Worked examples - Wind webinar to AS1170.2 - ClearCalcs

Created with ClearCalcs.comWind Loads (AS1170.2) (version 19)
Client: Date: Apr 7, 2020
Author: Efficient Engineer Job #:
Project: Wind Example Project Subject: Webinar Example 1
References: AS 1170.2:2011 (Amdt 5)
Design Regional Wind Speed
AS4055 Wind Class Equivalent N2.5
Wind Loads for Load Linking
Surface Label Max Ultimate Wind ( ) Min Ultimate Wind ( ) Max Service Wind ( ) Min Service Wind ( )
Wall - Any Direction 0.587 -0.381 0.403 -0.262
Roof - Any Direction 0.369 -0.575 0.253 -0.395
Wall - Front 0.587 -0.381 0.403 -0.262
Wall - Right 0.535 -0.381 0.367 -0.262
Wall - Back 0.499 -0.381 0.343 -0.262
Wall - Left 0.465 -0.381 0.32 -0.262
Roof - Front 0.34 -0.528 0.234 -0.363
Roof - Right 0.26 -0.575 0.178 -0.395
Roof - Back 0.289 -0.528 0.199 -0.363
Roof - Left 0.369 -0.575 0.253 -0.395
Cladding - Wall 0.792 -0.572 0.544 -0.393
Structure Importance Level
Design Working Life
Wind Region

V =R 45 m/s
class =AS4055
W =table
W
u,down kPa W
u,up kPa W
s,down kPa W
s,up kPa

2: Normal Structures
NCC 2019 (~50 years)
A5
Summary
Key Inputs
1

Building Directions, Dimensions, and
Compass Directions
45
b
d
Right
θ = 90°
Back
θ = 180°
Front
θ = 0
Left
θ = 270°
W
β = 270°
S
β = 180°
N
β = 0°
NW
β = 315°
SW
β = 225°
Compass Orientation of "Front" of
Building (see description)

Breadth of Building (Left to Right)
Depth of Building (Front to Back)
Average Roof Height of Building
Roof Type
Roof Pitch
Maximum Ratio of Area of Openings on
One Surface to Sum of Total Open Area
of All Other Surfaces

Surface on Which Largest Openings
Area Exists
Overall Building Permeability
Elevated Building?
Calculate Wind Load at Heights
Height for Calculations ( )
6
Minimum Ultimate Limit State
Recurrence Interval

Ultimate Limit State Recurrence Interval
Serviceability Limit State Recurrence
Interval

β =θ=0 10 deg
b = 14 m
d = 10 m
h = 6 m
Gable/Monoslope
α = 30 deg
(A /ΣA ) =o o max 0.5
Front

Permeable: Openings in any surface > 0.5% of area
No
z =table
z m
R =min 500 years
R = 500 years
R =serv 25 years
Parameters for Special Buildings
2

Lowest Terrain Category
Smallest Number of Shielding Buildings
within a 45° Arc and 20*h Radius

Shortest Average Height of Shielding
Buildings

Smallest Average Breadth of Shielding
Buildings, Normal to Wind Stream

Highest Height of Hills, Ridges, or
Escarpments

Shortest Horizontal Upwind Distance
from Crest to a Level Half the Height
Below the Crest

Shortest Horizontal Distance from Crest
to Structure Being Designed

Surface Label Surface Type Internal Comb Factor External Comb Factor Other External Factors
Wall - Any Direction Wall - Any Direction 1 1 1
Roof - Any Direction Roof - Any Direction 1 1 1
Wall - Front Wall - Front 1 1 1
Wall - Right Wall - Right 1 1 1
Wall - Back Wall - Back 1 1 1
Wall - Left Wall - Left 1 1 1
Roof - Front Roof - Front 1 1 1
Roof - Right Roof - Right 1 1 1
Roof - Back Roof - Back 1 1 1
Roof - Left Roof - Left 1 1 1
Cladding - Wall Wall - Any Direction 1 1 1.5
Terrain Category to North
Terrain Category to Northeast
Terrain Category to East
Terrain Category to Southeast
Terrain Category to South
Terrain Category to Southwest
Terrain Category to West
Terrain Category to Northwest

