N.Y.C. Admin. Code § BC 1607: Section BC 1607: Live Loads

1607.1 General.

Live loads are those loads defined in Chapter 2 of this code.

Table 1607.1 Minimum Uniformly Distributed Live Loads, L

O

, and Minimum Concentrated Live Loads

g

Occupancy or Use

Uniform (psf)

Concentrated pounds)

1. Apartments (see residential)

—

—

2. Access floor systems

Office use

50

2,000

Computer use

100

2,000

3. Armories and drill rooms

150

n

—

4. Assembly areas

—

Fixed seats (fastened to floor)

60

m

Follow spot, projections and control rooms

50

Lobbies

100

m

Movable seats

100

m

Private assembly spaces, including conference rooms

50

Stages floors

150

n

Platforms (assembly)

100

m

Other assembly spaces

100

m

5. Balconies and Decks

h

1.5 times the live load for the occupancy served. Not required to exceed 100 psf

—

6. Catwalks

40

300

7. Cornices

60

—

8. Corridors

—

First floor

100

Other floors

Same as occupancy served except as indicated

9. Dining rooms and restaurants

100

m

—

10. Dwellings (see residential)

—

—

11. Elevator machine room and control room grating (on area of 2 inches by 2 inches)

—

300

12. Equipment rooms, including pump rooms, generator rooms, transformer vaults, and areas for switch gear, ventilating, air conditioning, and similar electrical and mechanical equipment

75

—

13. Finish light floor plate construction (on area of 1 inch by 1 inch)

—

200

14. Fire escapes (Exterior)

100

—

On single-family dwellings only

40

15. Garages (passenger vehicles only)

40

o

Note a

Trucks and buses

See Section 1607.7

16. Handrails, guards and grab bars

See Section 1607.8

17. Helipads

See Section 1607.6

18. Hospitals

Corridors above first floor

80

1,000

Operating rooms, laboratories

60

1,000

Patient rooms

40

1,000

19. Hotels (see residential)

—

—

20. Libraries

Corridors above first floor

80

1,000

Reading rooms

60

1,000

Stack rooms

150

b, n

1,000

21. Manufacturing

Heavy

250

n

3,000

Light

125

n

2,000

22. Marquees, except one- and two-family dwellings

75

—

23. Office buildings

Corridors above first floor

80

2,000

File and computer rooms shall be designed for heavier loads based on anticipated occupancy

—

—

Lobbies and first-floor corridors

100

2,000

Offices

50

2,000

24. Penal Institutions

—

Cell blocks

40

Corridors

100

25. Recreational uses:

—

Bowling alleys, poolrooms and similar uses

75

m

Dance halls and ballrooms

100

m

Gymnasiums

100

m

Ice skating rink

250

n

Reviewing stands, grandstands and bleachers

100

c, m

Roller skating rink

100

m

Stadiums and arenas with fixed seats (fastened to floor)

60

c, m

26. Residential

—

One- and two-family dwellings

Uninhabitable attics without storage

i

10

Uninhabitable attics with storage

i, j, k

20

Habitable attics and sleeping areas

k

30

Canopies, including marquees

20

All other areas

40

Hotels and multifamily dwellings

Private rooms and corridors serving them

40

Public rooms and corridors serving them

100

27. Roofs

All roof surfaces subject to maintenance workers

300

Awnings and canopies:

Fabric construction supported by a skeleton structure

5

m

All other construction, except one- and two-family dwellings

20

Ordinary flat, pitched, and curved roofs (that are not occupiable)

20

Primary roof members exposed to a work floor

Single panel point of lower chord of roof trusses or any point along primary structural members supporting roofs over manufacturing, storage warehouses, and repair garages

2,000

All other primary roof members

300

Occupiable roofs:

