"2. Where the allowable stress design load combinations of ASCE 7 Section 2.4 are used, flat roof snow loads of 30 pounds per square foot (1.44kN/m2) or less and roof live loads of 30 pounds per square foot (1.44kN/m2) or less need not be combined with seismic loads. Where flat roof snow loads exceed 30 pounds per square foot (1.44kN/m2), the snow loads may be reduced in accordance with the following in load combinations including both snow and seismic loads. S as calculated below, shall be combined with seismic loads.
S = (0.20 + 0.025 (A-5))Proof, where S shall be greater than or equal to 0.20Proof.
Where:
S = Weight of snow to be used in combination with seismic loads.
A = Elevation above sea level at the location of the structure (ft/1,000)
Proof = Design roof snow loads, Pf or Ps, psf
For the purpose of this section, snow load shall be assumed uniform on the horizontal projection without including the effects of drift or sliding. The Importance Factor, I, used in calculating Pf may be considered 1.0."
"4. ASCE 7-16 Section 2.3.6 Equation 6 shall be modified to 1.2D + Ev + Eh + L +f2S and 1.2D + Ev + Emh + L +f2S with f2 = (0.20 +0.025(A-5)) where the roof snow load exceeds 30 pounds per square foot (1.44kN/m2). Where A = Elevation above sea level at the location of the structure (ft/1000). f2 = 0 for roof snow loads of 30 pounds per square foot (1.44kN/m2) or less."
TABLE 7.2-9 | |||
GROUND SNOW LOADS FOR SELECTED LOCATIONS IN UTAH | |||
City/Town | County | Ground Snow Load (lb/ft2) | Elevation (ft) |
Beaver | Beaver | 35 | 5886 |
Brigham City | Box Elder | 42 | 4423 |
Castle Dale | Emery | 32 | 5669 |
Coalville | Summit | 57 | 5581 |
Duchesne | Duchesne | 39 | 5508 |
Farmington | Davis | 35 | 4318 |
Fillmore | Millard | 30 | 5138 |
Heber City | Wasatch | 60 | 5604 |
Junction | Piute | 27 | 6030 |
Kanab | Kane | 25 | 4964 |
Loa | Wayne | 37 | 7060 |
Logan | Cache | 43 | 4531 |
Manila | Daggett | 26 | 6368 |
Manti | Sanpete | 37 | 5620 |
Moab | Grand | 21 | 4029 |
Monticello | San Juan | 67 | 7064 |
Morgan | Morgan | 52 | 5062 |
Nephi | Juab | 39 | 5131 |
Ogden | Weber | 37 | 4334 |
Panguitch | Garfield | 41 | 6630 |
Parowan | Iron | 32 | 6007 |
Price | Carbon | 31 | 5558 |
Provo | Utah | 31 | 4541 |
Randolph | Rich | 50 | 6286 |
Richfield | Sevier | 27 | 5338 |
St. George | Washington | 21 | 2585 |
Salt Lake City | Salt Lake | 28 | 4239 |
Tooele | Tooele | 35 | 5029 |
Vernal | Uintah | 39 | 5384 |
Note: To convert lb/ft2 to kN/m2, multiply by 0.0479. To convert feet to meters, multiply by 0.3048. 1. Statutory requirements of the Authority Having Jurisdiction are not included in this state ground snow load table. 2. For locations where there is substantial change in altitude over the city/town, the load applies at and below the cited elevation, with a tolerance of 100 ft (30 m). 3. For other locations in Utah, see Bean, B., Maguire, M., Sun, Y. (2018), "The Utah Snow Load Study," Utah State University Civil and Environmental Engineering Faculty Publications, Paper 3589, http://utahsnowload.usu.edu/, for ground snow load values." |
4. Where flat roof snow load, Pf, exceeds 30 psf (1.44kN/m2), the snow load included in the effective seismic weight shall be calculated, in accordance with the following equation: Ws = (0.20 + 0.025(A-5))Pf >= 0.20 Pf.
WHERE:
Ws = Weight of snow to be included as effective seismic weight
A = Elevation above sea level at the location of the structure (ft./1,000)
Pf = Design flat roof snow load, psf.
For the purposes of this section, snow load shall be assumed uniform on the horizontal projection without including the effects of drift or sliding. The Importance Factor, Is, used in calculating Pf may be considered 1.0 for use in the formula for Ws."
Utah Code § 15A-3-107