GENERAL DESIGN REQUIREMENTS

1604.3 Serviceability. Structural systems and members thereof shall be designed to have adequate stiffness to limit deflections as indicated in Table 1604.3. Drift limits applicable to earthquake loading shall be in accordance with ASCE 7 Chapter 12, 13, 15 or 16, as applicable. See Section 12.12.1 of ASCE 7 for drift limits applicable to earthquake loading. 126 TABLE 1604.3 DEFLECTION LIMITS a,b,c,h,l CONSTRUCTION L or L, S or W D+Ld.g Roof members:e Supporting plaster or stucco ceiling Supporting 1/3601/2401/ 1/3601/2401/ 1/2401/1801/ nonplaster ceiling 180 180 120 Not supporting ceiling Floor members l / 360 1/ 240 Exterior walls: With plaster or stucco finishes With other 1/3601/2401/ brittle finishes With flexible finishes 120 - - Interior partitions:ᵇ With plaster or stucco finishes With other 1/3601/2401/ brittle finishes With flexible finishes 120 Farm buildings l/ 180 Greenhouses 1/ 120 For SI: 1 foot = 304.8 mm. a. For structural roofing and siding made of formed metal sheets, the total load deflection shall not exceed 60. For secondary roof structural members supporting formed metal roofing, the live load deflection shall not exceed 1/ 150. For secondary wall members supporting formed metal siding, the design wind load deflection shall not exceed 1/90. For roofs, this exception only applies when the metal sheets have no roof covering. b. Flexible, folding and portable partitions and interior partitions not exceeding 6 feet in height are not governed by the provisions of this section. The deflection criterion for interior partitions is based on the horizontal load defined in Section 1607.15. c. See Section 2403 for glass supports. d. The deflection limit for the D+(L+Lr) load combination only applies to the deflection due to the creep component of long-term dead load deflection plus the short-term live load deflection. For lumber, structural glued laminated timber, prefabricated wood I-joists and structural composite lumber members that are dry at time of installation and used under dry conditions in accordance with the ANSI/AWC NDS, the creep component of the long-term deflection shall be permitted to be estimated as the immediate dead load deflection resulting from 0.5D. For lumber and glued laminated timber members installed or used at all other moisture conditions or cross laminated timber and wood structural panels that are dry at time of installation and used under dry conditions in accordance with the ANSI/AWC NDS, the creep component of the long-term deflection is permitted to be estimated as the immediate dead load deflection resulting from D. The value of 0.5D shall not be used in combination with ANSI/AWC NDS provisions for long-term loading. e. The preceding deflections do not ensure against ponding. Roofs that do not have sufficient slope or camber to ensure adequate drainage shall be investigated for ponding. See Chapter 8 of ASCE 7. f. The wind load shall be permitted to be taken as 0.42 times the "component and cladding" loads or directly calculated using the 10-year mean return interval wind speed for the purpose of determining deflection limits in Table 1604.3. Where framing members support glass, the deflection limit therein shall not exceed that specified in Section 1604.3.7 g. For steel structural members, the detection due to creep component of long-term dead load shall be permitted to be taken as zero. h. For aluminum structural members or aluminum panels used in skylights and sloped glazing framing, roofs or walls of sunroom additions or patio covers not supporting edge of glass or aluminum sandwich panels, the total load deflection shall not exceed 60. For continuous aluminum structural members supporting edge of glass, the total load deflection shall not exceed 175 for each glass lite or 60 for the entire length of the member, whichever is more stringent. For aluminum sandwich panels used in roofs or walls of sunroom additions or patio covers, the total load deflection shall not exceed 1/120. i. l = Length of the member between supports. For cantilever members, l shall be taken as twice the length of the cantilever. 127 1604.4 Analysis. Load effects on structural members and their connections shall be determined by methods of structural analysis that take into account equilibrium, general stability, geometric compatibility and both short-and long-term material properties. Members that tend to accumulate residual deformations under repeated service loads shall have included in their analysis the added eccentricities expected to occur during their service life. Any system or method of construction to be used shall be based on a rational analysis in accordance with well-established principles of mechanics. Such analysis shall result in a system that provides a complete load path capable of transferring loads from their point of origin to the load-resisting elements. The total lateral force shall be distributed to the various vertical elements of the lateral forceresisting system in proportion to their rigidities, considering the rigidity of the horizontal bracing system or diaphragm. Rigid elements assumed not to be a part of the lateral force-resisting system are permitted to be incorporated into buildings provided that their effect on the action of the system is considered and provided for in the design. A diaphragm is rigid for the purpose of distribution of story shear and torsional moment when the lateral deformation of the diaphragm is less than or equal to two times the average story drift. Where required by ASCE 7, provisions shall be made for the increased forces induced on resisting elements of the structural system resulting from torsion due to eccentricity between the center of application of the lateral forces and the center of rigidity of the lateral force-resisting system Every structure shall be designed to resist the overturning effects caused by the lateral forces specified in this chapter. See Section 1609 for wind loads, Section 1610 for lateral soil loads and Section 1613 for earthquake loads. The use of reinforced concrete walls with slabs acting as frames, in their weak (out-of-plane) direction, to withstand lateral forces as part of lateral force resisting system, is not permitted. 