Roof gardens

100

Assembly areas

100

m

All other similar areas

Note l

Note l

28. Schools

Classrooms

40

1,000

Corridors above first floor

80

1,000

First-floor corridors

100

1,000

29. Scuttles, skylight ribs and accessible ceilings

—

200

30. Sidewalks, vehicular driveways and yards, subject to trucking

300

d, m

8,000

e

or 20,000

d

31. Stairs and exits

One- and two-family dwellings

40

300

f

All other

100

300

f

32. Storage warehouses (shall be designed for heavier loads if required for anticipated storage)

—

Heavy

250

n

Light

125

n

33. Stores

Retail

First floor

100

1,000

Upper floors

75

1,000

Wholesale, all floors

125

n

1,000

34. Vehicle barriers

See Section 1607.9

35. Walkways and elevated platforms (other than exitways)

60

—

36. Yards and terraces, pedestrians

100

m

—

For SI: 1 inch = 25.4 mm, 1 square inch = 645.16 mm

2

, 1 square foot = 0.0929 m

2

, 1 pound per square foot = 0.0479 kN/m

2

, 1 pound = 0.004448 kN, 1 pound per cubic foot = 16 kg/m

3

.

a. Floors in garages or portions of buildings used for the storage of motor vehicles shall be designed for the uniformly distributed live loads of this Table or the following concentrated loads: (1) for garages restricted to passenger vehicles accommodating not more than nine passengers, 3,000 pounds acting on an area of 4 1/2 inches by 4 1/2 inches; (2) for mechanical parking structures without slab or deck which are used for storing passenger vehicles only, 2,250 pounds per wheel.

b. The loading applies to stack room floors that support nonmobile, double-faced library book stacks, subject to the following limitations:

1. The nominal book stack unit height shall not exceed 90 inches;

2. The nominal shelf depth shall not exceed 12 inches for each face; and

3. Parallel rows of double-faced book stacks shall be separated by aisles not less than 36 inches wide.

c. Design in accordance with Section 1029.1.

d. The concentrated wheel load of 20,000 pounds shall be applied as follows 8,000 pounds on an area of 20 square inches, 20,000 pounds on a 20 inch by 10 inch area.

e. The concentrated wheel load shall be applied on an area of 4.5 inches by 4.5 inches.

f. The minimum concentrated load on stair treads shall be applied on an area of 2 inches by 2 inches. This load need not be assumed to act concurrently with the uniform load.

g. Where snow loads occur that are in excess of the design conditions, the structure shall be designed to support the loads due to the increased loads caused by drift buildup or a greater snow design determined by the department (see Section 1608).

h. See Section 1604.8.3 for decks attached to exterior walls.

i. Uninhabitable attics without storage are those where the maximum clear height between the joists and rafters is less than 42 inches, or where there are not two or more adjacent trusses with web configurations capable of accommodating an assumed rectangle 42 inches in height by 24 inches in width, or greater, within the plane of the trusses. This live load need not be assumed to act concurrently with any other live load requirements.

j. Uninhabitable attics with storage are those where the maximum clear height between the joists and rafters is 42 inches or greater, or where there are two or more adjacent trusses with web configurations capable of accommodating an assumed rectangle 42 inches in height by 24 inches in width, or greater, within the plane of the trusses.

The live load need only be applied to those portions of the joists of truss bottom chords where both of the following conditions are met:

i. The attic area is accessible from an opening not less than 20 inches in width by 30 inches in length that is located where the clear height in the attic is a minimum of 30 inches; and

ii. The slopes of the joists or truss bottom chords are no greater than two units vertical in 12 units horizontal.

The remaining portions of the joists or truss bottom chords shall be designed for a uniformly distributed concurrent live load of not less than 10 pounds per square foot.

k. Attic spaces served by stairways other than the pull-down type shall be designed to support the minimum live load specified for habitable attics and sleeping rooms.

l. Areas of occupiable roofs, other than roof gardens and assembly areas, shall be designed for appropriate loads as approved by the department. Unoccupied landscaped areas of roofs shall be designed in accordance with Section 1607.13.3.

m. Live load reduction is not permitted.

n. Live Load reduction is only permitted in accordance with Section 1607.11.1.2 or Item 1 of Section 1607.11.2.

o. Live Load reduction is only permitted in accordance with Section 1607.11.1.3 or Item 2 of Section 1607.11.2.

1607.2 Loads not specified.

For occupancies or uses not designated in Table 1607.1, the live load shall be determined in accordance with a method approved by the commissioner.