TC3: Numerous closely-spaced obstructions (suburbs)
n =s 30
h =s 6 m
b =s 10 m
H = 0 m
L =u 10 m
x = 0 m

W =table
K
c,i K
c,e K K K
l p r

Terrain Properties - Worst Case of All Directions (AS 1170.2:2011, Cl 4)
Wind Loads for Linking to Other Calculators
Terrain Properties - For Each Direction (AS 1170.2:2011, Cl 4)
3

Shielding Buildings
Direction No. of Shielding Buildings Avg. Roof Height ( ) Avg. Breadth ( ) Avg. Spacing ( ) Shielding Parameter Shielding Multiplier
30 6 10 32 4.13 0.838
30 6 10 32 4.13 0.838
30 6 10 32 4.13 0.838
30 6 10 32 4.13 0.838
30 6 10 32 4.13 0.838
30 6 10 32 4.13 0.838
30 6 10 32 4.13 0.838
30 6 10 32 4.13 0.838
Hill Shape
Direction
Topographic
Feature
Height of Feature
( )
Horiz. Dist. Crest → Half
Height ( )
Horiz. Dist. Structure →
Crest ( )
Length Scale
Vertical ( )
Length Scale
Horizontal ( )
Hill-Shape
Multiplier
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Topographic Multiplier
Direction Hill Multiplier Lee Multiplier (NZ Only) Topographic Multiplier
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
M =s,table
n
s h
s m b
s m l
s m s M
s
N
NE
E
SE
S
SW
W
NW
M =h,table
H m L
u m x m L
1 m L
2 m M
h
N
NE
E
SE
S
SW
W
NW
M =t,table
M
h M
lee M
t
N
NE
E
SE
S
SW
W
NW
4

Site Wind Speed
Direction
Direction Multiplier Terrain/Height Multiplier Shielding Multiplier Topographic Multiplier Site Wind Speed
( )
Serviceability Site Wind Speed
( )
1 0.83 0.838 1 31.3 25.9
0.85 0.83 0.838 1 26.6 22
0.8 0.83 0.838 1 25 20.7
0.8 0.83 0.838 1 25 20.7
0.85 0.83 0.838 1 26.6 22
0.9 0.83 0.838 1 28.1 23.3
1 0.83 0.838 1 31.3 25.9
0.95 0.83 0.838 1 29.7 24.6
Design Wind Speeds
Building Plan
Face
Orientation
( )
Plan Cardinal Direction
( )
Wind at 45° to Left
( )
Wind within Central 90°
( )
Wind at 45° to Right
( )
Design Wind Speed
( )
0 10 30.1 31.3 26.2 31.3
90 100 26.2 25 25.4 26.2
180 190 25.4 26.6 28.8 28.8
270 280 28.8 31.3 30.1 31.3
Serviceability Wind Speeds
Building Plan
Face
Orientation
( )
Plan Cardinal
Direction ( )
( )
( )
( )
Service Wind Speed
( )
0 10 24.9 25.9 21.7 25.9
90 100 21.7 20.7 21 21.7
180 190 21 22 23.9 23.9
270 280 23.9 25.9 24.9 25.9
Area of Openings in Surfaces
Building Surface Area of Openings ( )
0
0
0
0
0
0
0
0
One Surface to the Sum of Total
Openings on Other Surfaces

V =sit,β
M
d M
z,cat M
s M
t
V
sit,β
m/s V
sit,β,serv m/s
N
NE
E
SE
S
SW
W
NW
V =des,θ,table
θ
deg β deg V
sit,θ−45 m/s V
sit,θ m/s V
sit,θ+45 m/s V
des,θ m/s
Front
Right
Back
Left
V =des,θ,serv,table
θ
deg β deg V
sit,θ−45,serv m/s V
sit,θ,serv m/s V
sit,θ+45,serv m/s V
des,θ,serv m/s
Front
Right
Back
Left

