This sub-page determines wind load for the Main Wind-Force Resisting System (MWFRS) for buildings of any height as per ASCE 7-10 Chapter 27. Wind loads are determined for the windward wall, leeward wall, side walls and roof.
Assumptions
- Mean roof heights, h ≤ 500 ft (= 150 meters)
- Enclosed or partially enclosed building. Calculator is not applicable for open buildings.
- Gable roof is symmetrical. For flat roofs (θ = 0 degrees) use either Gable (G) or Monoslope (M) for "Roof Type".
- Sign convention of wind pressures: + is acting toward the surface, - is acting away from the surface
⬇️ Inputs
Building properties
Building Classification
:II
Enclosed Building? (Y/N)
:Y
Roof Type
:Gable
Ridge Height, hr
:40ft
Eave Height, he
:25ft
Building Width, B
:30ft
Building Length, L
:40ft
Damping Ratio, β
:0.05Suggested range of β = 0.010-0.070
Period Coeficient, Ct
:0.035Suggested range of Ct = 0.020-0.035
Wind and site properties
Wind direction to building ridge
:Normal
Wind Speed, V
:130mph
Exposure Category
:B
Topographic Factor, Kzt
:1
Directional Factor, Kd
:0.85
Hurricane Region?
:N
⬆️ Outputs
Building geometry
Roof Angle, θ
:45.0deg
Mean Roof Height, h
:32.5ft
Ratio h/L
:1.08333333333333
Wind pressure coefficients
External pressure coefficient Cp, walls
0.8 | |
-0.5 | |
-0.7 |
External pressure coefficient Cp, roof
Windward Roof Cp = | 0 | |
Windward Roof Cp = | 0 | |
Leeward Roof Cp = | -0.6 | |
| | |
Internal pressure coefficient. GCpi
0.18 | |
-0.18 |
Velocity pressure, qh
Velocity pressure coefficient, Kh
:0.716797796648865
Velocity pressure, qh (lb/ft^2)
:26.359808893084
Gust Effect Factor, G
Frequency, f
:2.09903381443288HzIf f>=1, it is a rigid structure
Simplified Gust Factor, G for rigid structure
:0.85
Calculated Gust Factor, G for rigid structure
:0.86
Calculated Gust Factor, G for flexible structure
:N.A.
Chosen Gust Factor, G
:0.85
⬆️ Design wind load pressures, p
Results table below
:Normal to Ridge Wind Load Tabulation for MWFRS - Buildings of Any Height
0 | 0.57 | 21.13 | 0.8 | 9.63 | 19.12 | |
| 15 | 0.57 | 21.13 | 0.8 | 9.63 | 19.12 |
| 20 | 0.62 | 22.95 | 0.8 | 10.86 | 20.35 |
| 25 | 0.67 | 24.46 | 0.8 | 11.89 | 21.37 |
| 30 | 0.7 | 25.76 | 0.8 | 12.77 | 22.26 |
| 35 | 0.73 | 26.92 | 0.8 | 13.56 | 23.05 |
For z = hr: | 40 | 0.76 | 27.97 | 0.8 | 14.28 | 23.77 |
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25 | 0.67 | 24.46 | 0.8 | 11.89 | 21.37 | |
32.5 | 0.72 | 26.36 | 0.8 | 13.18 | 22.67 | |
-0.5 | -15.95 | -6.46 | ||||
-0.7 | -20.43 | -10.94 | ||||
Roof (windward) cond. 1 | 0 | -4.74 | 4.74 | |||
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Roof (windward) cond. 2 | - | - | - | 0 | -4.74 | 4.74 |
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Roof (leeward) | - | - | - | -0.6 | -18.19 | -8.7 |
| - | - | - | | | |
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How do I apply these results to my building?
The MWFRS of buildings of all heights, shall be designed for the wind load cases described below. The diagrams below are from Figure 27.3-8 of ASCE 7-22, these wind load cases are the same in ASCE 7-10. Note, the diagrams are plan view and roof pressures are not shown for clarity.
Notation
- Pwx, Pwy = windward face pressure acting in the X, Y principal axis, respectively
- PLx, PLy = leeward face pressure acting in the X, Y principal axis, respectively
- ex, ey = eccentricity for X, Y principal axis of the structure, respectively
- Mz = torsional moment per unit height acting about a vertical axis of the building
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