined from this section shall be multiplied by Kzt as determined from Section 26.10 using one value of Kzt for the building calculated at 0.33h. Alternatively, it shall be permitted to enter Tables 27.5-1 and 27.5-2 with a wind velocity equal to V

ffiffiffiffiffiffiffi Kzt

p where Kzt is

determined at a height of 0.33h.

27.4.5 Diaphragm Flexibility. The design procedure specified herein applies to buildings that have either rigid or flexible diaphragms. The structural analysis shall consider the

relative stiffness of diaphragms and the vertical elements of the MWFRS.

Diaphragms constructed of wood panels can be idealized as flexible. Diaphragms constructed of untopped metal decks, concrete-filled metal decks, and concrete slabs, each having a span-to-depth ratio of 2 or less, are permitted to be idealized as rigid for consideration of wind loading.

27.5 WIND LOADS: MAIN WIND FORCE RESISTING SYSTEM

27.5.1 Wall and Roof Surfaces: Class 1 and 2 Buildings. Net wind pressures for the walls and roof surfaces shall be determined from Tables 27.5-1 and 27.5-2, respectively, for the applicable exposure category as determined by Section 26.7.

For Class 1 buildings with L ∕B values less than 0.5, use wind pressures tabulated for L ∕B= 0.5. For Class 1 buildings with L ∕B values greater than 2.0, use wind pressures tabulated for L ∕B= 2.0.

Net wall pressures shall be applied to the projected area of the building walls in the direction of the wind, and exterior sidewall pressures shall be applied to the projected area of the building walls normal to the direction of the wind acting outward according to Note 3 of Table 27.5-1, simultaneously with the roof pressures from Table 27.5-2, as shown in Fig. 27.5-1.

Where two load cases are shown in the table of roof pressures, the effects of each load case shall be investigated separately. The MWFRS in each direction shall be designed for the wind load cases as defined in Fig. 27.3-8.

EXCEPTION: The torsional load cases in Fig. 27.3-8 (Case 2 and Case 4) need not be considered for buildings that meet the requirements of Appendix D.

27.5.2 Parapets. The effect of horizontal wind loads applied to all vertical surfaces of roof parapets for the design of the MWFRS shall be based on the application of an additional net horizontal wind pressure applied to the projected area of the parapet surface equal to 2.25 times the wall pressures tabulated in Table 27.5-1 for L ∕B= 1.0. The net pressure specified accounts for both the windward and leeward parapet loading on both the windward and leeward building surface. The parapet pressure shall be applied simultaneously with the specified wall and roof pressures shown in the table in

Table 27.4-1 Steps to Determine MWFRS Wind Loads for Enclosed, Simple Diaphragm Buildings, h ≤ 160 ft (h ≤ 48.8 m)

Step 1: Determine Risk Category of building; see Table 1.5-1. Step 2: Determine the basic wind speed, V , for applicable Risk Category; see

Figs. 26.5-1 and 26.5-2. Step 3: Determine wind load parameters:

• Exposure category B, C, or D; see Section 26.7. • Topographic factor, Kzt ; see Section 26.8 and Fig. 26.8-1. • Enclosure classification; see Section 26.12.

Step 4: Enter table to determine net pressures on walls at top and base of building respectively, ph; p0, Table 27.5-1.

Step 5: Enter table to determine net roof pressures, pz, Table 27.5-2. Step 6: Determine topographic factor, Kzt , and apply factor to wall and roof

pressures (if applicable); see Section 26.8. Step 7: Apply loads to walls and roofs simultaneously.

284 STANDARD ASCE/SEI 7-16

Fig. 27.5-2. The height h used in Table 27.5-1 to determine the parapet pressure shall be the height to the top of the parapet as shown in Fig. 27.5-2 (use h= hp).

27.5.3 Roof Overhangs. The effect of vertical wind loads on any roof overhangs shall be based on the application of a positive wind pressure on the underside of the windward overhang equal to 75% of the roof edge pressure from Table 27.5-2 for Zone 1 or Zone 3, as applicable. This pressure shall be applied to the windward roof overhang only and shall be applied

simultaneously with other tabulated wall and roof pressures, as shown in Fig. 27.5-3.

27.6 CONSENSUS STANDARDS AND OTHER REFERENCED DOCUMENTS

No consensus standards and other documents that shall be considered part of this standard are referenced in this chapter.

Diagrams

0.2L ≤ B ≤ 5L

L

h ≤ 60 ft (h ≤ 18.3 m)

Plan

Elevation

Class 1 Building

Plan

0.5L ≤ B ≤ 2L

L

h = 60–160 ft (h ≤ 18.3–48.8 m)

Class 2 Building Elevation

Mean roof

Mean roof

Notation B = Horizontal dimension of building, in ft (m), measured normal to wind direction. L = Horizontal dimension of building, in ft (m), measured parallel to wind direction. h =Mean roof height, in ft (m), except that eave height shall be used for θ ≤ 10 degrees.

Note Roof form may be flat, gable, mansard, or hip.

FIGURE 27.4-1 Main Wind Force Resisting System, Part 2 [h ≤ 160 ft (h ≤ 48.8 m)]: Building Class for Enclosed Simple Diaphragm Buildings (Building Geometry Requirements)

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 285

Diagram

FIGURE 27.5-1 Main Wind Force Resisting System, Part 2 [h ≤ 160 ft (h ≤ 48.8 m)]: Enclosed Simple Diaphragm Buildings, Wind Pressures, Walls and Roof

Note For Application of Wind Pressures, see Tables 27.5-1 and 27.5-2

Diagram

FIGURE 27.5-2 Main Wind Force Resisting System, Part 2 [h ≤ 160 ft (h ≤ 48.8 m)]: Enclosed Simple Diaphragm Buildings, Parapet Wind Loads.

Note For Application of Parapet Wind Loads, see Table 27.5-1

286 STANDARD ASCE/SEI 7-16

Table 27.5-1 Main Wind Force Resisting System, Part 2 [h ≤ 160 ft (h ≤ 48.8 m)]: Enclosed Simple Diaphragm Buildings—Wind Pressures—Walls

Parameters for Application of Wall Pressures

Notation L = Building plan dimension parallel to wind direction, ft (m). B = Building plan dimension perpendicular to wind direction, ft (m). h = Mean roof height, ft (m). ph, p0 = Along-wind net wall pressure at top and base of building, respectively, psf (kN/m

2).

Notes for Wall Pressure Tables 1. From table for each Exposure (B, C or D), V, L/B, and h, determine ph (top number) and p0 (bottom number)

horizontal along-wind net wall pressures. 2. Sidewall external pressures shall be uniform over the wall surface acting outward and shall be taken as 54% of

the tabulated ph pressure for 0.2 L/B 1.0 and 64% of the tabulated ph pressure for 2.0 ≤ L/B ≤ 5.0. Linear interpolation shall apply for 1.0 < L/B < 2.0. Sidewall external pressures do not include effect of internal pressure.

3. Apply along-wind net wall pressures as shown above to the projected area of the building walls in the direction of the wind and apply external sidewall pressures to the projected area of the building walls normal to the direction wind, simultaneously with the roof pressures from Table 27.5-2.

4. Distribution of tabulated net wall pressures between windward and leeward wall faces shall be based on the linear distribution of total net pressure with building height as shown above and the leeward external wall pressures assumed uniformly distributed over the leeward wall surface acting outward at 38% of ph for

L/B ≤0.2 ≤ 1.0 and 27% of ph for 2.0 L/B 5.0. Linear interpolation shall be used for 1.0 < L/B < 2.0. The remaining net pressure shall be applied to the windward walls as an external wall pressure acting toward the wall surface. Windward and leeward wall pressures so determined do not include effect of internal pressure.

5. Interpolation between values of V, h, and L/B is permitted. 6. 1.0 ft = 0.3048 m; 1.0 lb/ft2 = 0.0479 kN/m .2

Plan Wind Pressure Elevation

h

L

B Wind h

ph

p0

continues

Diagram

FIGURE 27.5-3 Main Wind Force Resisting System, Part 2: Enclosed Simple Diaphragm Buildings, Roof Overhang Wind Loads

Note For Application of Roof Overhang Wind Loads, see Table 27.5-1

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 287

T ab

le 27

.5 -1

(C o n ti n u ed

). M ai n W in d F o rc e R es

is ti n g S ys

te m , P ar t 2 [h

≤ 16

0 ft (h

≤ 48

.8 m )] : E n cl o se

d S im

p le

D ia p h ra g m

B u ild

in g s—

W in d P re ss

u re s—

W al ls

E xp

os ur

e B

h (f t)

A lo

n g

- w

in d

N et

W

al l

P re

ss u

re

V (m

i/h )

11 0

11 5

12 0

13 0

14 0

16 0

18 0

20 0

L /B

L

/B

L /B

L

/B

L /B

L

/B

L /B

L

/B

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

16 0

p h 38

.1

37 .7

34

.1

42 .1

41

.7

37 .8

46

.4

45 .9

41

.7

55 .8

55

.1

50 .2

66

.3

65 .4

59

.7

91 .0

89

.4

81 .8

12

0. 8

11 8.

3 10

8. 5

15 6.

2 15

2. 4

14 0.

0

p 0 25

.6

25 .4

21

.0

28 .3

28

.1

23 .3

31

.2

30 .9

25

.7

37 .5

37

.1

30 .9

44

.6

44 .0

36

.8

61 .2

60

.1

50 .4

81

.3

79 .6

66

.9

10 5.

2 10

2. 6

86 .2

15 0

p h 36

.9

36 .6

33

.0

40 .7

40

.4

36 .5

44

.9

44 .4

40 .3

53 .9

53 .3

48 .5

63 .9

63 .1

57 .6

87 .5

86 .1

78 .9

11

6. 1

11 3.

8 10

4. 5

14 9.

9 14

6. 5

13 4.

7

p 0 25

.1

24 .9

20

.6

27 .7

27

.5

22 .8

30

.5

30 .2

25

.2

36 .7

36

.2

30 .3

43

.5

43 .0

36

.0

59 .6

58

.6

49 .3

79

.0

77 .4

65

.3

10 2.