A =o
A
o m2
Front
Right
Back
Left
Roof − FrontSide
Roof − RightSide
Roof − BackSide
Roof − LeftSide
A =o,ratio,max 0.5
Site & Design Wind Speed (AS 1170.2:2011, Cl 2.2-2.3)
Design Internal Wind Pressure (AS 1170.2:2011, Cl 2.4)
5

Internal Pressure Coefficients
Windward Face Internal Pressure #1 Internal Pressure #2
Front -0.3 0
Right -0.3 0
Back -0.3 0
Left -0.3 0
Design Internal Wind Pressure
Windward Face Dynamic Shape Factor Design Wind Speed ( ) Design Int Wind #1 ( ) Design Int Wind #2 ( )
Front 1 31.3 -0.176 0
Right 1 26.2 -0.124 0
Back 1 28.8 -0.15 0
Left 1 31.3 -0.176 0
Minimum Design Internal Wind Pressure
Maximum Design Internal Wind
Pressure

Serviceability Internal Wind Pressure
Windward Face Dynamic Shape Factor Service Wind Speed ( ) Service Int Wind #1 ( ) Service Int Wind #2 ( )
Front 1 25.9 -0.121 0
Right 1 21.7 -0.0851 0
Back 1 23.9 -0.103 0
Left 1 25.9 -0.121 0
Minimum Serviceability Internal Wind
Pressure

Maximum Serviceability Internal Wind
Pressure

External Pressure Coefficient -
Windward Wall

External Pressure Coefficient - Leeward
Wall (front/back of building)

Wall (left/right of building)

Maximum Side Wall

External Pressure Coefficients on Walls
Windward Face Front External Pressure Left External Pressure Back External Pressure Right External Pressure
Front 0.7 -0.65 -0.5 -0.65
Right -0.65 -0.557 -0.65 0.7
Back -0.5 -0.65 0.7 -0.65
Left -0.65 0.7 -0.65 -0.557
Design External Wind Pressure for Walls
Windward
Wall
Dynamic Shape
Factor
Design Wind
Speed ( )
Design Front External Wind
Pressure ( )
Design Right External Wind
Pressure ( )
Design Back External Wind
Pressure ( )
Design Left External Wind
Pressure ( )
Front 1 31.3 0.411 -0.381 -0.293 -0.381
Right 1 26.2 -0.268 -0.23 -0.268 0.289
Back 1 28.8 -0.25 -0.324 0.349 -0.324
Left 1 31.3 -0.381 0.411 -0.381 -0.327
C =pi,table
C
pi,1 C
pi,2
p =i,table
C
dyn V
des,θ m/s p
i,1 kPa p
i,2 kPa
p =i,1 −0.176 kPa
p =i,2 0 kPa
p =i,serv,table
C
dyn V
des,θ m/s p
i,serv,1 kPa p
i,serv,2 kPa
p =i,serv,1 −0.121 kPa
p =i,serv,2 0 kPa

C =pe,W 0.7
C =pe,fb,L −0.5
C =pe,lr,L −0.557
C =pe,S −0.65
C =pe,table
C
pe,Front C
pe,Left C
pe,Back C
pe,Right
p =e,table
C
dyn V
des,θ m/s p
e,Front kPa p
e,Right kPa p
e,Back kPa p
e,Left kPa
Design External Wind Pressure on Walls (AS 1170.2:2011, Cl 2.4)
6

Design External Wind Pressures on Each
Wall
Surface Minimum External Pressure ( ) Maximum External Pressure ( )
Front -0.381 0.411
Right -0.381 0.411
Back -0.381 0.349
Left -0.381 0.289
Minimum Design External Wind
Pressure on All Walls

Maximum Design External Wind

Windward
Wall
Dynamic Shape
Factor
Design Wind
Speed
( )
Pressure ( )
Pressure ( )
Pressure ( )
Pressure ( )
Front 1 25.9 0.282 -0.262 -0.202 -0.262
Right 1 21.7 -0.184 -0.158 -0.184 0.199
Back 1 23.9 -0.171 -0.223 0.24 -0.223
Left 1 25.9 -0.262 0.282 -0.262 -0.225
Serviceability External Wind Pressures
on Each Wall
Front -0.262 0.282
Right -0.262 0.282
Back -0.262 0.24
Left -0.262 0.199
Minimum Serviceability External Wind