1607.2.1 Stage areas using scenery or scenic elements.

Scenery battens and suspension systems shall be designed for a load of 30 pounds per linear foot (437.7 N/m) of batten length. Loft block and head block beams shall be designed to support vertical and horizontal loads corresponding to a 4 inch (101.6 mm) spacing of battens for the entire depth of the gridiron. Direction and magnitude of total forces shall be determined from the geometry of the rigging system including load concentrations from spot line rigging. Locking rails shall be designed for a uniform uplift of 500 psf (3447 kN/m

2

) with a 1,000 pound (454 kg) concentration. Impact factor for batten design shall be 75 percent and for loft and head block beams shall be 25 percent. A plan drawn to a scale not less than 1/4 inch (6.4 mm) equals one foot (304.8 mm) shall be displayed in the stage area indicating the framing plan of the rigging loft and the design loads for all members used to support scenery or rigging. Gridirons over stages shall be designed to support a uniformly distributed live load of 50 psf (2.40 kN/m

2

) in addition to the rigging loads indicated.

1607.3 Uniform 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 live loads given in Table 1607.1.

1607.4 Concentrated live loads.

Floors, roofs and other similar surfaces shall be designed to support the uniformly distributed live loads prescribed in Section 1607.3 or the concentrated live loads, given in Table 1607.1, whichever produces the greater load effects. Unless otherwise specified, the indicated concentration shall be assumed to be uniformly distributed over an area of 2 1/2 feet by 2 1/2 feet (762 mm by 762 mm) and shall be located so as to produce the maximum load effects in the structural members.

1607.5 Partition loads.

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 construction documents, unless the specified live load is 80 psf (3.83 kN/m

2

) or greater. Weights of all partitions shall be considered, using either actual weights at locations shown on the plans or the equivalent uniform load given in Section 1607.5.2. Partition loads shall be taken as superimposed dead loads.

Table 1607.5 Equivalent Uniform Partition Loads

Partition Weight (plf)

Equivalent Uniform Load (psf) (to be added to floor dead and live loads)

50 or less

0

51 to 100

6

101 to 200

12

201 to 350

20

Greater than 350

20 plus a concentrated live load of the weight in excess of 350 pfl.

For SI: 1 pound per linear foot = 0.01459 kN/m

2

, 1 pound per square foot = 0.0479 kN/m

2

.

Where actual partition weights are used, the uniform design live load may be omitted from the strip of floor area under each partition.

1607.5.2 Equivalent uniform load.

The equivalent uniform partition loads in Table 1607.5 may be used in lieu of actual partition weights except for bearing partitions or partitions in toilet room areas (other than in one- and two-family dwellings), at stairs and elevators, and similar areas where partitions are concentrated. In such cases, actual partition weights shall be used in design.

1607.6 Helipads.

Helipads shall be designed for the following live loads:

1. A uniform live load, L, as specified in Items 1.1 and 1.2. This load shall not be reduced.

1.1. 40 psf (1.92 kN/m

2

) where the design basis helicopter has a maximum take-off weight of 3,000 pounds (13.35 kN) or less.

1.2. 60 psf (2.87 kN/m

2

) where the design basis helicopter has a maximum take-off weight greater than 3,000 pounds (13.35 kN).

2. A single concentrated live load, L, of 3,000 pounds (13.35 kN) applied over an area of 4.5 inches by 4.5 inches (114.3 mm by 114.3 mm) and located so as to produce the maximum load effects on the structural elements under consideration. The concentrated load is not required to act concurrently with other uniform or concentrated live loads.

3. Two single concentrated live loads, L, 8 feet (2438.4 mm) apart applied on the landing pad (representing the helicopter's two main landing gear, whether skid type or wheeled type), each having a magnitude of 0.75 times the maximum take-off weight of the helicopter, and located so as to produce the maximum load effects on the structural elements under consideration. The concentrated loads shall be applied over an area of 8 inches by 8 inches (203.2 mm by 203.2 mm) and are not required to act concurrently with other uniform or concentrated live loads.

Landing areas designed for a design basis helicopter with maximum take-off weight of 3,000-pounds (13.35 kN) shall be identified with a 3,000 pound (13.34 kN) weight limitation. The landing area weight limitation shall be indicated by the numeral "3" (kips) located in the bottom right corner of the landing area as viewed from the primary approach path. The indication for the landing area weight limitation shall be a minimum 5 feet (1524 mm) in height.