0 99

.7

84 .2

14 0

p h 36

.6

35 .4

31

.9

39 .3

39

.1

35 .3

43

.3

42 .9

38

.9

51 .9

51

.4

46 .7

61

.5

60 .8

55

.5

84 .0

82

.8

75 .9

11

1. 2

10 9.

2 10

0. 4

14 3.

5 14

0. 5

12 9.

3

p 0 24

.5

24 .4

20

.2

27 .1

26

.9

22 .4

29

.8

29 .6

24

.6

35 .7

35

.4

29 .6

42

.4

41 .9

35

.2

57 .9

57

.0

48 .1

76

.6

75 .2

63

.7

98 .8

96

.7

82 .0

13 0

p h 34

.4

34 .2

30

.8

37 .9

37

.7

34 .0

41

.7

41 .4

37

.4

49 .9

49

.5

44 .9

59

.1

58 .5

53

.3

80 .5

79

.5

72 .8

10

6. 3

10 4.

6 96

.2

13 6.

9 13

4. 3

12 3.

8

p 0 24

.0

23 .9

19

.8

26 .5

26

.3

21 .9

29

.1

28 .9

24

.1

34 .8

34

.5

28 .9

41

.2

40 .8

34

.3

56 .2

55

.4

46 .9

74

.2

73 .0

62

.0

95 .5

93

.7

79 .8

12 0

p h 33

.1

33 .0

29

.6

36 .5

36

.3

32 .7

40

.1

39 .9

35

.9

47 .9

47

.6

43 .1

56

.6

56 .2

51

.0

76 .9

76

.1

69 .6

10

1. 3

99 .9

91

.8

13 0.

2 12

8. 0

11 8.

0

p 0 23

.4

23 .3

19

.4

25 .8

25

.7

21 .4

28

.4

28 .2

23 .6

33 .9

33 .7

28 .3

40 .1

39 .7

33 .5

54 .4

53 .8

45 .6

71

.7

70 .7

60

.2

92 .2

90

.6

77 .4

11 0

p h 31

.8

31 .7

28

.4

35 .1

34

.9

31 .3

38

.5

38 .3

34

.4

45 .9

45

.6

41 .2

54

.1

53 .8

48

.8

73 .3

72

.6

66 .3

96

.3

95 .1

87

.4

12 3.

5 12

1. 6

11 2.

1

p 0 22

.9

22 .8

19

.0

25 .2

25

.1

20 .9

27

.7

27 .5

23

.0

33 .0

32

.8

27 .6

38

.9

38 .7

32

.6

52 .7

52

.2

44 .4

69

.2

68 .4

58

.4

88 .8

87

.4

75 .0

10 0

p h 30

.5

30 .4

27

.1

33 .6

33

.5

29 .9

36

.8

36 .7

32

.9

43 .8

43

.6

39 .3

51

.6

51 .3

46

.4

69 .6

69

.1

62 .9

91

.2

90 .3

82

.8

11 6.

6 11

5. 1

10 6.

0

p 0 22

.3

22 .3

18

.5

24 .6

24

.5

20 .4

26

.9

26 .8

22

.5

32 .1

31

.9

26 .8

37

.8

37 .6

31

.7

50 .9

50

.5

43 .0

66

.7

66 .0

56

.6

85 .3

84

.2

72 .5

90

p h 29

.2

29 .1

25

.9

32 .1

32

.0

28 .5

35

.1

35 .0

31

.2

44 .7

41

.6

37 .3

49

.1

48 .8

44

.0

65 .9

65

.5

59 .5

86

.0

85 .3

78

.0

10 9.

6 10

8. 5

99 .8

p 0 21

.8

21 .7

18

.1

23 .9

23

.9

19 .9

26

.2

26 .1

21

.9

31 .1

31

.0

26 .1

36

.6

36 .4

30

.8

49 .2

48

.9

41 .7

64

.2

63 .6

54

.6

81 .8

80

.9

69 .9

80

p h 27

.8

27 .7

24

.5

30 .5

30

.5

27 .0

33

.4

33 .3

29

.6

39 .6

39

.5

35 .2

46

.4

46 .3

41

.5

62 .2

61

.9

55 .9

80

.8

80 .3

73

.1

10 2.

6 10

1. 7

93 .3

p 0 21

.2

21 .2

17

.7

23 .3

23

.2

19 .4

25

.5

25 .4

21

.3

30 .2

30

.1

25 .4

35

.4

35 .3

29

.9

47 .4

47

.2

40 .3

61

.6

61 .2

52

.6

78 .3

77

.6

67 .2

70

p h 26

.3

26 .3

23

.1

28 .9

28

.8

25 .4

31

.6

31 .5

27

.9

37 .4

37

.3

33 .1

43

.7

43 .6

38

.9

58 .3

58

.1

52 .2

75

.5

75 .1

68

.1

95 .5

94

.9

86 .6

p 0 20

.6

20 .6

17

.2

22 .6

22

.6

18 .9

24

.7

24 .7

20

.7

29 .3

29

.2

24 .6

34

.2

34 .2

28

.9

45 .6

45

.5

38 .8

59

.1

58 .8

50

.6

74 .7

74

.3

64 .3

60

p h 24

.8

24 .8

21

.7

27 .2

27

.1

23 .8

29

.7

29 .6

26

.1

35 .1

35

.0

30 .9

41

.0

40 .9

36

.2

54 .4

54

.2

48 .4

70

.1

69 .8

62

.8

88 .2

87

.9

79 .6

p 0 20

.0

20 .0

16

.7

21 .9

21

.9

18 .4

23

.9

23 .9

20

.1

28 .3

28

.2

23 .6

33

.0

33 .0

27

.9

43 .9

43

.8

37 .3

56

.5

56 .3

48

.5

71 .2

70

.9

61 .4

50

p h 23

.1

23 .1

20

.2

25 .3

25

.3

22 .1

27

.6

27 .6

24

.2

32 .6

32

.6

28 .6

38

.0

38 .0

33

.4

50 .3

50

.2

44 .5

64

.5

64 .4

57

.4

80 .9

80

.7

72 .5

p 0 19

.3

19 .3

16

.3

21 .2

21

.2

17 .8

23

.1

23 .1

19

.5

27 .3

27

.3

23 .0

31

.8

31 .8

26

.9

42 .0

42

.0

35 .8

54

.0

53 .8

46

.3

67 .6

67

.5

58 .4

40

p h 21

.5

21 .5

18

.6

23 .5

23

.5

20 .4

25

.6

25 .6

22

.3

30 .2

30

.2

26 .3

35

.1

35 .1

30

.7

46 .3

46

.2

40 .7

59

.2

59 .1

52

.3

73 .9

73

.8

65 .7

p 0 18

.8

18 .7

15

.8

20 .5

20

.5

17 .4

22

.4

22 .4

18

.9

26 .4

26

.4

22 .4

30

.7

30 .7

26

.1

40 .5

40

.4

34 .6

51

.7

51 .7

44

.5

64 .6

64

.5

55 .8

30

p h 19

.6

19 .6

16

.9

21 .4

21

.4

18 .5

23

.3

23 .3

20

.2

27 .5

27

.4

23 .8

31

.9

31 .9

27

.7

44 .9

41

.9

36 .6

53

.4

53 .4

46

.8

66 .5

66

.4

58 .5

p 0 18

.1

18 .1

15

.4

19 .8

19

.8

16 .8

21

.5

21 .5

18

.4

25 .3

25

.3

21 .6

29

.5

29 .5

25

.2

38 .7

38

.7

33 .2

49

.3

49 .3

42

.5

61 .4

61

.3

53 .1

20

p h 17

.5

17 .5

15

.1

19 .2

19

.2

16 .6

20

.9

20 .9

18

.1

24 .5

24

.5

21 .2

28

.5

28 .5

24

.7

37 .3

37

.3

32 .4

47

.4

47 .4

41

.3

58 .8

58

.8

51 .4

p 0 17

.2

17 .2

14

.8

18 .8

18

.8

16 .2

20

.5

20 .5

17

.7

24 .1

24

.1

20 .8

28

.0

28 .0

24

.2

36 .7

36

.7

31 .7

46

.6

46 .6

40

.4

57 .8

57

.7

50 .3

15

p h 16

.7

16 .7

14

.5

18 .2

18

.2

15 .8

19

.9

19 .9

17

.3

23 .3

23

.3

20 .3

27

.1

27 .1

23

.6

35 .4

35

.4

30 .9

44

.9

44 .9

39

.3

55 .6

55

.6

48 .7

p 0 16

.7

16 .7

14

.5

18 .2

18

.2

15 .8

19

.9

19 .9

17

.3

23 .3

23

.3

20 .3

27

.1

27 .1

23

.6

35 .4

35

.4

30 .9

44

.9

44 .9

39

.3

55 .6

55

.6

48 .7

co nt in ue

s

288 STANDARD ASCE/SEI 7-16

T ab

le 27

.5 -1

(C o n ti n u ed

). M ai n W in d F o rc e R es

is ti n g S ys

te m , P ar t 2 [h

≤ 16

0 ft (h

≤ 48

.8 m )] : E n cl o se

d S im

p le

D ia p h ra g m

B u ild

in g s—

W in d P re ss

u re s—

W al ls

E xp

os ur

e C

h (f t)

V (m

i/h )

11 0

11 5

12 0

13 0

14 0

16 0

18 0

20 0

L /B

L

/B

L /B

L

/B

L /B

L

/B

L /B

L

/B

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

16 0

p h 49

.2

48 .7

43

.7

54 .5

53

.8

48 .3

60

.0

59 .3

53

.3

72 .2

71

.1

64 .1

85

.8

84 .3

76

.1

11 7.

4 11

5. 0

10 3.

9 15

5. 4

15 1.

8 13

7. 2

20 0.

2 19

5. 0

17 6.

2

p 0 36

.1

35 .7

30

.0

40 .0

39

.5

33 .2

44

.1

43 .5

36

.6

53 .0

52

.2

44 .0

62

.9

61 .9

52

.3

86 .2

84

.4

71 .5

11

4. 1

11 1.

4 94

.3

14 6.

