Allows up to 10 different flat roof snow loads to be calculated by entering values for all of the parameters in accordance with ASCE 7. EXAMPLE CALCULATIONS F Section 7.3.1 Table 7-2 Section 7.3.2 Table 7-3 Section 7.3.3 … Pg = ground snow load Pf = flat roof snow load = Pg*I*Ce*Ct Ps = sloped roof snow load = Pf*Cs The "minimum" Pf is defined in ASCE-7-98 as: I*Pg when Pg is less than or equal to 20psf I*20 when Pg is greater than 20psf +++++ The "minimum" that is specified is for cases when the Ce*Ct<1.00. Snow load: (ASCE 7-05, 10, IBC 2006, 2009, 2012) ... Flat roof snow load: p f = 0.7 C e C t I s p g. C e is exposure factor. Sloped Roof Snow Loads. This program specifically follows Section 7.0, Snow Loads, of the ASCE 7-10 Standard, "Minimum Design Loads for Buildings and Other Structures". The second example is a one-story L-shaped roof. Like its predecessors that accompanied earlier versions of ASCE 7, this new edition of Snow Loads discusses flat roof loads, sloped roof loads, partial loads, and all types of conventional drift loading. Allows up to 10 different sloped roof snow loads. р g = ground snow load. I = importance factor. 2. According to ASCE 7-16, the design snow loads for flat roofs and sloped roofs can be obtained using the following equations: where. If slope ≤ ½” in 12”, add rain-on-snow surcharge (Section 7.10 ASCE 7) 2 yes . Ground snow loads do not discount that actual snow loads may exceed them, only that the risk of snow-load-induced failure is reduced to an acceptably low level. Input Data. Section 7.4 of ASCE 7-16 explains how to convert flat roof snow loads into sloped roof snow loads using the roof slope factor, C s. The sloped roof snow load, also called the balanced load, is the basis for determining the snow load for all structures. Flat roof snow load — The flat roof snow load, p f, is calculated in pounds per square foot (psf) from Section 7.3 of ASCE 7 and is given by Equation 7-1: p f = 0.7C eC tI sp g 0.7 is the combined exposure reduction factor for ground-to-roof conversion for normal conditions. for Balanced Snow, Drift, and Rain-on-Snow Surcharge Loadings . Question 3: Equation 16-21 (alternative basic load combination) also uses D+L+S+E/1.4. Use our ASCE Ground Snow Loads map to easily obtain the ground snow load (Figure 7-1 of ASCE 7-10) for any location in the contiguous United States. ASCE 7 in fact clarifies that S may be the flat roof snow load or the sloped roof snow load, depending upon the slope of the roof. Where flat roof snow loads exceed 30 psf (1.44 kN/m 2), 20 percent shall be combined with seismic loads. The importance factor, also found in ASCE 7-10, takes into account the type of building for which you are calculating snow loads. Building Classification : Table 1-1, page 3: Ground Snow Load, pg: psf: Figure 7-1, pages 84-85 and Table 7-1, page 92: Length of High Roof, Lu: ft. Maps of ground snow loads in IBC and in ASCE 7 indicate a 2 percent probability of the indicated load being equaled or exceeded in any given year. About the Author Michael O'Rourke, Ph.D., P.E., is a professor in the Department of Civil and Environmental Engineering at Rensselaer Polytechnic Institute, where he teaches and pursues snow load research. ASCE 7 Table 7-3 Calculate flat roof snow load pf 0.7CeCt Is pg no Is roof flat? See Table 2.9 for importance factor values, depending on the category of the building. Snow Load - Snow loading analysis for buildings with flat or low slope roofs Snow Map - Ground snow loads map (Figure 7-1 of ASCE 7-10 Code) Program Assumptions and Limitations: 1. While this may be more intuitive for flat or even gable/hip type roofs, the determination of snow loads is increasingly more difficult for arch roofs due to complex geometry. If slope ≤ ¼” in 12”, design to prevent ponding. This program specifically follows Section 7.0, Snow Loads, of the ASCE 7-10 Standard, "Minimum Design Loads for Buildings and Other Structures". The first is a simple, one story hip roof. ASCE 7-05 Code for Buildings with Flat or Low Slope Roofs (= 5 deg. or 1 in./ft.) Flat roof snow loads of 30 psf (1.44 kN/m 2) or less and roof live loads of 30 psf (1.44 kN/m 2) or less need not be combined with seismic loads. Heat flow from poorly insulated roofs melts some of the roof snowpack. For this roof the complexity involves snow load for the roof valley area. This program assumes only snow loading analysis for buildings with a flat roof, or low slope roof <= 5 degrees. ASCE702S is a spreadsheet program written in MS-Excel for the purpose of flat roof snow loading analysis for buildings and structures per the ASCE 7-02 Code. "ASCE710S" --- ASCE 7-10 CODE SNOW LOAD ANALYSIS PROGRAM "ASCE710S" is a spreadsheet program written in MS-Excel for the purpose of flat roof snow loading analysis for buildings and structures per the ASCE 7-10 Code. The ASCE 7-16 standard requires both balanced and unbalanced snow load case scenarios for a structure's design consideration. Specifically, coefficients and related and required parameters Ground snow loads map (Figure 7-1 of ASCE 7-10 Code) Figure 7-1, pages 34-35 and Table 7-1, page 30 Table … Snow Loads for Structural Design in Montana (Revised 2004) Gregory P. Theisen Michael J. Keller Jerry E. Stephens Fred F. Videon James P. Schilke December 2004 Of ASCE 7-05 Code for buildings with flat or low slope roof < = 5 degrees ≤... ( Section 7.11, ASCE 7 ) 2 yes this procedure also found in ASCE 7-10, takes into the... 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