This sub-page determines wind load for the Main Wind-Force Resisting System (MWFRS) for low-rise buildings as per ASCE 7-10 Chapter 28. Wind loads are determined for the windward wall, leeward wall, side walls and roof.
Assumptions
Applicable for low-rise buildings i.e. mean roof height, h ≤ 60 ft (= 18 meters) and h ≤ the lesser of the building width, B or building length, L
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
Main Wind-Force Resisting System (MWFRS) for low-rise buildings
Calculation
Inputs
Building properties
Building Classification
:II
Enclosed? (Y/N)
:Y
Roof Type
:Monoslope
hr
:12.5
he
:12.5ft
B
:20ft
L
:60ft
Wind and site properties
V
:110mph
Exposure Category
:C
Kzt
:1
Kd
:0.85
Hurricane Region?
:N
Output
Building geometry
θ
:0.0deg
h
:12.5ft
a =
:3ft
Check if criteria for low-rise buildings is met:
1. Is h <= 60' ?
:Yes, O.K.
2. Is h <= Lesser of L or B?
:Yes, O.K.
Wind pressure coefficients
Internal pressure coefficient, GCpi
0.18
-0.18
Note, refer to the results table below for the external pressure coefficients.
Velocity pressure, qh
Kh =
:0.85
qh, lb/ft^2 =
:22.35
Explanation
Design wind load pressures, p
The MWFRS of buildings of low-rise buildings, shall be designed for the four wind loads cases described below. For each wind load case, each corner of the building is to be taken as the windward corner. For zone definitions of the wall and roof surfaces, refer to diagrams below.
MWFRS Wind Load for Load Case 1 (transverse)
0.4
4.92
12.96
-0.69
-19.45
-11.4
-0.37
-12.29
-4.25
-0.29
-10.5
-2.46
---
---
0.61
9.61
17.66
-1.07
-27.94
-19.89
-0.53
-15.87
-7.82
-0.43
-13.63
-5.59
MWFRS Wind Load for Load Case 2 (longitudinal)
-0.45
-14.08
-6.03
-0.69
-19.45
-11.4
-0.37
-12.29
-4.25
-0.45
-14.08
-6.03
0.4
4.92
12.96
-0.29
-10.5
-2.46
-0.48
-14.75
-6.71
-1.07
-27.94
-19.89
-0.53
-15.87
-7.82
-0.48
-14.75
-6.71
0.61
9.61
17.66
-0.43
-13.63
-5.59
*Note, use roof angle θ = 0 deg for longitudinal direction
MWFRS Wind Load for Load Case 3 (transverse, torsional)
1.23
3.24
-4.86
-2.85
-3.07
-1.06
-2.63
-0.61
MWFRS Wind Load for Load Case 4 (longitudinal, torsional)
-3.52
-1.51
-4.86
-2.85
-3.07
-1.06
-3.52
-1.51
1.23
3.24
-2.63
-0.61
The diagrams are from Figure 28.3-1 and Figure 28.3-2 of ASCE 7-22, these wind load cases are the same in ASCE 7-10.