Maximum Serviceability External Wind

External Pressure Coefficients on Roof
Windward
Wall
Front Pressure
#1
Front Pressure
#2
Right Pressure
#1
Right Pressure
#2
Back Pressure #1 Back Pressure #2 Left Pressure #1 Left Pressure #2
Front -0.22 0.28 -0.98 -0.44 -0.6 -0.6 -0.98 -0.44
Right -0.9 -0.4 -0.2 0.329 -0.9 -0.4 -0.6 -0.6
Back -0.6 -0.6 -0.98 -0.44 -0.22 0.28 -0.98 -0.44
Left -0.9 -0.4 -0.6 -0.6 -0.9 -0.4 -0.2 0.329
Design External Pressures on Roof
Windward
Wall
Front Pressure
#1 ( )
Front Pressure
#2 ( )
Right Pressure #1
( )
Right Pressure
#2 ( )
Back Pressure #1
( )
Back Pressure #2
( )
Left Pressure #1
( )
Left Pressure #2
( )
Front -0.129 0.164 -0.575 -0.258 -0.352 -0.352 -0.575 -0.258
Right -0.372 -0.165 -0.0826 0.136 -0.372 -0.165 -0.248 -0.248
Back -0.299 -0.299 -0.489 -0.22 -0.11 0.14 -0.489 -0.22
Left -0.528 -0.235 -0.352 -0.352 -0.528 -0.235 -0.117 0.193
p =e,walls
p
e,min kPa p
e,max kPa
p =e,walls,1 −0.381 kPa
p =e,walls,2 0.411 kPa
p =e,serv,table
C
dyn
V
des,θ
m/s
p
e,serv,Front kPa p
e,serv,Right kPa p
e,serv,Back kPa p
e,serv,Left kPa
p =e,serv,walls
p
e,serv,min kPa p
e,serv,max kPa
p =e,walls,serv,1 −0.262 kPa
p =e,walls,serv,2 0.282 kPa

C =pe,roof,table
C
pe,rF,1 C
pe,rF,2 C
pe,rR,1 C
pe,rR,2 C
pe,rB,1 C
pe,rB,2 C
pe,rL,1 C
pe,rL,2
p =e,roof,table
p
e,rF,1 kPa p
e,rF,2 kPa p
e,rR,1 kPa p
e,rR,2 kPa p
e,rB,1 kPa p
e,rB,2 kPa p
e,rL,1 kPa p
e,rL,2 kPa
Design External Wind Pressure on Roof (AS 1170.2:2011, Cl 2.4)
7

Side of the Roof
Side of Roof Minimum External Pressure ( ) Maximum External Pressure ( )
Front -0.528 0.164
Right -0.575 0.136
Back -0.528 0.14
Left -0.575 0.193
Pressure on Entire Roof


Windward
Wall
Front Pressure
#1
( )
Front Pressure
#2
( )
Right Pressure
#1
( )
Right Pressure
#2
( )
Back Pressure #1
( )
Back Pressure #2
( )
Left Pressure #1
( )
Left Pressure #2
( )
Front -0.0887 0.113 -0.395 -0.177 -0.242 -0.242 -0.395 -0.177
Right -0.255 -0.114 -0.0568 0.0932 -0.255 -0.114 -0.17 -0.17
Back -0.206 -0.206 -0.336 -0.151 -0.0754 0.096 -0.336 -0.151
Left -0.363 -0.161 -0.242 -0.242 -0.363 -0.161 -0.0806 0.132
Side of the Roof
Front -0.363 0.113
Right -0.395 0.0932
Back -0.363 0.096
Left -0.395 0.132


