This sub-page determines wind load of the roof for buildings of any height as per ASCE 7-10 Chapter 30 Part 2. Wind loads are determined for the roof from wind in any direction.
Assumptions
- Mean roof heights, h ≤ 500 ft (= 150 meters)
- Major structural components supporting tributary areas > 700 ft^2 shall be permitted to be designed using the provisions for main wind force resisting systems (MWFRS)
- Effective area, Ae for a component or cladding panel is:
a. Ae = span length x effective width > 1/3 span length
b. Ae = h^2 / 3 for a vertically spanning concrete masonry unit (CMU) or concrete wall
- Enclosed, partially enclosed and partially open buildings. Calculator is not applicable for open buildings.
- Applicable for Gable roof with roof angle, θ ≤ 45 degrees, or Monoslope roof with roof angle, θ ≤ 3 degrees. For flat roofs (θ = 0 degrees) use either Gable (G) or Monoslope (M) for "Roof Type". Gable roof is symmetrical.
- Sign convention of wind pressures: + is acting toward the surface, - is acting away from the surface
⬇️ Inputs
Building properties
Building Classification
:III
Enclosed? (Y/N)
:Y
Roof Type
:Gable
Ridge Height, hr
:42ft
Eave Height, he
:42ft
Building Width, B
:222ft
Building Length, L
:204ft
Component Name
:Joist
Effective Area, Ae =
:208sqft
Overhangs? (Y/N)
:NWind and site properties
Exposure Category
:C
Wind Speed, V
:170mph
Topographic Factor, Kzt
:1
Directional Factor, Kd
:0.85
Hurricane Region?
:N
⬆️ Outputs
Building properties
Roof Angle, θ
:0.0deg
Mean Roof Height, h
:42.0ft
Width of Zone 2 (edge), a
:16.8ft
Width of Zone 3 (corner)
:16.8ft
Velocity pressure, qh
Velocity pressure coefficient, Kh
:1.05435523493483
Velocity pressure, qh (lb/ft^2)
:66.3046050462057Wind pressure coefficients
Roof external pressure coefficient, GCp
0.2 | |
-0.9 | |
-1.1 | |
-1.1 |
Internal pressure coefficient, GCpi
0.18 | |
-0.18 |
⬆️ Design wind load pressures, p
Wind load tabulation for Roof Components and Cladding. For zone definitions of gable and monoslope roofs, refer to diagrams below.
Kh | qh | ||||||
Joist | 0 | 1.05 | 66.3 | 25.2 | -71.61 | -84.87 | -84.87 |
| 15 | 1.05 | 66.3 | 25.2 | -71.61 | -84.87 | -84.87 |
| 20 | 1.05 | 66.3 | 25.2 | -71.61 | -84.87 | -84.87 |
| 25 | 1.05 | 66.3 | 25.2 | -71.61 | -84.87 | -84.87 |
| 30 | 1.05 | 66.3 | 25.2 | -71.61 | -84.87 | -84.87 |
| 35 | 1.05 | 66.3 | 25.2 | -71.61 | -84.87 | -84.87 |
| 40 | 1.05 | 66.3 | 25.2 | -71.61 | -84.87 | -84.87 |
For z = hr: | 42 | 1.05 | 66.3 | 25.2 | -71.61 | -84.87 | -84.87 |
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42 | 1.05 | 66.3 | 25.2 | -71.61 | -84.87 | -84.87 | |
42 | 1.05 | 66.3 | 25.2 | -71.61 | -84.87 | -84.87 |
The diagrams are from Figure 30.3-2A to 2D and Figure 30.3-5A to 5B of ASCE 7-22.
❗The roof zone diagrams between ASCE 7-10 and ASCE 7-22 differ. Use the ASCE 7-22 diagrams as provided below.
Gable Roof Zones for GCp
h ≤ 60 ft and θ ≤ 7°
h ≤ 60 ft and 20° ≤ θ ≤ 27°
h ≤ 60 ft and 7° ≤ θ ≤ 20°
h ≤ 60 ft and 27° ≤ θ ≤ 45°
Monoslope Roof Zones for GCp
h ≤ 60 ft and 3° ≤ θ ≤ 10°
h ≤ 60 ft and 10° < θ ≤ 30°
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