9 14

3. 1

12 1.

1

15 0

p h 48

.0

47 .5

42

.6

53 .0

52

.4

47 .1

58

.4

57 .7

51 .9

70 .1

69 .2

62 .3

83 .3

82 .0

74 .0

11 3.

8 11

1. 7

10 1.

0 15

0. 6

14 7.

3 13

3. 3

19 8.

8 18

9. 0

17 1.

0

p 0 35

.5

35 .2

29

.6

39 .3

38

.8

32 .7

43

.3

42 .8

36

.1

52 .0

51

.3

43 .3

61

.7

60 .7

51

.4

84 .3

82

.8

70 .2

11

1. 5

10 9.

1 92

.7

14 3.

5 14

0. 0

11 8.

9

14 0

p h 46

.6

46 .2

41

.4

51 .5

51

.0

45 .8

56

.7

56 .1

50

.4

68 .1

67

.2

60 .6

80

.7

79 .6

71

.8

11 0.

2 10

8. 3

98 .0

14

5. 6

14 2.

6 12

9. 2

18 7.

2 18

2. 9

16 5.

7

p 0 34

.9

34 .6

29

.1

38 .6

38

.2

32 .2

42

.4

42 .0

35

.5

50 .9

50

.3

42 .6

60

.4

59 .5

50

.6

82 .4

81

.0

68 .9

10

8. 9

10 6.

7 90

.9

14 0.

0 13

6. 8

11 6.

6

13 0

p h 45

.3

45 .0

40

.2

50 .0

49

.6

44 .5

55

.0

54 .5

48

.9

65 .9

65

.2

58 .7

78

.1

77 .1

69

.6

10 6.

4 10

4. 7

94 .8

14

0. 4

13 7.

7 12

4. 9

18 0.

4 17

6. 5

16 0.

1

p 0 34

.3

34 .0

28

.7

37 .8

37

.5

31 .7

41

.6

41 .2

34

.9

49 .9

49

.3

41 .9

59

.1

58 .3

49

.6

80 .5

79

.2

67 .6

10

6. 2

10 4.

1 89

.1

13 6.

4 13

3. 4

11 4.

2

12 0

p h 43

.9

43 .6

39

.0

48 .5

48

.1

43 .1

53

.3

52 .8

47

.4

63 .8

63

.1

56 .8

75

.4

74 .6

67

.3

10 2.

6 10

1. 1

91 .5

13

5. 1

13 2.

7 12

0. 5

17 3.

3 16

9. 8

15 4.

3

p 0 33

.6

33 .4

28

.2

37 .1

36

.8

31 .1

40

.7

40 .4

34 .3

48 .8

48 .3

41 .1

57 .7

57 .1

48 .7

78 .5

77 .3

66 .2

10

3. 3

10 1.

5 87

.1 13

2. 6

12 9.

9 11

1. 6

11 0

p h 42

.5

42 .3

37

.7

46 .9

46

.6

41 .6

51

.5

51 .1

45

.8

61 .5

61

.0

54 .8

72

.7

72 .0

64

.8

98 .6

97

.3

88 .1

12

9. 6

12 7.

6 11

5. 8

16 6.

0 16

3. 0

14 8.

2

p 0 32

.9

32 .8

27

.7

36 .3

36

.1

30 .6

39

.9

39 .6

33

.6

47 .7

47

.3

40 .3

56

.3

55 .8

47

.6

76 .4

75

.4

64 .7

10

0. 4

98 .8

85

.1

12 8.

6 12

6. 3

10 8.

9

10 0

p h 41

.1

40 .9

36

.4

45 .2

45

.0

40 .1

49

.6

49 .3

44

.1

59 .2

58

.8

52 .7

69

.8

69 .3

62

.3

94 .5

93

.5

84 .5

12

3. 9

12 2.

2 11

1. 0

15 8.

5 15

5. 9

14 1.

9

p 0 32

.3

32 .1

27

.2

35 .5

35

.4

30 .0

39

.0

38 .8

33

.0

46 .5

46

.2

39 .4

54

.9

54 .4

46

.6

74 .2

73

.4

63 .2

97

.4

96 .0

82

.9

12 4.

5 12

2. 5

10 6.

1

90

p h 39

.6

39 .4

35

.0

43 .5

43

.3

38 .5

47

.7

47 .5

42

.3

56 .8

56

.5

50 .6

66

.9

66 .5

59

.7

90 .3

89

.4

80 .8

11

8. 1

11 6.

7 10

5. 9

15 0.

6 14

8. 5

13 5.

2

p 0 31

.6

31 .5

26

.6

34 .7

34

.6

29 .4

38

.1

37 .9

32

.3

45 .4

45

.1

38 .5

53

.4

53 .1

45

.5

72 .1

71

.4

61 .6

94

.2

93 .2

80

.7

12 0.

3 11

8. 6

10 3.

0

80

p h 38

.0

37 .9

33

.5

41 .8

41

.6

36 .9

45

.8

45 .6

40

.5

54 .4

54

.2

48 .3

63

.9

63 .6

56

.9

85 .9

85

.3

76 .8

11

2. 0

11 1.

0 10

0. 5

14 2.

6 14

0. 9

12 8.

1

p 0 30

.9

30 .8

26

.1

33 .9

33

.8

28 .7

37

.2

37 .1

31

.5

44 .2

44

.0

37 .6

52

.0

51 .7

44

.3

69 .8

69

.3

59 .8

91

.0

90 .2

78

.3

11 5.

8 11

4. 5

99 .8

70

p h 36

.4

36 .3

32

.0

39 .9

39

.9

35 .2

43

.7

43 .6

38

.6

51 .9

51

.7

45 .9

60

.8

60 .6

54

.0

81 .4

81

.0

72 .7

10

5. 8

10 5.

0 94

.9

13 4.

2 13

3. 0

12 0.

7

p 0 30

.2

30 .1

25

.5

33 .1

33

.1

28 .1

36

.3

36 .2

30

.8

43 .0

42

.9

36 .6

50

.5

50 .3

43

.1

67 .5

67

.2

58 .0

87

.8

87 .1

75

.7

11 1.

3 11

0. 3

96 .3

60

p h 34

.6

34 .6

30

.3

38 .0

38

.0

33 .3

41

.6

41 .5

36

.5

49 .2

49

.1

43 .4

57

.6

57 .4

50

.9

76 .8

76

.5

68 .3

99

.4

98 .8

88

.9

12 5.

6 12

4. 7

11 2.

8

p 0 29

.4

29 .4

24

.9

32 .3

32

.2

27 .4

35

.3

35 .2

30

.0

41 .8

41

.7

35 .6

48

.9

48 .8

41

.9

65 .2

65

.0

56 .1

84

.4

83 .9

73

.0

10 6.

7 10

5. 9

92 .7

50

p h 32

.8

32 .8

28

.6

36 .0

35

.9

31 .4

39

.3

39 .2

34

.3

46 .4

46

.3

40 .7

54

.2

54 .1

47

.7

72 .0

71

.8

63 .7

92

.7

92 .4

82

.5

11 6.

7 11

6. 1

10 4.

4

p 0 28

.7

28 .6

24

.3

31 .4

31

.4

26 .7

34

.3

34 .3

29

.2

40 .5

40

.5

34 .6

47

.4

47 .3

40

.5

62 .9

62

.7

54 .2

81

.0

80 .7

70

.2

10 1.

9 10

1. 4

88 .8

40

p h 30

.8

30 .8

26

.7

33 .7

33

.7

29 .3

36

.8

36 .8

32

.0

43 .4

43

.4

37 .8

50

.6

50 .5

44

.2

66 .9

66

.8

58 .8

85

.8

85 .6

75

.8

10 7.

4 10

7. 1

95 .5

p 0 27

.8

27 .8

23

.6

30 .5

30

.5

25 .9

33

.3

33 .2

28

.3

39 .2

39

.2

33 .5

45

.7

45 .7

39

.2

60 .4

60

.3

52 .1

77

.5

77 .3

67

.2

97 .1

96

.8

84 .6

30

p h 28

.5

28 .5

24

.6

31 .2

31

.2

27 .0

34

.1

34 .1

29

.5

40 .1

40

.1

34 .8

46

.7

46 .6

40

.5

61 .4

61

.4

53 .6

78

.4

78 .3

68

.8

97 .8

97

.6

86 .1

p 0 26

.9

26 .9

22

.9

29 .4

29

.4

25 .1

32

.1

32 .1

27

.4

37 .8

37

.8

32 .4

44

.0

43 .9

37

.7

57 .9

57

.8

49 .9

73

.9

73 .8

64

.0

92 .1

91

.9

80 .2

20

p h 26

.2

26 .2

22

.6

28 .6

28

.6

24 .7

31

.2

31 .2

26

.9

36 .7

36

.7

31 .7

42

.6

42 .6

36

.9

55 .9

55

.9

48 .5

71

.1

71 .1

61

.9

88 .2

88

.2

77 .0

p 0 25

.8

25 .8

22

.2

28 .3

28

.3

24 .3

30

.8

30 .8

26

.5

36 .2

36

.2

31 .2

42

.1

42 .1

36

.3

55 .2

55

.1

47 .7

70

.1

70 .1

60

.9

87 .1

87

.0

75 .8

15

p h 25

.2

25 .2

21

.8

27 .6

27

.6

23 .8

30

.0

30 .0

26

.0

35 .3

35

.3

30 .6

41

.0

41 .0

35

.5

53 .7

53

.7

46 .6

68

.1

68 .1

59

.3

84 .4

84

.4

73 .6

p 0 25

.2

25 .2

21

.8

27 .6

27

.6

23 .8

30

.0

30 .0

26

.0

35 .3

35

.3

30 .6

41

.0

41 .0

35

.5

53 .7

53

.7

46 .6

68

.1

68 .1

59

.3

84 .4

84

.4

73 .6

A lo

n g

- w

in d

N et

W

al l

P re

ss u

re

co nt in ue

s

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 289

T ab

le 27

.5 -1

(C o n ti n u ed

). M ai n W in d F o rc e R es

is ti n g S ys

te m , P ar t 2 [h

≤ 16

0 ft (h

≤ 48

.8 m )] : E n cl o se

d S im

p le

D ia p h ra g m

B u ild

in g s—

W in d P re ss

u re s—

W al ls

E xp

os ur

e D

V (m

i/h )

h (f

t)

11 0

11 5

12 0

13 0

14 0

16 0

18 0

20 0

L /B

L

/B

L /B

L

/B

L /B

L

/B

L /B

L

/B

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

0. 5

1 2

16 0

p h 55

.7

55 .1

49

.1

61 .6

60

.8

54 .3

67

.9

67 .0

59

.7

81 .5

80

.3

71 .7

96

.7

95 .0

85

.0

13 1.