1607.7 Heavy vehicle loads.

Floors and other surfaces that are intended to support vehicle loads greater than a 10,000 pound (4535.9 kg) gross vehicle weight rating shall comply with Sections 1607.7.1 through 1607.7.5.

1607.7.1 Loads.

Where any structure does not restrict access for vehicles that exceed a 10,000 pound (4535.9 kg) gross vehicle weight rating, those portions of the structure subject to such loads shall be designed using the vehicular live loads, including consideration of impact and fatigue, in accordance with the NYSDOT Bridge Manual and the NYSDOT LRFD Bridge Design Specifications.

Alternatively, it shall be acceptable to utilize the design live loads for sidewalks as shown in Table 1607.1.

1607.7.2 Fire truck and emergency vehicles.

Where a structure or portions of a structure are designated as fire access roads as defined in Chapter 5 of the New York City Fire Code, the structure shall be designed for the live loading specified in Section 1607.7.1 of this code or those identified in Chapter 5 of the New York City Fire Code, whichever produces the greater load effects.

1607.7.3 Heavy vehicle garages.

Garages designed to accommodate vehicles that exceed a 10,000 pound (4535.9 kg) gross vehicle weight rating, shall be designed using the live loading specified by Section 1607.7.1. Vertical impact shall be taken as 10 percent of the vertical load.

Exception: The vehicular live loads and load placement are allowed to be determined using the actual vehicle weights for the vehicles allowed onto the garage floors, provided such loads and placement are based on rational engineering principles and are approved by the department, but shall not be less than 50 psf (2.9 kN/m

2

). This live load shall not be reduced.

1607.7.4 Forklifts and movable equipment.

Where a structure is intended to have forklifts or other movable equipment present, the structure shall be designed for the total vehicle or equipment load and the individual wheel loads for the anticipated vehicles as specified by the owner of the facility. These loads shall be posted in accordance with Section 1607.7.5.

1607.7.4.1 Impact and fatigue.

Impact loads and fatigue loading shall be considered in the design of the supporting structure. For the purposes of design, the vehicle and wheel loads shall be increased by 30 percent to account for impact.

1607.7.5 Posting.

The maximum weight of vehicles allowed into or on a garage or other structure shall be posted by the owner or the owner's authorized agent in accordance with Article 118 of Chapter 1 of Title 28 of the Administrative Code.

1607.8 Loads on handrails, guards, grab bars, and seats.

Handrails and guards shall be designed and constructed for the structural loading conditions set forth in Section 1607.8.1. Grab bars, shower seats and accessible benches shall be designed and constructed for the structural loading conditions set forth in Section 1607.8.2.

1607.8.1 Handrails and guards.

Handrails and guards shall be designed to resist a linear load of 50 pounds per linear foot (plf) (0.73 kN/m) in accordance with Section 4.5.1.1 of ASCE 7. Glass handrail assemblies and guards shall also comply with Section 2407.

Exceptions:

1. For one- and two-family dwellings, only the single concentrated load required by Section 1607.8.1.1 shall be applied.

2. In Group I-3, F, H and S occupancies, for areas that are not accessible to the general public and that have an occupant load no greater than 50, the minimum load shall be 20 pounds per foot (0.29 kN/m).

1607.8.1.1 Concentrated load.

Handrails and guards shall be designed to resist a concentrated load of 200 pounds (0.89 kN) in accordance with Section 4.5.1.1 of ASCE 7.

1607.8.1.2 Intermediate rails.

Intermediate rails (all those except the handrail), balusters and panel fillers shall be designed to resist a concentrated load of 50 pounds (0.22 kN) in accordance with Section 4.5.1.1 of ASCE 7, a vertically downward load of 50 pounds per foot (0.73 kN/m), and a concentrated upward load of 50 pounds (0.22 kN) applied at the most critical location. Reactions due to this loading are not required to be applied simultaneously with one another, and are not required to be superimposed with those of Section 1607.8.1 or 1607.8.1.1. The railings, balusters and components shall be designed separately for the effect of wind when the total wind load on the panel or component exceeds 50 pounds (0.22 kN). The wind load need not be combined with any other live load.

