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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

  1. 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
  2. Enclosed or partially enclosed building. Calculator is not applicable for open buildings
  3. Gable roof is symmetrical. For flat roofs (θ = 0 degrees) use either Gable (G) or Monoslope (M) for "Roof Type"
  4. 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.

Snippet from ASCE 7-22 page 296


Snippet from ASCE 7-22 page 297