9 12

9. 2

11 5.

6 17

3. 9

16 9.

9 15

2. 0

22 3.

0 21

7. 5

19 4.

4

p 0 42

.9

42 .4

35

.7

47 .4

46

.8

39 .5

52

.2

51 .5

43

.5

62 .7

61

.7

52 .2

74

.4

73 .1

61

.9

10 1.

4 99

.4

84 .2

13

3. 7

13 0.

7 11

0. 7

17 1.

5 16

7. 2

14 1.

6

15 0

p h 54

.5

53 .9

48

.0

60 .2

59

.5

53 .0

66

.3

65 .4

58

.4

79 .5

78

.4

70 .0

94

.3

92 .8

83

.0

12 8.

5 12

6. 0

11 2.

8 16

9. 3

16 5.

6 14

8. 3

21 7.

0 21

1. 8

18 9.

6

p 0 42

.2

41 .8

35

.3

46 .7

46

.1

39 .0

51

.4

50 .7

43

.0

61 .6

60

.8

51 .5

73

.1

71 .9

61

.0

99 .6

97

.7

83 .0

13

1. 2

12 8.

3 10

9. 1

16 8.

2 16

4. 2

13 9.

4

14 0

p h 53

.2

52 .7

46

.9

58 .7

58

.1

51 .8

64

.6

63 .9

57

.0

77 .5

76

.5

68 .3

91

.8

90 .4

80

.9

12 4.

9 12

2. 7

10 9.

9 16

4. 5

16 1.

1 14

4. 4

21 0.

7 20

5. 9

18 4.

5

p 0 41

.6

41 .2

34

.8

45 .9

45

.4

38 .5

50

.5

49 .9

42

.4

60 .6

59

.8

50 .8

71

.7

70 .7

60

.1

97 .7

95

.9

81 .7

12

8. 6

12 5.

9 10

7. 3

16 4.

7 16

0. 9

13 7.

2

13 0

p h 51

.8

51 .4

45

.7

57 .2

56

.7

50 .5

62

.9

62 .3

55

.5

75 .4

74

.5

66 .5

89

.2

88 .0

78

.7

12 1.

2 11

9. 2

10 6.

9 15

9. 5

15 6.

4 14

0. 3

20 4.

2 19

9. 7

17 9.

2

p 0 40

.9

40 .5

34

.4

45 .1

44

.7

38 .0

49

.7

49 .1

41

.8

59 .5

58

.8

50 .0

70

.4

69 .4

59

.2

95 .7

94

.1

80 .4

12

5. 8

12 3.

4 10

5. 5

16 1.

1 15

7. 6

13 4.

7

12 0

p h 50

.4

50 .1

44

.5

55 .7

55

.2

49 .1

61

.2

60 .6

54

.0

73 .2

72

.4

64 .7

86

.5

85 .5

76

.5

11 7.

4 11

5. 6

10 3.

7 15

4. 2

15 1.

5 13

6. 1

19 7.

3 19

3. 3

17 3.

7

p 0 40

.2

39 .9

33

.9

44 .4

44

.0

37 .4

48

.8

48 .3

41

.1

58 .3

57

.7

49 .2

69

.0

68 .1

58

.2

93 .6

92

.2

78 .9

12

2. 9

12 0.

7 10

3. 5

15 7.

3 15

4. 0

13 2.

2

11 0

p h 49

.0

48 .7

43

.2

54 .0

53

.6

47 .7

59

.4

58 .9

52

.4

70 .9

70

.2

62 .7

83

.8

82 .8

74

.1

11 3.

4 11

1. 9

10 0.

4 14

8. 8

14 6.

3 13

1. 6

19 0.

2 18

6. 5

16 7.

9

p 0 39

.5

39 .2

33

.3

43 .5

43

.2

36 .8

47

.8

47 .5

40

.4

57 .2

56

.6

48 .4

67

.5

66 .8

57

.2

91 .4

90

.2

77 .4

11

9. 9

11 7.

9 10

1. 5

15 3.

2 15

0. 3

12 9.

5

10 0

p h 47

.5

47 .3

41

.9

52 .4

52

.0

46 .2

57

.5

57 .1

50

.8

68 .6

68

.0

60 .7

80

.9

80 .1

71

.6

10 9.

3 10

8. 0

96 .9

14

3. 1

14 1.

0 12

6. 8

18 2.

7 17

9. 5

16 1.

7

p 0 38

.8

38 .6

32

.8

42 .7

42

.5

36 .2

46

.9

46 .6

39

.7

55 .9

55

.5

47 .5

66

.0

65 .4

56

.1

89 .2

88

.1

75 .9

11

6. 8

11 5.

0 99

.3

14 9.

0 14

6. 4

12 6.

6

90 p h

46 .0

45

.8

40 .5

50

.6

50 .4

44

.6

55 .5

55

.2

49 .0

66

.2

65 .7

58

.5

77 .9

77

.3

69 .0

10

5. 0

10 3.

9 93

.2

13 7.

2 13

5. 4

12 1.

8 17

4. 8

17 2.

1 15

5. 2

p 0 38

.0

37 .9

32

.2

41 .9

41

.7

35 .5

45

.9

45 .7

39

.0

54 .7

54

.3

46 .6

64

.4

63 .9

54

.9

86 .8

85

.9

74 .2

11

3. 5

11 2.

0 97

.0

14 4.

6 14

2. 3

12 3.

5

80 p h

44 .4

44

.2

39 .0

48

.8

48 .6

43

.0

53 .5

53

.3

47 .2

63

.6

63 .3

56

.2

74 .8

74

.3

66 .2

10

0. 6

99 .7

89

.3

13 1.

0 12

9. 6

11 6.

5 16

6. 6

16 4.

4 14

8. 2

p 0 37

.3

37 .1

31

.6

41 .0

40

.8

34 .8

44

.9

44 .7

38

.2

53 .4

53

.1

45 .6

62

.8

62 .4

53

.7

84 .4

83

.7

72 .4

11

0. 0

10 8.

8 94

.5

13 9.

9 13

8. 0

12 0.

2

70 p h

42 .7

42

.6

37 .4

46

.9

46 .8

41

.2

51 .4

51

.2

45 .2

61

.0

60 .7

53

.8

71 .6

71

.2

63 .3

95

.9

95 .2

85

.1

12 4.

6 12

3. 5

11 0.

9 15

8. 0

15 6.

3 14

0. 8

p 0 36

.5

36 .4

31

.0

40 .1

40

.0

34 .1

43

.9

43 .8

37

.4

52 .1

51

.9

44 .5

61

.2

60 .9

52

.4

81 .9

81

.4

70 .5

10

6. 5

10 5.

5 91

.8

13 5.

0 13

3. 5

11 6.

6

60 p h

40 .9

40

.9

35 .8

44

.9

44 .8

39

.3

49 .2

49

.0

43 .1

58

.2

58 .1

57

.2

68 .2

68

.0

60 .1

91

.0

90 .6

80

.6

11 7.

9 11

7. 1

10 4.

8 14

9. 0

14 7.

7 13

2. 8

p 0 35

.7

35 .6

30

.3

39 .2

39

.1

33 .4

42

.9

42 .8

36

.6

50 .8

50

.6

43 .4

59

.5

59 .3

51

.0

79 .4

79

.0

68 .4

10

2. 8

10 2.

1 88

.9

12 9.

9 12

8. 8

11 2.

7

50 p h

39 .0

39

.0

34 .0

42

.8

42 .7

37

.3

46 .8

46

.7

40 .8

55

.3

55 .2

48

.4

64 .7

64

.5

56 .8

85

.9

85 .6

75

.9

11 0.

8 11

0. 3

98 .3

13

9. 5

13 8.

7 12

4. 2

p 0 34

.9

34 .8

29

.7

38 .2

38

.2

32 .6

41

.8

41 .7

35

.7

49 .4

49

.3

42 .3

57

.7

57 .6

49

.6

76 .7

76

.5

66 .2

99

.0

98 .5

85

.8

12 4.

6 12

3. 8

10 8.

5

40 p h

37 .0

36

.9

32 .0

40

.5

40 .5

35

.1

44 .2

44

.2

38 .4

52

.2

52 .1

45

.4

60 .9

60

.8

53 .1

80

.5

80 .4

70

.7

10 3.

4 10

3. 1

91 .2

12

9. 6

12 9.

1 11

4. 9

p 0 34

.0

33 .9

28

.9

37 .2

37

.2

31 .7

40

.6

40 .6

34

.7

47 .9

47

.9

41 .1

55

.9

55 .8

48

.0

74 .0

73

.8

63 .9

95

.0

94 .7

82

.5

11 9.

1 11

8. 7

10 3.

9

30 p h

34 .7

34

.6

29 .9

37

.9

37 .9

32

.7

41 .4

41

.4

35 .7

48

.7

48 .7

42

.2

56 .7

56

.7

49 .2

74

.8

74 .7

65

.2

95 .5

95

.4

83 .7

11

9. 2

11 9.

0 10

4. 9

p 0 33

.0

33 .0

28

.2

36 .1

36

.1

30 .9

39

.4

39 .4

33

.7

46 .4

46

.3

39 .8

54

.0

54 .0

46

.4

71 .1

71

.1

61 .4

90

.9

90 .8

78

.9

11 3.

5 11

3. 2

98 .9

20 p h

32 .2

32

.1

27 .6

35

.2

35 .2

30

.3

38 .3

38

.3

33 .0

45

.1

45 .1

38

.8

52 .4

52

.4

45 .2

68

.7

68 .7

59

.5

87 .5

87

.4

76 .0

10

8. 6

10 8.