1607.8.2 Grab bars, shower seats and dressing room bench seats.

Grab bars, shower seats and dressing room bench seats shall be designed to resist a single concentrated load of 250 pounds (1.11 kN) applied in any direction at any point on the grab bar or seat so as to produce the maximum load effects.

1607.9 Vehicle barriers.

Vehicle barriers for passenger vehicles shall be designed to resist a concentrated load of 6,000 pounds (26.70 kN) in accordance with Section 4.5.3 of ASCE 7.

Garages accommodating trucks and buses shall be designed in accordance with an approved method that contains provisions for traffic railings.

1607.9.1 Columns in parking areas.

Unless specially protected, columns in parking areas subject to impact of moving vehicles shall be designed to resist the lateral load due to impact. For passenger vehicles, this lateral load shall be taken as a minimum service live load of 6,000 pounds (26.70 kN) applied at least 1 foot 6 inches (457.2 mm) above the roadway, and acting simultaneously with other design loads. In addition, columns in parking areas shall meet the requirements of Section 1616 for structural integrity. Vehicle barrier systems in garages accommodating trucks and buses shall be designed in accordance with NYSDOT Bridge Manual and the NYSDOT LRFD Bridge Design Specifications.

1607.10 Impact loads.

The live loads specified in Sections 1607.3 through 1607.9 shall be assumed to include adequate allowance for impact conditions. Provisions shall be made in the structural design for uses and loads that involve unusual vibration and impact forces.

1607.10.1 Elevators.

Members, elements and components subject to dynamic loads from elevators shall be designed for impact loads and deflection limits prescribed by ASME A17.1, as modified by Appendix K of this code.

1607.10.2 Machinery.

For the purpose of design, the weight of machinery and moving loads shall be increased as follows to allow for impact: (i) light machinery, shaft- or motor-driven, 20 percent; and (ii) reciprocating machinery or power-driven units, 50 percent. Percentages shall be increased where specified by the manufacturer.

1607.10.3 Elements supporting building maintenance equipment.

In addition to any other applicable live loads, structural elements that support hoists for facade access 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 greater.

Equipment installed temporarily to facilitate construction, demolition, alteration, or inspection shall be subject to the requirements of Chapter 33.

1607.10.4 Fall arrest and lifeline anchorages.

In addition to any other applicable live loads, lifeline anchorages and structural elements that support lifeline anchorages shall be designed for a live load of at least 3,100 pounds (13.8 kN) for each attached lifeline, in every direction that a fall arrest load may be applied.

1607.10.5 Railroad equipment.

Minimum loads (including vertical, lateral, longitudinal, and impact) and the distribution thereof shall meet the applicable requirements of Chapter 15 of the AREMA Manual for Railway Engineering.

1607.10.6 Assembly structures.

Seating areas in grandstands, stadiums, and similar assembly structures shall be designed to resist the simultaneous application of a horizontal swaying load of at least 24 plf (36 kg/m) of seats applied in a direction parallel to the row of the seats, and of at least 10 plf (15 kg/m) of seats in a direction perpendicular to the row of the seats. When this load is used in combination with wind for outdoor structures, the wind load shall be one-half of the design wind load.

1607.11 Reduction in uniform live loads.

Except for uniform live loads at roofs, all other minimum uniformly distributed live loads, L

o

, in Table 1607.1 are permitted to be reduced in accordance with Section 1607.11.1 or 1607.11.2. Uniform live loads at roofs are permitted to be reduced in accordance with Section 1607.13.2.

1607.11.1 Basic uniform live load reduction.

Subject to the limitations of Sections 1607.11.1.1 through 1607.11.1.4 and Table 1607.1, members for which a value of KLLAT is 400 square feet (37.16 m

2

) or more are permitted to be designed for a reduced uniformly distributed live load, L, in accordance with the following equation:

(Equation 16-30)

where:

where:

L = Reduced design live load per square foot (m2) of area supported by the member.

L

o

= Unreduced design live load per square foot (m2) of area supported by the member (see Table 1607.1).

K

LL

= Live load element factor (see Table 1607.11.1).

A

T

= Tributary area, in square feet (m

2

).

L shall not be less than 0.50L

o

for members supporting one floor and L shall not be less than 0.40L

o

for members supporting two or more floors.