Frictional Drag Load Required for Wind
from Front or Back
No
from Left or Right
No
Design Frictional Drag Wind Pressure
Windward Wall Dynamic Shape Factor Coefficient Area Reduction Factor Design Wind Speed ( ) Side Frictional Drag Pressure ( )
Front 1 0 0 31.3 0
Right 1 0 0 26.2 0
Back 1 0 0 28.8 0
Left 1 0 0 31.3 0
Comments
p =e,roof
p
e,min kPa p
e,max kPa
p =e,roof,1 −0.575 kPa
p =e,roof,2 0.193 kPa
p =e,roof,serv,table
p
e,rF,serv,1
kPa
p
e,rF,serv,2
kPa
p
e,rR,serv,1
kPa
p
e,rR,serv,2
kPa
p
e,rB,serv,1 kPa p
e,rB,serv,2 kPa p
e,rL,serv,1 kPa p
e,rL,serv,2 kPa
p =e,roof,serv
p
e,serv,min kPa p
e,serv,max kPa
p =e,roof,serv,1 −0.395 kPa
p =e,roof,serv,2 0.132 kPa

C =f,fb,flag
C =f,lr,flag
f =table
C
dyn C
f K
a V
des,θ m/s f kPa

Design Frictional Drag (AS 1170.2:2011, Cl 5.5)
Comments
8

Created with ClearCalcs.comWind Loads (AS1170.2) (version 19)
Client: Date: Apr 7, 2020
Author: Efficient Engineer Job #:
Project: Wind Example Project #2 Subject: QLD Wind Example #2
References: AS 1170.2:2011 (Amdt 5)
Design Regional Wind Speed
AS4055 Wind Class Equivalent C2.6
Surface Label Max Ultimate Wind ( ) Min Ultimate Wind ( ) Max Service Wind ( ) Min Service Wind ( )
Wall - Any Direction 3.77 -3.08 1.7 -1.39
Roof - Any Direction 1.48 -3.11 0.666 -1.4
Wall - Front 0.541 -3.08 0.244 -1.39
Wall - Right 3.1 -0.53 1.4 -0.239
Wall - Back 2 -1.21 0.901 -0.547
Wall - Left 3.05 0.14 1.37 0.0629
Roof - Front -2.06 -3.11 -0.931 -1.4
Roof - Right 0.808 -0.251 0.364 -0.113
Roof - Back -0.0235 -0.835 -0.0106 -0.376
Roof - Left 1.28 0.0634 0.577 0.0286
Structure Importance Level
Design Working Life
Wind Region

V =R 69.4 m/s
class =AS4055
W =table
W
u,down kPa W
u,up kPa W
s,down kPa W
s,up kPa

2: Normal Structures
NCC 2019 (~50 years)
C
Summary
Key Inputs
1

Building Directions, Dimensions, and
Compass Directions
45
b
d
Right
θ = 90°
Back
θ = 180°
Front
θ = 0
Left
θ = 270°
W
β = 270°
S
β = 180°
N
β = 0°
NW
β = 315°
SW
β = 225°
Compass Orientation of "Front" of
Building (see description)

Breadth of Building (Left to Right)
Depth of Building (Front to Back)
Average Roof Height of Building
Roof Type
Roof Pitch
One Surface to Sum of Total Open Area
of All Other Surfaces

Surface on Which Largest Openings
Area Exists
Overall Building Permeability
Elevated Building?
Calculate Wind Load at Heights
Height for Calculations ( )
9
Minimum Ultimate Limit State
Recurrence Interval

Ultimate Limit State Recurrence Interval
Serviceability Limit State Recurrence
Interval

β =θ=0 15 deg
b = 22 m
d = 17 m
h = 9 m
Hip
α = 15 deg
(A /ΣA ) =o o max 2
Front

Permeable: Openings in any surface > 0.5% of area
No
z =table
z m
R =min 500 years
R = 500 years
R =serv 25 years
Parameters for Special Buildings
2

Lowest Terrain Category
Smallest Number of Shielding Buildings
within a 45° Arc and 20*h Radius

Shortest Average Height of Shielding
Buildings

Smallest Average Breadth of Shielding
Buildings, Normal to Wind Stream

Highest Height of Hills, Ridges, or
Escarpments

Shortest Horizontal Upwind Distance
from Crest to a Level Half the Height
Below the Crest