5 94

.7

p 0 31

.8

31 .8

27

.3

34 .8

34

.8

29 .9

37

.9

37 .9

32

.6

44 .6

44

.6

38 .3

51

.8

51 .8

44

.6

68 .0

68

.0

58 .8

86

.5

86 .5

75

.0

10 7.

5 10

7. 4

93 .5

15 p h

31 .1

31

.1

26 .8

34

.0

34 .0

29

.3

37 .0

37

.0

31 .9

43

.5

43 .5

37

.5

50 .5

50

.5

43 .6

66

.2

66 .1

57

.3

84 .0

84

.0

73 .0

10

4. 1

10 4.

1 90

.7

p 0 31

.1

31 .1

26

.8

34 .0

34

.0

29 .3

37

.0

37 .0

31

.9

43 .5

43

.5

37 .5

50

.5

50 .5

43

.6

66 .2

66

.1

57 .3

84

.0

84 .0

73

.0

10 4.

1 10

4. 1

90 .7

A lo

n g

- w

in d

N et

W

al l

P re

ss u

re

290 STANDARD ASCE/SEI 7-16

Table 27.5-2 Main Wind Force Resisting System, Part 2 [h ≤ 160 ft (h ≤ 48.8 m)]: Enclosed Simple Diaphragm Buildings—Wind Pressures—Roofs

Notes for Roof Pressure Tables

1. From table for Exposure C, V, h, and roof slope, determine roof pressure ph for each roof zone shown in the figures for

the applicable roof form. For other exposures B or D, multiply pressures from table by appropriate exposure

adjustment factor as determined from figure below.

2. Where two load cases are shown, both load cases shall be investigated. Load Case 2 is required to investigate maximum

overturning on the building from roof pressures shown.

3. Apply along-wind net wall pressures to the projected area of the building walls in the direction of the wind and apply

exterior sidewall pressures to the projected area of the building walls normal to the direction of the wind acting

outward, simultaneously with the roof pressures from this table.

4. Where a value of zero is shown in the tables for the flat roof case, it is provided for the purpose of interpolation.

5. Interpolation between V, h, and roof slope is permitted.

6. 1.0 ft = 0.3048 m; 1.0 lb/ft2 = 0.0479 kN/m .2

Exposure Adjustment Factor, Exposures B and D

Exposure Adjustment Factor h (ft.) Exp B Exp D 160 1.113 150 1.116 140 1.118 130 1.121 120 1.125 110 1.128 100 1.132 90 1.137 80 1.141 70 1.147 60 1.154 50 1.161 40 1.171 30 1.183 20 1.201 15

0.809 0.805 0.801 0.796 0.792 0.786 0.781 0.775 0.768 0.760 0.751 0.741 0.729 0.713 0.692 0.677 1.214

continues

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 291

0.5h

0.5h

h3

4

5

Wind

θ

1

2

Wind

θ

h Wind

0.5h 0.5h

3 4

5 54

3

1

2

3

4

5

54

3

h 0.5h

0.5h

Wind

1 2

3 4

5

5

4

3

h

0.5h 0.5h

Wind

1

h θ

Wind

2

h θ

Wind

3 4

Wind

5

h 0.5h

0.5h

θ

1

2

Wind

2

Flat Roof (θ < 10 deg)

Gable Roof

Hip Roof

Monoslope Roof

4

h

Wind

3

5

0.5h 0.5h

Mansard Roof

Table 27.5-2 (Continued). Main Wind Force Resisting System, Part 2 [h ≤ 160 ft (h ≤ 48.8 m)]: Enclosed Simple Diaphragm Buildings—Wind Pressures—Roofs

continues

292 STANDARD ASCE/SEI 7-16

T ab

le 27

.5 -2

(C o n ti n u ed

). M ai n W in d F o rc e R es

is ti n g S ys

te m , P ar t 2 [h

≤ 16

0 ft (h

≤ 48

.8 m )] : E n cl o se

d S im

p le

D ia p h ra g m

B u ild

in g s—

W in d P re ss

u re s—

R o o fs

E xp

o su

re C : h = 14

0– 16

0 ft , V = 11

0– 12

0 m i∕ h

V (

m i/h

) 11

0 11

5 12

0

h (f

t)

R oo

f Sl

op e

L oa

d C

as e

Z on

e Z

on e

Z on

e 1

2 3

4 5

1 2

3 4

5 1

2 3

4 5

16 0

F la

t <

2: 12

( 9.

46 °)

1

N A

N

A

−3 9.

0 −3

4. 8

−2 8.

5 N

A

N A

−4

2. 6

−3 8.

0 −3

1. 2

N A

N

A

−4 6.

4 −4

1. 4

−3 3.

9 2

N A

N

A

0. 0

0. 0

0. 0

N A

N

A

0. 0

0. 0

0. 0

N A

N

A

0. 0

0. 0

0. 0

3: 12

( 14

.0 °)

1

−3 8.

3 −2

6. 0

− 3 9.

0 − 3

4. 8

− 2 8.

5 − 4

1. 8

− 3 0.

1 −4

2. 6

−3 8.

0 −3

1. 2

−4 5.

5 −3

1. 0

−4 6.

4 −4

1. 4

−3 3.

9 2

5. 5

− 7 .8

0. 0

0. 0

0. 0

6. 0

−8 .5

0. 0

0. 0

0. 0

6. 6

−9 .2

0. 0

0. 0

0. 0

4: 12

( 18

.4 °)

1

− 3 1.

5 − 2

5. 4

−3 9.

0 −3

4. 8

−2 8.

5 −3

4. 4

−2 7.

7 −4

2. 6

−3 8.

0 −3

1. 2

−3 7.

4 −3

0. 2

−4 6.

4 −4

1. 4

−3 3.

9 2

10 .9

−1

1. 1

0. 0

0. 0

0. 0

11 .9

−1

2. 2

0. 0

0. 0

0. 0

13 .0

−1

3. 3

0. 0

0. 0

0. 0

5: 12

( 22

.6 °)

1

− 2 5.

2 −2

5. 4

−3 9.

0 −3

4. 8

−2 8.

5 −2

7. 6

−2 7.

7 −4

2. 6

−3 8.

0 −3

1. 2

−3 0.

0 −3

0. 2

−4 6.

4 −4

1. 4

−3 3.

9 2

14 .5

−1

2. 1

0. 0

0. 0

0. 0

15 .8

−1

3. 3

0. 0

0. 0

0. 0

17 .3

−1

4. 4

0. 0

0. 0

0. 0

6: 12

( 26

.6 °)

1

−2 0.

3 −2

5. 4

−3 9.

0 −3

4. 8

−2 8.

5 −2

2. 2

−2 7.

7 −4

2. 6

−3 8.

0 −3

1. 2

−2 4.

1 −3

0. 2

−4 6.

4 −4

1. 4

−3 3.

9 2

16 .0

− 1

2. 1

0. 0

0. 0

0. 0

17 .5

−1

3. 3

0. 0

0. 0

0. 0

19 .0

−1

4. 4

0. 0

0. 0

0. 0

9: 12

( 36

.9 °)

1

− 1 1.

7 − 2

5. 4

−3 9.

0 −3

4. 8

−2 8.

5 −1

2. 8

−2 7.

7 −4

2. 6

−3 8.

0 −3

1. 2

−1 4.

0 −3

0. 2

−4 6.

4 −4

1. 4

−3 3.

9 2

19 .1

− 1

2. 1

0. 0

0. 0

0. 0

20 .9

−1

3. 3

0. 0

0. 0

0. 0

22 .8

−1

4. 4

0. 0

0. 0

0. 0

12 :1

2 (4

5. 0°

) 1

−6 .6

−2 5.

4 −3

9. 0

−3 4.

8 −2

8. 5

−7 .2

−2 7.

7 −4

2. 6

−3 8.

0 −3

1. 2

−7 .9

−3 0.

2 −4

6. 4

−4 1.

4 −3

3. 9

2 19

.1

−1 2.

1 0.

0 0.

0 0.

0 20

.9

−1 3.

3 0.

0 0.

0 0.

0 22

.8

−1 4.

4 0.

0 0.

0 0.

0 15

0 F

la t

< 2:

12 (

9. 46

°)

1 N

A

N A

−3

8. 5

−3 4.

3 −2

8. 1

N A

N

A

−4 2.

0 −3

7. 5

−3 0.

7 N

A

N A

−4

5. 8

−4 0.

8 −3

3. 5

2 N

A

N A

0.

0 0.

0 0.

0 N

A

N A

0.

0 0.

0 0.

0 N

A

N A

0.

0 0.

0 0.

0 3:

12 (

14 .0

°)

1 −3

7. 7

−2 5.

7 −3

8. 5

−3 4.

3 −2

8. 1

−4 1.

3 −2

9. 7

−4 2.

0 −3

7. 5

−3 0.

7 −4

4. 9

−3 0.

5 −4

5. 8

−4 0.

8 −3

3. 5

2 5.

4 − 7

.7 0.

0 0.

0 0.

0 6.

0 −8

.4 0.

0 0.

0 0.

0 6.

5 −9

.1 0.

0 0.

0 0.

0 4:

12 (

18 .4

°)

1 −3

1. 0

−2 5.

0 −3

8. 5

−3 4.

3 −2

8. 1

−3 3.

9 −2

7. 4

−4 2.

0 −3

7. 5

−3 0.

7 −3

6. 9

−2 9.

8 −4

5. 8

−4 0.

8 −3

3. 5

2 10

.7

−1 1.

0 0.

0 0.

0 0.

0 11

.7

−1 2.

0 0.

0 0.

0 0.

0 12

.8

−1 3.

1 0.

0 0.

0 0.

0 5:

12 (

22 .6

°)

1 −2

4. 9

−2 5.

0 −3

8. 5

−3 4.

3 −2

8. 1

−2 7.

2 −2

7. 4

−4 2.

0 −3

7. 5

−3 0.

7 −2

9. 6

−2 9.