Table 1607.11.1 Live Load Element Factor

K

LL

Element

K

LL

Interior columns Exterior columns without cantilever slabs

4 4

Edge columns with cantilever slabs

3

Corner columns with cantilever slabs Edge beams without cantilever slabs Interior beams

2 2 2

All other members not identified above including:

Edge beams with cantilever slabs

Cantilever beams

One-way slabs

Two-way slabs

Members without provisions for continuous shear transfer normal to their span

1

1607.11.1.1 One-way slabs.

The tributary area, A

T

, for use in Equation 16-23 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.

1607.11.1.2 Heavy live loads.

Live loads that exceed 100 psf (4.79 kN/m

2

) shall not be reduced.

Exceptions:

1. The live loads for members supporting two or more floors are permitted to be reduced by a maximum of 20 percent, but the live load shall be not less than L as calculated in Section 1607.11.1.

2. For uses other than storage, where approved, additional live load reductions shall be permitted where shown by the registered design professional that a rational approach has been used and that such reductions are warranted.

1607.11.1.3 Passenger vehicle garages.

The live loads shall not be reduced in passenger vehicle garages.

Exception: The live loads for members supporting two or more floors are permitted to be reduced by a maximum of 20 percent, but the live load shall not be less than L as calculated in Section 1607.11.1.

1607.11.1.4 Flat slab and flat plate construction.

Live loads shall not be reduced for calculating shear stresses at the heads of columns in flat slab or flat plate construction.

1607.11.2 Alternative uniform live load reduction.

As an alternative to Section 1607.11.1 and subject to the limitations of Table 1607.1, uniformly distributed live loads are permitted to be reduced in accordance with the following provisions. Such reductions shall apply to slab systems, beams, girders, columns, piers, walls and foundations.

1. A reduction shall not be permitted where the live load exceeds 100 psf (4.79 kN/m

2

) except that the design live load for members supporting two or more floors is permitted to be reduced by a maximum of 20 percent.

Exception: For uses other than storage, where approved, additional live load reductions shall be permitted where shown by the registered design professional that a rational approach has been used and that such reductions are warranted.

2. A reduction shall not be permitted in passenger vehicle parking garages except that the live loads for members supporting two or more floors are permitted to be reduced by a maximum of 20 percent.

3. For live loads not exceeding 100 psf (4.79 kN/m

2

), the design live load for any structural member supporting 150 square feet (13.94 m

2

) or more is permitted to be reduced in accordance with Equation 16-31.

4. For one-way slabs, the area, A, for use in Equation 16-31 shall not exceed the product of the slab span and a width normal to the span of 0.5 times the slab span.

R = 0.08 (A - 150)

(Equation 16-31)

For SI: R = 0.861 (A - 13.94)

Such reduction shall not exceed the smallest of:

1. 40 percent for horizontal members;

2. 60 percent for vertical members; or

3.

R as determined by the following equation.

R = 23.1 (1 + D / L

o

)

(Equation 16-32)

where:

A

= Area of floor or roof supported by the member, square feet (m

2

).

D

= Dead load per square foot (m

2

) of area supported.

L

o

= Unreduced live load per square foot (m

2

) of area supported.

R

= Reduction in percent.

1607.12 Distribution of floor loads.

Where uniform floor live loads are involved in the design of structural members arranged so as to create continuity, the minimum applied loads shall be the full dead loads on all spans in combination with the floor live loads on spans selected to produce the greatest load effect at each location under consideration. Floor live loads are permitted to be reduced in accordance with Section 1607.11.

1607.13 Roof loads.

The structural supports of roofs and marquees shall be designed to resist wind and, where applicable, snow and earthquake loads, in addition to the dead load of construction and the appropriate live loads as prescribed in this section, or as set forth in Table 1607.1. The live loads acting on a sloping surface shall be assumed to act vertically on the horizontal projection of that surface.

1607.13.1 Distribution of roof loads.

Where uniform roof live loads are reduced to less than 20 psf (0.96 kN/m

2

) in accordance with Section 1607.13.2.1 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 most unfavorable load effect. See Section 1607.13.2 for reductions in minimum roof live loads and Section 7.5 of ASCE 7 for partial snow loading.

