Structural Loads and Procedures
Structural Design Requirements
(1)Except as otherwise provided in this Section, the structural design of farm buildings shall conform to Part 4.
(2)Except as provided in Sentence (3), farm buildings shall be classified in the Low Importance Category as described in Table 4.1.2.1.
(3)Liquid manure storage tanks shall be classified in the Normal Importance Category as described in Table 4.1.2.1.
(4)In lieu of the requirements of Article 4.2.2.1., a subsurface investigation of the farm building site is permitted to be carried out by a suitably qualified person prior to or during construction.
Loads Due to Use and Occupancy
(1)In addition to the requirements of Article 4.1.5.3., the specified live load supported on a floor or suspended from a ceiling shall be not less than the applicable value listed in Table 2.3.2.1.
| Type of Load | Minimum Specified Live Load on Area of Floor or Ceiling, kPa | Minimum Specified Live Load on Floor Slats, kN/m |
|---|---|---|
| Cattle | 5.0 | 4.5 |
| Sheep | 2.5 | 2.0 |
| Swine | 3.5 | 2.5 |
| Horses | 5.0 | – |
| Poultry | 2.0 | – |
| Greenhouses | 2.5 | – |
(1)Areas designed for the accumulation of poultry manure, such as solid floors and dropping pits under a wire floor, slotted floor or cage, shall be designed for a specified live load of not less than 1 kPa for each 100 mm depth of manure.
(2)Where machinery or vehicles not exceeding 1 000 kg in gross weight are used for manure clean-out in a poultry barn, the barn floor shall be designed for a specified two-wheel live load of not less than 6 kN in addition to the specified live load prescribed in Sentence (1).
(1)Floors supporting stored products shall be designed for the specified live load due to their intended use and occupancy, but not for less than 5 kPa.
(1)The specified uniformly distributed live load on an area of floor used for farm machinery or vehicles shall be
- (a) for farm machinery and vehicles not exceeding 4 000 kg in gross weight, not less than 2.4 kPa,
- (b) for farm machinery and vehicles exceeding 4 000 kg but not exceeding 9 000 kg in gross weight, not less than 6 kPa, and
- (c) for farm machinery and vehicles exceeding 9 000 kg in gross weight, not less than 12 kPa.
(2)The specified live load due to possible concentrations of load resulting from the use of an area of floor for farm machinery or vehicles shall comply with Article 4.1.5.9.
(3)Where an area of floor is used for processing or for loading or unloading of vehicles, the minimum specified live loads prescribed in Sentences (1) and (2) shall be increased by 50% for the area.
(0.1)Liquid manure storage tanks shall be constructed of steel, reinforced concrete or prestressed concrete.
(1)Tops of liquid manure storage tanks that are accessible to vehicular traffic or used as a floor in a farm building shall be designed for the loads due to their intended use and occupancy.
(2)Tops of liquid manure storage tanks that are located outdoors but not exposed to vehicular traffic shall be designed for the dead load plus the snow and rain loads prescribed in Subsection 4.1.6. or for the dead load plus 2 kPa, whichever produces the most critical effect.
(3)Walls and partitions of liquid manure storage tanks shall be designed for
- (a) an internal lateral pressure based on an equivalent fluid density of 10 kN/m3 for liquid manure, and
- (b) the anticipated internal lateral ice pressure.
(4)Vertical external walls of liquid manure storage tanks located below ground level shall be designed for
- (a) the anticipated lateral earth pressure, which shall not be used to reduce the effects of the internal lateral pressures specified in Sentence (3), and
- (b) a lateral surcharge load of 5 kPa, applied uniformly below ground level, where earth within 1.5 m of the walls is subject to vehicular loads.
(5)Concrete for liquid manure storage tanks shall
- (a) be made from HS or HSb cement,
- (b) have a 28-day strength of at least 32 MPa, and
- (c) have a water/cement materials ratio of not more than 0.45.
(6)Liquid manure storage tank walls, bases and appurtenances, including piping for the conveyance of liquid manure and associated connections and joints, shall be designed and constructed to minimize leakage of liquid manure.
(7)Liquid manure storage tanks shall be placed on undisturbed soil free of any organic, deleterious and extraneous materials and capable of supporting the superimposed design loads from the tanks.
(8)Where granular fills are used between the bases of liquid manure storage tanks and the undisturbed soil, the granular fills shall be compacted to a Standard Proctor density of not less than 95%.
Loads Due to Snow
(1)For unobstructed slippery roofs of farm buildings with a roof slope, α, greater than 15° but not greater than 60° from the horizontal, where snow and ice can slide completely off the roof, the slope factor, Cs shall be calculated as follows:
(1)In a farm building classified as a Group G, Division 3 major occupancy where heating and drainage systems are installed to prevent the accumulation of snow and water, the supporting structure for the light-transmitting roof areas is permitted to be designed for a specified roof snow load of not less than 1 kPa, provided
- (a) the heating system is capable of maintaining a minimum interior temperature of 10°C throughout the farm building, and
- (b) an emergency power supply is provided that (i) is supplied from a power source such as batteries, a generator, or a combination thereof, and (ii) will continue to supply power to the heating system in the event that the regular power supply to the farm building is interrupted.
Loads Due to Earthquakes
(1)Farm buildings need not be designed for loads due to earthquakes in accordance with Subsection 4.1.8. where
- (a) the Seismic Category is SC1, or
- (b) the Seismic Category is SC2, and the RdRo value of the seismic force resisting system (SFRS) is equal to or greater than 3.0.
(2)For the purpose of Sentence (1), the Seismic Category is permitted to be determined on the basis of IES(0.2) alone.
(3)For the purpose of Sentences (1) and (2), the Seismic Category is permitted to be determined by assigning Site Class D without carrying out a subsurface investigation.