8 −4

5. 8

−4 0.

8 −3

3. 5

2 14

.3

−1 2.

0 0.

0 0.

0 0.

0 15

.6

−1 3.

1 0.

0 0.

0 0.

0 17

.0

−1 4.

3 0.

0 0.

0 0.

0 6:

12 (

26 .6

°)

1 −2

0. 0

−2 5.

0 −3

8. 5

−3 4.

3 −2

8. 1

−2 1.

9 −2

7. 4

−4 2.

0 −3

7. 5

−3 0.

7 −2

3. 8

−2 9.

8 −4

5. 8

−4 0.

8 −3

3. 5

2 15

.8

−1 2.

0 0.

0 0.

0 0.

0 17

.3

−1 3.

1 0.

0 0.

0 0.

0 18

.8

−1 4.

3 0.

0 0.

0 0.

0 9:

12 (

36 .9

°)

1 − 1

1. 6

− 2 5.

0 −3

8. 5

−3 4.

3 −2

8. 1

−1 2.

7 −2

7. 4

−4 2.

0 −3

7. 5

−3 0.

7 −1

3. 8

−2 9.

8 −4

5. 8

−4 0.

8 −3

3. 5

2 18

.9

−1 2.

0 0.

0 0.

0 0.

0 20

.6

−1 3.

1 0.

0 0.

0 0.

0 22

.5

− 1 4.

3 0.

0 0.

0 0.

0 12

:1 2

(4 5.

0° )

1 −6

.5 − 2

5. 0

−3 8.

5 −3

4. 3

−2 8.

1 −7

.1 −2

7. 4

−4 2.

0 −3

7. 5

−3 0.

7 −7

.8 −2

9. 8

−4 5.

8 −4

0. 8

−3 3.

5 2

18 .9

−1

2. 0

0. 0

0. 0

0. 0

20 .6

− 1

3. 1

0. 0

0. 0

0. 0

22 .5

− 1

4. 3

0. 0

0. 0

0. 0

14 0

F la

t <

2: 12

( 9.

46 °)

1

N A

N

A

−3 7.

9 −3

3. 8

−2 7.

7 N

A

N A

−4

1. 4

−3 6.

9 −3

0. 3

N A

N

A

−4 5.

1 −4

0. 2

−3 3.

0 2

N A

N

A

0. 0

0. 0

0. 0

N A

N

A

0. 0

0. 0

0. 0

N A

N

A

0. 0

0. 0

0. 0

3: 12

( 14

.0 °)

1

−3 7.

2 −2

5. 3

−3 7.

9 −3

3. 8

−2 7.

7 −4

0. 7

−2 9.

3 −4

1. 4

−3 6.

9 −3

0. 3

−4 4.

3 −3

0. 1

−4 5.

1 −4

0. 2

−3 3.

0 2

5. 4

− 7 .5

0. 0

0. 0

0. 0

5. 9

− 8 .2

0. 0

0. 0

0. 0

6. 4

− 9 .0

0. 0

0. 0

0. 0

4: 12

( 18

.4 °)

1

−3 0.

6 −2

4. 7

−3 7.

9 −3

3. 8

−2 7.

7 −3

3. 4

−2 7.

0 −4

1. 4

−3 6.

9 −3

0. 3

−3 6.

4 −2

9. 4

−4 5.

1 −4

0. 2

−3 3.

0 2

10 .6

−1

0. 8

0. 0

0. 0

0. 0

11 .6

−1

1. 8

0. 0

0. 0

0. 0

12 .6

−1

2. 9

0. 0

0. 0

0. 0

5: 12

( 22

.6 °)

1

− 2 4.

5 − 2

4. 7

−3 7.

9 −3

3. 8

−2 7.

7 −2

6. 8

−2 7.

0 −4

1. 4

−3 6.

9 −3

0. 3

−2 9.

2 −2

9. 4

−4 5.

1 −4

0. 2

−3 3.

0 2

14 .1

−1

1. 8

0. 0

0. 0

0. 0

15 .4

− 1

2. 9

0. 0

0. 0

0. 0

16 .8

− 1

4. 0

0. 0

0. 0

0. 0

6: 12

( 26

.6 °)

1

− 1 9.

7 − 2

4. 7

−3 7.

9 −3

3. 8

−2 7.

7 −2

1. 5

−2 7.

0 −4

1. 4

−3 6.

9 −3

0. 3

−2 3.

5 −2

9. 4

−4 5.

1 −4

0. 2

−3 3.

0 2

15 .6

−1

1. 8

0. 0

0. 0

0. 0

17 .0

− 1

2. 9

0. 0

0. 0

0. 0

18 .5

− 1

4. 0

0. 0

0. 0

0. 0

9: 12

( 36

.9 °)

1

−1 1.

4 −2

4. 7

−3 7.

9 −3

3. 8

−2 7.

7 −1

2. 5

−2 7.

0 −4

1. 4

−3 6.

9 −3

0. 3

−1 3.

6 −2

9. 4

−4 5.

1 −4

0. 2

−3 3.

0 2

18 .6

−1

1. 8

0. 0

0. 0

0. 0

20 .3

− 1

2. 9

0. 0

0. 0

0. 0

22 .1

−1

4. 0

0. 0

0. 0

0. 0

12 :1

2 (4

5. 0°

) 1

−6 .4

−2 4.

7 −3

7. 9

−3 3.

8 −2

7. 7

−7 .0

−2 7.

0 −4

1. 4

−3 6.

9 −3

0. 3

−7 .7

−2 9.

4 −4

5. 1

−4 0.

2 −3

3. 0

2 18

.6

−1 1.

8 0.

0 0.

0 0.

0 20

.3

−1 2.

9 0.

0 0.

0 0.

0 22

.1

−1 4.

0 0.

0 0.

0 0.

0

co nt in ue

s

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 293

T ab

le 27

.5 -2

(C o n ti n u ed

). M ai n W in d F o rc e R es

is ti n g S ys

te m , P ar t 2 [h

≤ 16

0 ft (h

≤ 48

.8 m )] : E n cl o se

d S im

p le

D ia p h ra g m

B u ild

in g s—

W in d P re ss

u re s—

R o o fs

E xp

o su

re C : h = 14

0– 16

0 ft , V = 13

0– 15

0 m i∕ h

V (

m i/h

) 13

0 14

0 15

0

h (f

t)

R oo

f Sl

op e

L oa

d C

as e

Z on

e Z

on e

Z on

e 1

2 3

4 5

1 2

3 4

5 1

2 3

4 5

16 0

F la

t <

2: 12

( 9.

46 °)

1

N A

N

A

−5 4.

5 −4

8. 6

−3 9.

8 N

A

N A

−6

3. 2

−5 6.

3 −4

6. 2

N A

N

A

−7 2.

5 −6

4. 6

−5 3.

0 2

N A

N

A

0. 0

0. 0

0. 0

N A

N

A

0. 0

0. 0

0. 0

N A

N

A

0. 0

0. 0

0. 0

3: 12

( 14

.0 °)

1

− 5 3.

4 − 3

6. 3

− 5 4.

5 − 4

8. 6

− 3 9.

8 −6

2. 0

−4 2.

1 −6

3. 2

−5 6.

3 −4

6. 2

−7 1.

1 −4

8. 4

−7 2.

5 −6

4. 6

−5 3.

0 2

7. 7

− 1 0.

8 0.

0 0.

0 0.

0 8.

9 − 1

2. 6

0. 0

0. 0

0. 0

10 .3

− 1

4. 4

0. 0

0. 0

0. 0

4: 12

( 18

.4 °)

1

−4 3.

9 −3

5. 5

−5 4.

5 −4

8. 6

− 3 9.

8 − 5

1. 0

− 4 1.

1 − 6

3. 2

−5 6.

3 −4

6. 2

−5 8.

5 −4

7. 2

− 7 2.

5 − 6

4. 6

− 5 3.

0 2

15 .2

−1

5. 6

0. 0

0. 0

0. 0

17 .6

−1

8. 1

0. 0

0. 0

0. 0

20 .2

−2

0. 7

0. 0

0. 0

0. 0

5: 12

( 22

.6 °)

1

− 3 5.

2 − 3

5. 5

− 5 4.

5 − 4

8. 6

−3 9.

8 −4

0. 9

−4 1.

1 −6

3. 2

−5 6.

3 −4

6. 2

−4 6.

9 −4

7. 2

−7 2.

5 −6

4. 6

−5 3.

0 2

20 .2

−1

7. 0

0. 0

0. 0

0. 0

23 .5

−1

9. 7

0. 0

0. 0

0. 0

27 .0

−2

2. 6

0. 0

0. 0

0. 0

6: 12

( 26

.6 °)

1

− 2 8.

3 − 3

5. 5

− 5 4.

5 −4

8. 6

−3 9.

8 −3

2. 8

−4 1.

1 −6

3. 2

−5 6.

3 −4

6. 2

−3 7.

7 −4

7. 2

−7 2.

5 −6

4. 6

−5 3.

0 2

22 .4

− 1

7. 0

0. 0

0. 0

0. 0

25 .9

−1

9. 7

0. 0

0. 0

0. 0

29 .8

−2

2. 6

0. 0

0. 0

0. 0

9: 12

( 36

.9 °)

1

−1 6.

4 −3

5. 5

−5 4.

5 −4

8. 6

− 3 9.

8 − 1

9. 0

− 4 1.

1 − 6

3. 2

− 5 6.

3 −4

6. 2

−2 1.

8 − 4

7. 2

− 7 2.

5 −6

4. 6

−5 3.

0 2

26 .7

− 1

7. 0

0. 0

0. 0

0. 0

31 .0

−1

9. 7

0. 0

0. 0

0. 0

11 .4

−2

2. 6

0. 0

0. 0

0. 0

12 :1

2 (4

5. 0°

) 1

−9 .2

−3 5.

5 −5

4. 5

−4 8.

6 −3

9. 8

−1 0.

7 −4

1. 1

−6 3.

2 −5

6. 3

−4 6.

2 −1

2. 3

−4 7.

2 −7

2. 5

−6 4.

6 −5

3. 0

2 26

.7

− 1 7.

