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Wind Load Report

1. Site & Building Data

Roof Type: Gable  
Wind Speed (ult): 115 mph
Exposure Category: B  
Enclosure Class: Enclosed  
Building Width (W): 20 ft.
Building Length (L): 40 ft.
Eave Height (he): 10 ft.
Foundation Height (hf): 0 ft.
Roof Pitch: 10 /12
Eave Overhang (OHe): 1 ft.
Gable Overhang (OHg): 1 ft.

2. Parameters & Coefficients

Topographic Factor (Kzt): 1.0
Directionality Factor (Kd): .85
Roof Angle (θ): 39.81 deg.
Mean Roof Height (h): 14.17 ft.
Ridge Height (hr): 18.33 ft.
Pos. Internal Pressure (+GCpi): +0.18  
Neg. Internal Pressure (-GCpi): -0.18  
Velocity Pressure Exp. Coeff. (Kh): 0.70 @ z=h
Velocity Pressure (qh): 20.16 psf
End Zone Width (a): 3.00 ft.
Zone 2/2E Dist.: 10.00 ft.

3. Design Assumptions and Notes

Code Standard: ASCE 7-10
Geometry: Regular-Shaped Bldg.
Height Class: Low-Rise Building
Notes:

4. Design Loads

Top Chord Dead Load: 7 psf
Bottom Chord Dead Load: 5 psf
Truss/Rafter Spacing: 16 in. o/c

4. Design Wind Pressures: MWFRS Envelope Procedure


Load Case A: Transverse Direction
Surface GCpf Design Pressure (psf)
(w/ +GCpi) (w/ -GCpi)
1 0.56 7.66 14.92
2 0.21 0.60 7.86
3 -0.43 -12.30 -5.04
4 -0.37 -11.09 -3.83
1E 0.69 10.28 17.54
2E 0.27 1.81 9.07
3E -0.53 -14.31 -7.06
4E -0.48 -13.31 -6.05
2OH 0.21 4.23
2EOH 0.27 5.44
3OH -0.43 -8.67
3EOH -0.53 -10.69
2OH+W 0.21/-0.7 -9.88
2EOH+W 0.27/-0.7 -8.67
a) (+) and (-) signs signify wind pressures acting toward & away from surfaces.
b) External Pressure Coefficients linearly interpolated from Fig. 28.4-1 ASCE 7-10.
c) Design building for all wind directions, 4 load patterns per load case.
d) Total horizontal shear shall not be less than that by neglecting roof wind forces.
e) Min. wind load for enclosed or partially enclosed bldg.: 16 psf wall, 8 psf roof.
f) Design pressures are for strength design, multiply by 0.6 for ASD.
Wind Loads 45 Thurston Ave
Norman J Abraham, P.E. NJA Engineering
941 New Road
ph. 7165721140    www.website.com 		-
1/8/2025 1
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Load Case B: Longitudinal Direction
Surface GCpf Design Pressure (psf)
(w/ +GCpi) (w/ -GCpi)
1 -0.45 -12.70 -5.44
2 -0.69 -17.54 -10.28
3 -0.37 -11.09 -3.83
4 -0.45 -12.70 -5.44
5 0.40 4.44 11.69
6 -0.29 -9.48 -2.22
1E -0.48 -13.31 -6.05
2E -1.07 -25.20 -17.94
3E -0.53 -14.31 -7.06
4E -0.48 -13.31 -6.05
5E 0.61 8.67 15.93
6E -0.43 -12.30 -5.04
2OH -0.69 -13.91
2EOH -1.07 -21.57
3OH -0.37 -7.46
3EOH -0.53 -10.69
2EOH+W -1.07/-0.7 -35.69
3EOH+W -0.53/-0.7 -24.80
a) (+) and (-) signs signify wind pressures acting toward & away from surfaces.
b) External Pressure Coefficients linearly interpolated from Fig. 28.4-1 ASCE 7-10.
c) Design building for all wind directions, 4 load patterns per load case.
d) Total horizontal shear shall not be less than that by neglecting roof wind forces.
e) Min. wind load for enclosed or partially enclosed bldg.: 16 psf wall, 8 psf roof.
f) Design pressures are for strength design, multiply by 0.6 for ASD.


Torsional Load Cases
Surface Load Case GCpf Design Pressure (psf)
(w/ +GCpi) (w/ -GCpi)
1T A - 1.92 3.73
2T A - 0.15 1.97
3T A - -3.07 -1.26
4T A - -2.77 -0.96
5T B - 1.11 2.92
6T B - -2.37 -0.55
a) (+) and (-) signs signify wind pressures acting toward & away from surfaces.
b) Pressures designated with a "T" are 25% of full design wind pressures.
c) Torsional loading shall apply to all 8 load patterns using the figures shown.
d) Design pressures are for strength design, multiply by 0.6 for ASD.
e) Torsional Design Exceptions: One story bldg. with h ≤ 30 ft,
   Two stories or less framed with light frame construction,
   Two stories or less with flexible diaphragms.
Wind Loads 45 Thurston Ave
Norman J Abraham, P.E. NJA Engineering
941 New Road
ph. 7165721140    www.website.com 		-
1/8/2025 2
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5. Wind Load Calculations