128 TABLE 1607.1 TABLE 1607.1-continued MINIMUM UNIFORMLY DISTRIBUTED LIVE LOADS, L₀, MINIMUM UNIFORMLY DISTRIBUTED LIVE LOADS, Lo, AND MINIMUM CONCENTRATED LIVE LOADS AND MINIMUM CONCENTRATED LIVE LOADSg UNIFOR CONCENTRAT UNIFORM CONCENTRATED OCCUPANCY OR USE OCCUPANCY OR USE M ED (pounds) (psf) (pounds) 1. Apartments (see residential) - - 23. Penal institutions 2. Access floor systems Cell blocks 40 - Office use 50 2,000 Corridors 100 Computer use 100 2,000 3. Armories and drill rooms 150ⁿ 24. Recreational uses: - Bowling alleys, poolrooms and 75m - 4. Assembly areas similar uses 100m Fixed seats (fastened to 60ᵐ Dance halls and ballrooms 100m floor) Follow spot, Gymnasiums 250n projections and 50 Ice skating rink control - Reviewing stands, grandstands and 100ᶜ m 100ᵐ rooms Lobbies 100ᵐ bleachers 100m Movable seats 150n Roller skating rink Stage floors 100ᵐ Stadiums and arenas with fixed 60c, 1.5 times the live load for the 25. Residential - 5. Balconies and decks One- and two-family dwellings 10 area served, not - required to Uninhabitable attics without 20 exceed 100 storage¹ 30 6. Catwalks 40 300 Uninhabitable attics with storage¹, j, 20 60 - Habitable attics and sleeping areas 40 7. Cornices 8. Corridors Canopies, including marquees All other areas 40 First floor 100 Other Same as Hotels and multifamily dwellings - Private rooms and corridors 100 floors occupancy serving them served except as Public rooms and corridors indicated 9. Dining rooms and restaurants 100ᵐ - 26. Roofs 10. Dwellings (see residential) - - Flat roofs with rise less 1 unit 11. Elevator machine room vertical in 24 units horizontal 30 and controlroom grating - 300 (on area of 2 inches by 2 inches) (slope less than 4.2%) 12. Finish light floor plate construction All roof surfaces subject to - 200 maintenance workers 5ᵐ 300 (on area of 1 inch by 1 inch) Awnings and canopies: 13. Fire escapes 100 20 2,000 - Fabric construction supported by a On single-family dwellings only 40 300 skeleton structure 14. Garages (passenger vehicles 20 40° Note a All other construction, except one- and Note 1 only) Trucks and buses See Section 1607 7 two-family dwellings 15. Handrails, guards and grab bars See Section 1607.8 Ordinary flat, pitched, and curved roofs 100 16. Helipads See Section 1607.6 (that are not occupiable) Primary roof 100m 17. Hospitals members exposed to a Note 1 work floor Corridors above first floor 80 1,000 Operating rooms, 60 1,000 Single panel point of lower chord of laboratories Patient rooms 40 1,000 roof trusses or any point along 18. Hotels (see residential) primary structural members - | 19. Libraries supporting roofs over manufacturing, Corridors above first floor 80 1,000 storage warehouses, and repair Reading rooms 60 1,000 garages Stack rooms 150b, 1.000 All other primary roof members 20. Manufacturing Occupiable roofs: Heavy 250n 3,000 Roof gardens Light 2,000 27. Schools 21. Marquees, except one- and 75 - Classrooms 40 1,000 two-family dwellings Corridors above first floor 80 1,000 22. Office buildings First-floor corridors 100 1,000 Corridors above first floor 80 2,000 File and computer rooms shall 28. Scuttles, skylight ribs and accessible | - - 200 be designed for heavier loads ceilings based on anticipated 29. Sidewalks, vehicular driveways and 250d, n 8,000e occupancy Lobbies and first-floor 100 2,000 yards, subject to trucking 30. Stairs and exits (continued) One- and two-family dwellings 40 300f All other 100 300f (continued) 129 TABLE 1607.1-continued MINIMUM UNIFORMLY DISTRIBUTED LIVE LOADS, Lo, AND MINIMUM CONCENTRATED LIVE LOADS UNIFORM CONCENTRATED OCCUPANCY OR USE (psf) (pounds) 31. Storage warehouses (shall be designed for heavier loads if required for 250n - anticipated storage) 125" Heavy Light 32. Stores Retail 100 1,000 First floor 75 1,000 Upper floors 125" 1,000 Wholesale, all floors 33. Vehicle barriers See Section 1607.9 34. Walkways and elevated platforms 60 - (other than exitways) 35. Yards and terraces, pedestrians 100m - For SI: 1 inch = 25.4 mm, 1 square inch = 645.16 mm₂, 1 square foot = 0.0929 m2, 1 pound per square foot = 0.0479 kN/m₂, 1 pound = 0.004448 kN, 1 pound per cubic foot = 16 kg/m3. 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 41/2inches by /2inches; (2) for mechanical parking structures without slab or deck that 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. 3. Parallel rows of double-faced book stacks shall be separated by aisles not less than 36 inches wide. c. Design in accordance with ICC 300. d. Other uniform loads in accordance with an approved method containing provisions for truck loadings shall be considered where appropriate. 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 building official (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 or 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 not less than 30 inches. ii. The slopes of the joists or truss bottom chords are not 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. 1. Areas of occupiable roofs, other than roof gardens and assembly areas, shall be designed for appropriate loads as approved by the building official. 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. 130