0 0.

0 0.

0 0.

0 31

.0

− 1 9.

7 0.

0 0.

0 0.

0 35

.6

−2 2.

6 0.

0 0.

0 0.

0 15

0 F

la t

< 2:

12 (

9. 46

°)

1 N

A

N A

−5

3. 7

−4 7.

9 −3

9. 3

N A

N

A

−6 2.

3 −5

5. 6

−4 5.

6 N

A

N A

−7

1. 5

−6 3.

8 −5

2. 3

2 N

A

N A

0.

0 0.

0 0.

0 N

A

N A

0.

0 0.

0 0.

0 N

A

N A

0.

0 0.

0 0.

0 3:

12 (

14 .0

°)

1 − 5

2. 7

− 3 5.

8 − 5

3. 7

− 4 7.

9 −3

9. 3

−6 1.

1 −4

1. 6

−6 2.

3 − 5

5. 6

−4 5.

6 −7

0. 2

− 4 7.

7 − 7

1. 5

− 6 3.

8 − 5

2. 3

2 7.

6 −1

0. 7

0. 0

0. 0

0. 0

8. 8

−1 2.

4 0.

0 0.

0 0.

0 10

.1

− 1 4.

2 0.

0 0.

0 0.

0 4:

12 (

18 .4

°)

1 −4

3. 3

−3 5.

0 −5

3. 7

−4 7.

9 −3

9. 3

−5 0.

3 −4

0. 6

−6 2.

3 −5

5. 6

−4 5.

6 −5

7. 7

−4 6.

6 −7

1. 5

−6 3.

8 −5

2. 3

2 15

.0

−1 5.

4 0.

0 0.

0 0.

0 17

.4

−1 7.

8 0.

0 0.

0 0.

0 20

.0

−2 0.

4 0.

0 0.

0 0.

0 5:

12 (

22 .6

°)

1 −3

4. 8

−3 5.

0 −5

3. 7

−4 7.

9 −3

9. 3

−4 0.

3 −4

0. 6

−6 2.

3 −5

5. 6

−4 5.

6 −4

6. 3

−4 6.

6 −7

1. 5

−6 3.

8 −5

2. 3

2 20

.0

−1 6.

7 0.

0 0.

0 0.

0 23

.2

−1 9.

4 0.

0 0.

0 0.

0 26

.6

−2 2.

3 0.

0 0.

0 0.

0 6:

12 (

26 .6

°)

1 − 2

7. 9

− 3 5.

0 −5

3. 7

−4 7.

9 −3

9. 3

−3 2.

4 −4

0. 6

−6 2.

3 −5

5. 6

−4 5.

6 −3

7. 2

−4 6.

6 −7

1. 5

−6 3.

8 −5

2. 3

2 22

.1

− 1 6.

7 0.

0 0.

0 0.

0 25

.6

−1 9.

4 0.

0 0.

0 0.

0 29

.4

−2 2.

3 0.

0 0.

0 0.

0 9:

12 (

36 .9

°)

1 −1

6. 2

−3 5.

0 −5

3. 7

−4 7.

9 −3

9. 3

−1 8.

8 −4

0. 6

−6 2.

3 −5

5. 6

−4 5.

6 −2

1. 5

−4 6.

6 −7

1. 5

−6 3.

8 −5

2. 3

2 26

.4

− 1 6.

7 0.

0 0.

0 0.

0 30

.6

−1 9.

4 0.

0 0.

0 0.

0 11

.3

−2 2.

3 0.

0 0.

0 0.

0 12

:1 2

(4 5.

0° )

1 −9

.1 −3

5. 0

−5 3.

7 −4

7. 9

−3 9.

3 −1

0. 6

−4 0.

6 −6

2. 3

−5 5.

6 −4

5. 6

−1 2.

1 −4

6. 6

−7 1.

5 −6

3. 8

−5 2.

3 2

26 .4

−1

6. 7

0. 0

0. 0

0. 0

30 .6

− 1

9. 4

0. 0

0. 0

0. 0

35 .1

− 2

2. 3

0. 0

0. 0

0. 0

14 0

F la

t <

2: 12

( 9.

46 °)

1

N A

N

A

−5 3.

0 −4

7. 2

−3 8.

7 N

A

N A

− 6

1. 4

− 5 4.

8 −4

4. 9

N A

N

A

− 7 0.

5 − 6

2. 9

− 5 1.

5 2

N A

N

A

0. 0

0. 0

0. 0

N A

N

A

0. 0

0. 0

0. 0

N A

N

A

0. 0

0. 0

0. 0

3: 12

( 14

.0 °)

1

−5 2.

0 −3

5. 3

−5 3.

0 −4

7. 2

−3 8.

7 −6

0. 3

−4 1.

0 −6

1. 4

−5 4.

8 −4

4. 9

−6 9.

2 −4

7. 0

−7 0.

5 −6

2. 9

−5 1.

5 2

7. 5

−1 0.

5 0.

0 0.

0 0.

0 8.

7 −1

2. 2

0. 0

0. 0

0. 0

10 .0

−1

4. 0

0. 0

0. 0

0. 0

4: 12

( 18

.4 °)

1

−4 2.

7 −3

4. 5

−5 3.

0 −4

7. 2

−3 8.

7 −4

9. 5

−4 0.

0 −6

1. 4

−5 4.

8 −4

4. 9

−5 6.

9 −4

5. 9

−7 0.

5 −6

2. 9

−5 1.

5 2

14 .8

−1

5. 1

0. 0

0. 0

0. 0

17 .2

−1

7. 6

0. 0

0. 0

0. 0

19 .7

−2

0. 2

0. 0

0. 0

0. 0

5: 12

( 22

.6 °)

1

−3 4.

3 −3

4. 5

−5 3.

0 −4

7. 2

−3 8.

7 −3

9. 7

−4 0.

0 −6

1. 4

−5 4.

8 −4

4. 9

−4 5.

6 −4

5. 9

−7 0.

5 −6

2. 9

−5 1.

5 2

19 .7

−1

6. 5

0. 0

0. 0

0. 0

22 .8

−1

9. 1

0. 0

0. 0

0. 0

26 .2

−2

1. 9

0. 0

0. 0

0. 0

6: 12

( 26

.6 °)

1

−2 7.

5 −3

4. 5

−5 3.

0 −4

7. 2

−3 8.

7 −3

1. 9

−4 0.

0 −6

1. 4

−5 4.

8 −4

4. 9

−3 6.

6 −4

5. 9

−7 0.

5 −6

2. 9

−5 1.

5 2

21 .7

−1

6. 5

0. 0

0. 0

0. 0

25 .2

− 1

9. 1

0. 0

0. 0

0. 0

28 .9

− 2

1. 9

0. 0

0. 0

0. 0

9: 12

( 36

.9 °)

1

−1 5.

9 −3

4. 5

−5 3.

0 −4

7. 2

−3 8.

7 −1

8. 5

−4 0.

0 −6

1. 4

−5 4.

8 − 4

4. 9

− 2 1.

2 −4

5. 9

−7 0.

5 −6

2. 9

−5 1.

5 2

26 .0

− 1

6. 5

0. 0

0. 0

0. 0

30 .1

− 1

9. 1

0. 0

0. 0

0. 0

11 .1

−2

1. 9

0. 0

0. 0

0. 0

12 :1

2 (4

5. 0°

) 1

−9 .0

−3 4.

5 − 5

3. 0

− 4 7.

2 − 3

8. 7

− 1 0.

4 − 4

0. 0

− 6 1.

4 − 5

4. 8

−4 4.

9 −1

2. 0

−4 5.

9 −7

0. 5

−6 2.

9 −5

1. 5

2 26

.0

−1 6.

5 0.

0 0.

0 0.

0 30

.1

− 1 9.

1 0.

0 0.

0 0.

0 34

.6

−2 1.

9 0.

0 0.

0 0.

0

co nt in ue

s

294 STANDARD ASCE/SEI 7-16

T ab

le 27

.5 -2

(C o n tin

u ed

). M ai n W in d F o rc e R es

is ti n g S ys

te m , P ar t 2 [h

≤ 16

0 ft (h

≤ 48

.8 m )] : E n cl o se

d S im

p le

D ia p h ra g m

B u ild

in g s—

W in d P re ss

u re s—

R o o fs

E xp

o su

re C : h = 14

0– 16

0 ft , V = 16

0– 20

0 m i∕ h

V

( m

i/h )

16

0 18

0 20

0 h (f t)

R

oo f

Sl op

e L

oa d

C as

e Z

on e

Z on

e Z

on e

1 2

3 4

5 1

2 3

4 5

1 2

3 4

5 16

0 F

la t

< 2:

12 (

9. 46

°)

1 N

A

N A

−8

2. 5

−7 3.

6 −6

0. 3

N A

N

A

−1 04

.4 −9

3. 1

−7 6.

3 N

A

N A

−1

28 .9

−1 14

.9 − 9

4. 3

2 N

A

N A

0.

0 0.

0 0.

0 N

A

N A

0.

0 0.

0 0.

0 N

A

N A

0.

0 0.

0 0.

0 3:

12 (

14 .0

°)

1 −8

0. 9

−5 8.

3 −8

2. 5

−7 3.

6 − 6

0. 3

−1 02

.5 −6

9. 6

−1 04

.4 −9

3. 1

−7 6.

3 −1

26 .5

−8 6.

0 −1

28 .9

−1 14

.9 −9

4. 3

2 11

.7

− 1 6.

4 0.

0 0.

0 0.

0 14

.8

−2 0.

8 0.

0 0.

0 0.

0 18

.2

−2 5.

7 0.

0 0.

0 0.

0 4:

12 (

18 .4

°)

1 − 6

6. 5

−5 3.

7 −8

2. 5

− 7 3.

6 −6

0. 3

−8 4.

2 − 6

8. 0

−1 04

.4 −9

3. 1

−7 6.

3 −1

04 .0

−8 3.

9 − 1

28 .9

−1 14

.9 −9

4. 3

2 23

.0

− 2 3.

6 0.

0 0.

0 0.

0 29

.2

−2 9.

8 0.

0 0.

0 0.