1607.13.1.1 Arches and gabled frames.

The following simplification is permissible:

1. Live load placed on one-half of the span adjacent to one support.

2. Live load placed on the center one-fourth of the span.

3. Live load placed on 3/8 of the span adjacent to each support.

1607.13.2 General.

The minimum uniformly distributed live loads of roofs and marquees, L

o

, in Table 1607.1 are permitted to be reduced in accordance with Section 1607.13.2.1.

1607.13.2.1 Ordinary roofs, awnings and canopies.

Ordinary flat, pitched and curved roofs, and awnings and canopies other than of fabric construction supported by a skeleton structure, are permitted to be designed for a reduced uniformly distributed roof live load, L

r

, as specified in the following equations or other controlling combinations of loads as specified in Section 1605, 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 the following equations shall not be used unless approved by the commissioner. Such structures shall be designed for a minimum roof live load of 12 psf (0.58 kN/m

2

).

L

r

= L

o

R

1

R

2

(Equation 16-33)

where:

12 £ L

r

 £ 20

For SI: L

r

= L

o

R

1

R

2

where:

0.58 £ L

r

 £ 0.96

L

o

= Unreduced roof live load per square foot (m

2

) of horizontal projection supported by the member (see Table 1607.1).

L

r

= Reduced live load per square foot (m

2

) of horizontal projection supported by the member.

The reduction factors R

1

and R

2

shall be determined as follows:

R

1

= 1 for A

t

 £ 200 square feet (18.58 m

2

)

(Equation 16-34)

R

1

= 1.2 - 0.001A

t

for 200 square feet < A

t

< 600 square feet

(Equation 16-35)

For SI: 1.2 - 0.011A

t

for 18.58 square meters < A

t

< 55.74 square meters

R

t

= 0.6 for A

t

 ³ 600 square feet (55.74 m

2

)

(Equation 16-36)

where:

A

t

= Tributary area (span length multiplied by effective width) in square feet (m

2

) supported by any structural member, and

R

2

= 1 for F £ 4

(Equation 16-37)

R

2

= 1.2 - 0.05 F for 4 £ F £ 12

(Equation 16-38)

R

2

= 0.6 for F ³ 12

(Equation 16-39)

where:

F

= For a sloped roof, the number of inches of rise per foot (for SI: F = 0.12 × slope, with slope expressed as a percentage), or for an arch or dome, the rise-to-span ratio multiplied by 32.

1607.13.3 Occupiable roofs.

Areas of roofs that are occupiable, such as vegetative roofs, roof gardens or for assembly or other similar purposes, and marquees are permitted to have their uniformly distributed live loads reduced in accordance with Section 1607.11.

1607.13.3.1 Vegetative and landscaped roofs.

The weight of all landscaping materials shall be considered as dead load and shall be computed on the basis of saturation of the soil as determined in accordance with Section 3.1.4, of ASCE 7. The uniform design live load in unoccupied landscaped areas on roofs shall be 20 psf (0.958 kN/m

2

). The uniform design live load for occupied landscaped areas on roofs shall be determined in accordance with Table 1607.1 of this code.

1607.13.4 Awnings, canopies, and sun control devices.

Awnings, canopies, and sun control devices shall be designed for uniform live loads as required in Table 1607.1 as well as for snow loads and wind loads as specified in Sections 1608 and 1609.

1607.13.5 Photovoltaic panel systems.

Roof structures that provide support for photovoltaic panel systems shall be designed in accordance with Sections 1607.13.5.1 through 1607.13.5.4, as applicable.

1607.13.5.1 Roof live load.

Roof structures that support photovoltaic panel systems shall be designed to resist each of the following conditions:

1. Applicable uniform and concentrated roof loads with the photovoltaic panel system dead loads.

Exception: Roof live loads need not be applied to the area covered by photovoltaic panels where the clear space between the panels and the roof surface is 24 inches (609.6 mm) or less.

2. Applicable uniform and concentrated roof loads without the photovoltaic panel system present.

1607.13.5.2 Photovoltaic panels or modules.

The structure of a roof that supports solar photovoltaic panels or modules shall be designed to accommodate the full solar photovoltaic panels or modules and ballast dead load, including concentrated loads from support frames in combination with the loads from Section 1607.13.5.1 and other applicable loads. Where applicable, snow drift loads created by the photovoltaic panels or modules shall be included.

