13-52-170 Impact loading.

   The live loads specified in Section 13-52-090 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.

   (a)   Elevators. All elevator loads shall be increased by 100 percent for impact, and the structural supports shall be designed within the limits of deflection prescribed by ASME A17.1 as adopted by Chapter 14C-3.

   (b)   Machinery. For the purpose of design, the weight of machinery and moving loads shall be increased as follows to allow for impact: (1) elevator machinery, 100 percent; (2) light machinery, shaft- or motor-driven, 20 percent; (3) reciprocating machinery or power-driven units, 50 percent; (4) hangers for floors or balconies, 33 percent. All percentages shall be increased if so recommended by the manufacturer.

   (c)   Craneways. All craneways except those using only manually powered cranes shall have their design loads increased for impact as follows: (1) a vertical force equal to 25 percent of the maximum wheel load; (2) a lateral force equal to 20 percent of the weight of the trolley and lifted load only, applied one-half at the top of each rail; and (3) a longitudinal force of ten percent of the maximum wheel loads of the crane applied at the top of the rail.

   (d)   Exception. Reductions in these loads may be permitted if substantiating technical data acceptable to the building commissioner is provided.

(Prior code § 68-2.10; Added Coun. J. 11-29-89, p. 8387; Amend Coun. J. 9-13-89, p. 4604; Amend Coun. J. 3-5-03, p. 104990, § 20; Amend Coun. J. 11-13-07, p. 14999, Art. II, § 1; Amend Coun. J. 3-28-18, p. 74459, Art. II, § 7)

13-52-180 Special loading.

   Driveways, sidewalks, spaces for storage of loaded or unloaded trucks or buses, and spaces to be occupied by tanks, tracks or other special equipment shall be designed for the actual weight of the superimposed loads.

(Prior code § 68-2.11; Added Coun. J. 11-29-89, p. 8387)

13-52-190 Posting of floor loads.

   (a)   In every building or other structure, or part thereof, used for mercantile industrial or storage purposes, the loads approved by the building commissioner shall be marked on placards of approved design. Such placards shall be supplied and securely affixed by the owner of the building, or his duly authorized agent, in a conspicuous place in each space to which they relate. Application of such placard shall be accompanied by a certification from a registered architect or registered structural engineer that he personally inspected the building and that he computed the safe load in conformity with the provisions of this ordinance. Duplicate placards may be issued to replace lost or destroyed placards without such certification upon payment of a fee in accordance with Section 13-32-320 of this Code, where the department of buildings has records of the safe floor load limits of particular buildings.

   (b)   Exceptions – Posting for floor loads shall not be required in buildings or portions thereof used exclusively for the production and distribution of electricity, gas or steam.

   (c)   Spaces in garages and parking facilities designed for the use of passenger automobiles only shall be placarded as follows: “This floor to be used for the storage of passenger automobiles only.”

(Prior code § 68-2.12; Added Coun. J. 11-29-89, p. 8387; Amend Coun. J. 9-13-89, p. 4604; Amend Coun. J. 3-5-03, p. 104990, § 20; Amend Coun. J. 11-13-07, p. 14999, Art. II, § 1)

13-52-200 Restriction on loading.

   The building owner shall ensure that a live load greater than that for which a floor or roof is approved by the Building Commissioner shall not be placed, or caused or permitted to be placed, on any floor or roof of a building or other structure.

(Prior code § 68-2.13; Added Coun. J. 11-29-89, p. 8387; Amend Coun. J. 9-13-89, p. 4604; Amend Coun. J. 3-5-03, p. 104990, § 20; Amend Coun. J. 11-13-07, p. 14999, Art. II, § 1; Amend Coun. J. 11-9-16, p. 36266, § 13)

13-52-210 Reduction in live loads.

   Permitted reduction in live loads shall comply with the provisions of subsections (a), (b) and (c) of this section.

   (a)   Permitted Reductions in Floor Construction. Beams, girders and trusses shall be designed to carry not less than the following percentage of the live floor loads established in Section 13-52-090 or based on the tributary floor area and influence area carried by the members.

      1.   For live loads of 100 pounds per square foot or less:

 

Tributary Area In Square Feet	Influence Area	Percentage of Live Load
less than 200	400	100
300	600	86
400	800	78
600	1,200	68
800	1,600	63
greater than 800	greater than 1,600	60

 

      2.   Linear interpolation between tabulated percentage of live loads is permitted.

      3.   For live loads that exceed 100 pounds per square foot no reduction is permitted.

      4.   No reduction is allowed for areas to be occupied as places of public assembly, garages or parking facilities, one way slabs or joists.

   (b)   Permitted reductions in bearing walls, columns, piers and other members supporting more than one floor shall be based on the tributary area and influence area carried by the member.

      1.   For live loads of 100 pounds per square foot or less:

 

Tributary Area In Square Feet	Influence Area	Percentage of Live Load
less than 200	800	100
300	1,200	68
400	1,600	63
600	2,400	56
800	3,200	52
900 and greater	3,600 and greater	50

 

      2.   Linear interpolation between tabulated percentage of live loads is permitted.

      3.   No reduction is allowed for areas to be occupied as places of public assembly or for roofs. For garages and parking facilities see (4).

      4.   For live loads that exceed 100 pounds per square foot, and in garages and parking facilities for passenger vehicles only, members supporting more than one floor may be designed to carry not less than 80 percent of the live loads established in Section 13-52-090.

   (c)   Tributary Area/Influence Area. The influence area is defined as that floor area over which the influence surface for structural effects is significantly different from zero. For columns this is four times the traditional tributary area, while for flexural members it is two times. For an interior column, for instance, the influence area is the total area of the four surrounding bays, while for an interior girder it is the total area of the two contributing bays. Edge columns and girders have half the influence area of the respective interior members (two days for columns, one for girders), while a corner column has an influence area of one bay. For unusual plan configurations, the concept of significant influence effect should be applied. For multiple floors, areas for members supporting more than one floor are summed.

(Prior code § 68-2.14; Added Coun. J. 11-29-89, p. 8387)

13-52-220 Roof loads.

   Wind load, snow load and rain load are environmental loads. Live loads on a roof are those produced (1) during maintenance by workers, equipment and materials. Reductions in roof live loads and/or environmental roof loads shall not be permitted. Design roof loads shall be determined by the provisions of Sections 13-52-230 to 13-52-290 inclusive, 13-52-350 and 13-52-380.

(Prior code § 68-3; Added Coun. J. 11-29-89, p. 8387; 6-14-95, p. 2841)

13-52-230 Minimum roof live loads.

   Roofs shall be designed for a live load of 15 pounds per square foot on the horizontal projection or for other controlling combination of environmental loads.

(Prior code § 68-3.1; Added Coun. J. 11-29-89, p. 8387)