0 36

.0

−3 6.

8 0.

0 0.

0 0.

0 5:

12 (

22 .6

°)

1 −5

3. 4

−5 3.

7 −8

2. 5

− 7 3.

6 −6

0. 3

−6 7.

6 − 6

8. 0

−1 04

.4 − 9

3. 1

− 7 6.

3 −8

3. 4

−8 3.

9 − 1

28 .9

−1 14

.9 −9

4. 3

2 30

.7

−2 5.

7 0.

0 0.

0 0.

0 38

.8

−3 2.

5 0.

0 0.

0 0.

0 47

.9

−4 0.

1 0.

0 0.

0 0.

0 6:

12 (

26 .6

°)

1 −4

2. 9

−5 3.

7 −8

2. 5

− 7 3.

6 −6

0. 3

−5 4.

3 −6

8. 0

−1 04

.4 −9

3. 1

−7 6.

3 −6

7. 0

−8 3.

9 −1

28 .9

−1 14

.9 −9

4. 3

2 33

.9

−2 5.

7 0.

0 0.

0 0.

0 42

.9

−3 2.

5 0.

0 0.

0 0.

0 52

.9

−4 0.

1 0.

0 0.

0 0.

0 9:

12 (

36 .9

°)

1 − 2

4. 8

−5 3.

7 −8

2. 5

−7 3.

6 −6

0. 3

−3 1.

4 −6

8. 0

−1 04

.4 − 9

3. 1

−7 6.

3 −3

8. 8

−8 3.

9 −1

28 .9

−1 14

.9 − 9

4. 3

2 40

.5

−2 5.

7 0.

0 0.

0 0.

0 51

.2

− 3 2.

5 0.

0 0.

0 0.

0 63

.2

−4 0.

1 0.

0 0.

0 0.

0 12

:1 2

(4 5.

0° )

1 − 1

4. 0

−5 3.

7 −8

2. 5

−7 3.

6 −6

0. 3

−1 7.

7 −6

8. 0

−1 04

.4 − 9

3. 1

−7 6.

3 −2

1. 9

−8 3.

9 −1

28 .9

−1 14

.9 − 9

4. 3

2 40

.5

− 2 5.

7 0.

0 0.

0 0.

0 51

.2

−3 2.

5 0.

0 0.

0 0.

0 63

.2

−4 0.

1 0.

0 0.

0 0.

0 15

0 F

la t

< 2:

12 (

9. 46

°)

1 N

A

N A

−8

1. 4

−7 2.

6 − 5

9. 5

N A

N

A

− 1 03

.0 − 9

1. 8

−7 5.

3 N

A

N A

−1

27 .2

− 1 13

.4 − 9

3. 0

2 N

A

N A

0.

0 0.

0 0.

0 N

A

N A

0.

0 0.

0 0.

0 N

A

N A

0.

0 0.

0 0.

0 3:

12 (

14 .0

°)

1 −7

9. 9

−5 7.

5 −8

1. 4

− 7 2.

6 −5

9. 5

−1 01

.1 − 6

8. 7

−1 03

.0 −9

1. 8

−7 5.

3 −1

24 .8

− 8 4.

8 − 1

27 .2

−1 13

.4 −9

3. 0

2 11

.5

−1 6.

2 0.

0 0.

0 0.

0 14

.6

−2 0.

5 0.

0 0.

0 0.

0 18

.0

−2 5.

3 0.

0 0.

0 0.

0 4:

12 (

18 .4

°)

1 − 6

5. 7

−5 3.

0 −8

1. 4

−7 2.

6 −5

9. 5

−8 3.

1 − 6

7. 1

−1 03

.0 −9

1. 8

− 7 5.

3 −1

02 .6

−8 2.

8 − 1

27 .2

−1 13

.4 −9

3. 0

2 22

.7

−2 3.

3 0.

0 0.

0 0.

0 28

.8

− 2 9.

4 0.

0 0.

0 0.

0 35

.5

−3 6.

4 0.

0 0.

0 0.

0 5:

12 (

22 .6

°)

1 −5

2. 7

−5 3.

0 −8

1. 4

− 7 2.

6 −5

9. 5

−6 6.

7 − 6

7. 1

−1 03

.0 −9

1. 8

−7 5.

3 −8

2. 3

−8 2.

8 −1

27 .2

−1 13

.4 −9

3. 0

2 30

.3

−2 5.

3 0.

0 0.

0 0.

0 38

.3

− 3 2.

1 0.

0 0.

0 0.

0 47

.3

−3 9.

6 0.

0 0.

0 0.

0 6:

12 (

26 .6

°)

1 − 4

2. 3

−5 3.

0 −8

1. 4

−7 2.

6 −5

9. 5

− 5 3.

5 −6

7. 1

−1 03

.0 − 9

1. 8

−7 5.

3 −6

6. 1

−8 2.

8 −1

27 .2

−1 13

.4 − 9

3. 0

2 33

.4

−2 5.

3 0.

0 0.

0 0.

0 42

.3

− 3 2.

1 0.

0 0.

0 0.

0 52

.2

−3 9.

6 0.

0 0.

0 0.

0 9:

12 (

36 .9

°)

1 − 2

4. 5

−5 3.

0 −8

1. 4

−7 2.

6 − 5

9. 5

− 3 1.

0 −6

7. 1

− 1 03

.0 − 9

1. 8

−7 5.

3 − 3

8. 3

−8 2.

8 −1

27 .2

− 1 13

.4 −9

3. 0

2 39

.9

−2 5.

3 0.

0 0.

0 0.

0 50

.5

−3 2.

1 0.

0 0.

0 0.

0 62

.4

−3 9.

6 0.

0 0.

0 0.

0 12

:1 2

(4 5.

0° )

1 − 1

3. 8

−5 3.

0 −8

1. 4

−7 2.

6 − 5

9. 5

− 1 7.

5 −6

7. 1

− 1 03

.0 − 9

1. 8

−7 5.

3 − 2

1. 6

−8 2.

8 −1

27 .2

− 1 13

.4 −9

3. 0

2 39

.9

− 2 5.

3 0.

0 0.

0 0.

0 50

.5

−3 2.

1 0.

0 0.

0 0.

0 62

.4

−3 9.

6 0.

0 0.

0 0.

0 14

0 F

la t

< 2:

12 (

9. 46

°)

1 N

A

N A

−8

0. 2

−7 1.

5 −5

8. 6

N A

N

A

−1 01

.5 −9

0. 5

−7 4.

2 N

A

N A

− 1

25 .3

−1 11

.7 −9

1. 6

2 N

A

N A

0.

0 0.

0 0.

0 N

A

N A

0.

0 0.

0 0.

0 N

A

N A

0.

0 0.

0 0.

0 3:

12 (

14 .0

°)

1 − 7

8. 7

−5 6.

7 −8

0. 2

− 7 1.

5 −5

8. 6

−9 9.

6 − 6

7. 7

−1 01

.5 −9

0. 5

− 7 4.

2 −1

23 .0

−8 3.

6 − 1

25 .3

−1 11

.7 −9

1. 6

2 11

.4

−1 6.

0 0.

0 0.

0 0.

0 14

.4

− 2 0.

2 0.

0 0.

0 0.

0 17

.7

−2 4.

9 0.

0 0.

0 0.

0 4:

12 (

18 .4

°)

1 − 6

4. 7

−5 2.

2 −8

0. 2

−7 1.

5 −5

8. 6

− 8 1.

9 −6

6. 1

−1 01

.5 − 9

0. 5

−7 4.

2 − 1

01 .1

−8 1.

6 −1

25 .3

−1 11

.7 −9

1. 6

2 22

.4

−2 2.

9 0.

0 0.

0 0.

0 28

.4

−2 9.

0 0.

0 0.

0 0.

0 35

.0

−3 5.

8 0.

0 0.

0 0.

0 5:

12 (

22 .6

°)

1 − 5

1. 9

−5 2.

2 −8

0. 2

−7 1.

5 −5

8. 6

− 6 5.

7 −6

6. 1

−1 01

.5 − 9

0. 5

−7 4.

2 −8

1. 1

−8 1.

6 −1

25 .3

−1 11

.7 −9

1. 6

2 29

.8

− 2 5.

0 0.

0 0.

0 0.

0 37

.7

−3 1.

6 0.

0 0.

0 0.

0 46

.6

−3 9.

0 0.

0 0.

0 0.

0 6:

12 (

26 .6

°)

1 −4

1. 7

−5 2.

2 −8

0. 2

−7 1.

5 −5

8. 6

−5 2.

8 −6

6. 1

−1 01

.5 −9

0. 5

−7 4.

2 −6

5. 2

−8 1.

6 −1

25 .3

−1 11

.7 −9

1. 6

2 32

.9

−2 5.

0 0.

0 0.

0 0.

0 41

.7

−3 1.

6 0.

0 0.

0 0.

0 51

.4

−3 9.

0 0.

0 0.

0 0.

0 9:

12 (

36 .9

°)

1 −2

4. 1

−5 2.

2 −8

0. 2

−7 1.

5 − 5

8. 6

−3 0.

6 −6

6. 1

−1 01

.5 −9

0. 5

−7 4.

2 −3

7. 7

−8 1.

6 −1

25 .3

−1 11

.7 −9

1. 6

2 39

.4

−2 5.

0 0.

0 0.

0 0.

0 49

.8

−3 1.

6 0.

0 0.

0 0.

0 61

.5

−3 9.

0 0.

0 0.

0 0.

0 12

:1 2

(4 5.

0° )

1 −1

3. 6

−5 2.

2 −8

0. 2

−7 1.

5 −5

8. 6

−1 7.

2 −6

6. 1

−1 01

.5 −9

0. 5

−7 4.

2 −2

1. 3

−8 1.

6 −1

25 .3

−1 11

.7 −9

1. 6

2 39

.4

−2 5.

0 0.

0 0.

0 0.

0 49

.8

− 3 1.

6 0.

0 0.

0 0.

0 61

.5

−3 9.

0 0.

0 0.

0 0.

0

co nt in ue

s

Minimum Design Loads and Associated Criteria for Buildings and Other Structures 295