1607.13.5.3 Photovoltaic panels or modules installed as an independent structure.

Solar photovoltaic panels or modules that are independent structures and do not have accessible/occupied space underneath are not required to accommodate a roof photovoltaic live load, provided the area under the structure is restricted to keep the public away. All other loads and combinations in accordance with Section 1605 shall be accommodated.

Solar photovoltaic panels or modules that are designed to be the roof, span to structural supports, and have accessible/occupied space underneath shall have the panels or modules and all supporting structures designed to support a roof photovoltaic live load, as defined in Section 1607.13.5.1 in combination with other applicable loads. Solar photovoltaic panels or modules in this application are not permitted to be classified as "not accessible" in accordance with Section 1607.13.5.1.

1607.13.5.4 Ballasted photovoltaic panel systems.

Roof structures that provide support for ballasted photovoltaic panel systems shall be designed, or analyzed, in accordance with Section 1604.4; checked in accordance with Section 1604.3.6 for deflections; and checked in accordance with Section 1611 for ponding.

1607.13.6 Hanging loads.

Girders and roof trusses (other than joists) over garage areas regularly utilized for the repair of vehicles and over manufacturing floors or storage floors used for commercial purposes shall be capable of supporting, in addition to the specified live and wind loads, a concentrated live load of 2,000 pounds (907.2 kg) applied at any lower chord panel point for trusses, and at any point of the lower flange for girders.

1607.14 Crane loads.

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 of the crane and the vertical impact, lateral and longitudinal forces induced by the moving crane.

1607.14.1 Maximum wheel load.

The maximum wheel loads shall be the wheel loads produced by the weight of the bridge, as applicable, plus the sum of the rated capacity and the weight of the trolley with the trolley positioned on its runway at the location where the resulting load effect is maximum.

1607.14.2 Vertical impact force.

The maximum wheel loads of the crane shall be increased by the percentages shown below to determine the induced vertical impact or vibration force:

Monorail cranes (powered)

25 percent

Cab-operated or remotely operated bridge cranes (powered)

25 percent

Pendant-operated bridge cranes (powered)

10 percent

Bridge cranes or monorail cranes with hand-geared bridge, trolley and hoist percent

0 percent

1607.14.3 Lateral force.

The lateral force on crane runway beams with electrically powered trolleys shall be calculated as 20 percent of the sum of the rated capacity of the crane and the weight of the hoist and trolley. The lateral force shall be assumed to act horizontally at the traction surface of a runway beam, in either direction perpendicular to the beam, and shall be distributed according to the lateral stiffness of the runway beam and supporting structure.

1607.14.4 Longitudinal force.

The longitudinal force on crane runway beams, except for bridge cranes with hand-geared bridges, shall be calculated as 10 percent of the maximum wheel loads of the crane. The longitudinal force shall be assumed to act horizontally at the traction surface of a runway beam, in either direction parallel to the beam.

1607.15 Interior walls and partitions.

Interior walls and partitions that exceed 6 feet (1828.8 mm) in height, including their finish materials, shall have adequate strength and stiffness to resist the loads to which they are subjected but not less than a horizontal load of 5 psf (0.240 kN/m

2

).

1607.15.1 Fabric partitions.

Fabric partitions that exceed 6 feet (1828.8 mm) in height, including their finish materials, shall have adequate strength and stiffness to resist the following load conditions:

1. The horizontal distributed load need only be applied to the partition framing. The total area used to determine the distributed load shall be the area of the fabric face between the framing members to which the fabric is attached. The total distributed load shall be uniformly applied to such framing members in proportion to the length of each member.

2. A concentrated load of 40 pounds (0.176 kN) applied to an 8-inch diameter (203.2 mm) area of the fabric face at a height of 54 inches (1371.6 mm) above the floor.

1607.15.2 Fire Walls.

In order to meet the structural stability requirements of Section 706.2 where the structure on either side of the wall has collapsed, fire walls and their supports shall be designed to withstand a minimum horizontal allowable stress load of 5 psf (0.240 kN/m

2

).