1.) Lateral Loads - Transverse Direction:


Lateral Loads on Roof Diaphragm with Positive Internal Pressure
40 ft.
6.00 ft.
34.00 ft.
39.9 plf
33.3 plf
30.8 plf
23.0 plf
2664 lbs
2481 lbs
71.6 plf
61.5 plf
-9.1 plf
-3.0 plf
-27.2 plf
-21.2 plf
4.3 plf
4.9 plf
53.4 plf
43.3 plf
5.3 plf
4.3 plf
1 ft.
1 ft.
a) (-) signs signify wind lateral forces acting opposite to the direction of the arrows shown.
b) Strength design values multiplied by 0.6 to obtain ASD values.



Wind Base Shear (ASD)
Load Case A: Transverse Direction
Load Case Walls (lbs) Roof (lbs) Roof Overhangs (lbs) Total Lateral Load (lbs) R1 (lbs) R2 (lbs)
Positive Internal Pressure 2337 2677 131 5146 2664 2481
Negative Internal Pressure 2337 2677 131 5146 2664 2481
Roof Pressure = 0 2337 0 0 2337 1206 1132
Min. Pressures (8 psf, 16 psf) 1920 1600 248 3768 1884 1884
a) Bottom half of wall neglected in tributary area calculations.
b) Strength design values multiplied by 0.6 to obtain ASD values.
Wind Loads 45 Thurston Ave
Norman J Abraham, P.E. NJA Engineering
941 New Road
ph. 7165721140    www.website.com 		-
1/8/2025 3
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2.) Lateral Loads - Longitudinal Direction:


Lateral Loads on Roof Diaphragm with Positive Internal Pressure
20 ft.
3.00 ft.
17.00 ft.
36.9 plf
28.4 plf
26.0 plf
13.3 plf
47.2 lbs
146.1 lbs
170.4 lbs
347.8 lbs
838 lbs
771 lbs
a) (-) signs signify wind lateral forces acting opposite to the direction of the arrows shown.
b) Strength design values multiplied by 0.6 to obtain ASD values.
c) Where the length of building (L) exceeds 4X the mean roof height (h), wind drag forces should additionally be considered.



Wind Base Shear (ASD)
Load Case B: Longitudinal Direction
Load Case Walls (lbs) Gable Ends (lbs) Roof (lbs) Total Lateral Load (lbs) RA (lbs) RB (lbs)
Positive Internal Pressure 898 711 0 1610 838 771
Negative Internal Pressure 898 711 0 1610 838 771
Roof Pressure = 0 898 711 0 1610 838 771
Min. Pressures (8 psf, 16 psf) 960 800 0 1760 880 880
a) Bottom half of wall neglected in tributary area calculations.
b) Strength design values multiplied by 0.6 to obtain ASD values.
Wind Loads 45 Thurston Ave
Norman J Abraham, P.E. NJA Engineering
941 New Road
ph. 7165721140    www.website.com 		-
1/8/2025 4
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3.) Roof Truss Reactions:


Roof Truss/Rafter Reactions: Transverse End Zone
-96 lbs
-29 lbs
Max. Horz. ① = 109 lbs
Max. Uplift ① = 77 lbs
a) Strength design values multiplied by 0.6 to obtain ASD values.
b) Windward loads may be positive or negative depending on pitch of roof.



Roof Truss/Rafter Reactions (ASD)
w/ Positive Internal Pressure
Load Case Horizontal Load (lbs) Gross Uplift (lbs) Net Uplift (lbs) U1 (lbs) U2 (lbs)
Transverse Int. Zone -85 108 -132 -91 -41
Transverse End Zone -109 115 -125 -96 -29
Longitudinal Int. Zone 47 246 6 18 -13
Longitudinal End Zone 80 342 102 77 24
a) Gross Uplift calculations do not include any counteracting roof dead loads.
b) Net Uplift calculations include counteracting roof dead loads multiplied by 0.6 per load case (7) ASCE 7-10.
c) Strength design values multiplied by 0.6 to obtain ASD values for wind loads.
d) Loads based on truss spacing calculated at 16" o/c.
e) Negative values for horizontal load indicate load acting in windward direction (tranverse load cases).
f) Negative values for uplift indicate net downward force (zero uplift).













*Disclaimer: The calculations produced herein are for initial design and estimating purposes only. The calculations and drawings presented do not constitute a fully engineered design. All of the potential load cases required to fully design an actual structure may not be provided by this calculator. For the design of an actual structure, a registered and licensed professional should be consulted as per IRC 2012 Sec. R802.10.2 and designed according to the minimum requirements of ASCE 7-10. The wind load calculations provided by this online tool are for educational and illustrative purposes only. Medeek Design assumes no liability or loss for any designs presented and does not guarantee fitness for use.
Wind Loads 45 Thurston Ave
Norman J Abraham, P.E. NJA Engineering
941 New Road
ph. 7165721140    www.website.com 		-
1/8/2025 5