Shortest Horizontal Distance from Crest
to Structure Being Designed

Surface Label Surface Type Internal Comb Factor External Comb Factor Other External Factors
Wall - Any Direction Wall - Any Direction 1 1 1
Roof - Any Direction Roof - Any Direction 1 1 1
Wall - Front Wall - Front 1 1 1
Wall - Right Wall - Right 1 1 1
Wall - Back Wall - Back 1 1 1
Wall - Left Wall - Left 1 1 1
Roof - Front Roof - Front 1 1 1
Roof - Right Roof - Right 1 1 1
Roof - Back Roof - Back 1 1 1
Roof - Left Roof - Left 1 1 1
Terrain Category to North
Terrain Category to Northeast
Terrain Category to East
Terrain Category to Southeast
Terrain Category to South
Terrain Category to Southwest
Terrain Category to West
Terrain Category to Northwest

n =s 0
h =s 9 m
b =s 20 m
H = 0 m
L =u 10 m
x = 0 m

W =table
K
c,i K
c,e K K K
l p r

TC2.5: Isolated trees or obstructions (outer suburbs)
TC2: Open terrain with scattered obstructions
(farmland)
TC2.5: Isolated trees or obstructions (outer suburbs)
Terrain Properties - Worst Case of All Directions (AS 1170.2:2011, Cl 4)
Wind Loads for Linking to Other Calculators
Terrain Properties - For Each Direction (AS 1170.2:2011, Cl 4)
3

Shielding Buildings
Direction No. of Shielding Buildings Avg. Roof Height ( ) Avg. Breadth ( ) Avg. Spacing ( ) Shielding Parameter Shielding Multiplier
0 9 20 180 13.4 1
10 9 20 54 4.02 1
30 9 20 48 3.58 0.819
30 9 20 48 3.58 0.819
30 9 20 48 3.58 0.819
10 9 20 54 4.02 0.834
0 9 20 180 13.4 1
0 9 20 180 13.4 1
Hill Shape
Direction
Topographic
Feature
Height of Feature
( )
Horiz. Dist. Crest → Half
Height ( )
Horiz. Dist. Structure →
Crest ( )
Length Scale
Vertical ( )
Length Scale
Horizontal ( )
Hill-Shape
Multiplier
Hill/Ridge 120 200 400 72 576 1.13
Hill/Ridge 185 200 1 000 74 592 0.561
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 0 10 0 3.6 28.8 1
Hill/Ridge 50 400 600 144 1 150 1.04
Topographic Multiplier
Direction Hill Multiplier Lee Multiplier (NZ Only) Topographic Multiplier
1.13 1 1.13
0.561 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1 1 1
1.04 1 1.04
M =s,table
n
s h
s m b
s m l
s m s M
s
N
NE
E
SE
S
SW
W
NW
M =h,table
H m L
u m x m L
1 m L
2 m M
h
N
NE
E
SE
S
SW
W
NW
M =t,table
M
h M
lee M
t
N
NE
E
SE
S
SW
W
NW
4

Site Wind Speed
Direction
Direction Multiplier Terrain/Height Multiplier Shielding Multiplier Topographic Multiplier Site Wind Speed
( )
Serviceability Site Wind Speed
( )
1 0.83 1 1.13 65.1 43.7
1 0.83 1 1 57.6 38.7
1 0.83 0.819 1 47.2 31.7
1 0.83 0.819 1 47.2 31.7
1 0.83 0.819 1 47.2 31.7
1 0.906 0.834 1 52.5 35.2
1 0.982 1 1 68.2 45.8
1 0.906 1 1.04 65.7 44.1
Design Wind Speeds
Building Plan
Face
Orientation
( )
Plan Cardinal Direction
( )
( )
( )
( )
Design Wind Speed
( )
0 15 65.5 65.1 54.2 65.5
90 105 54.2 47.2 47.2 54.2
180 195 47.2 47.2 57.7 57.7
270 285 57.7 68.2 65.5 68.2
Serviceability Wind Speeds
Building Plan
Face
Orientation
( )
Plan Cardinal
Direction ( )
( )
( )
( )
Service Wind Speed
( )
0 15 44 43.7 36.4 44
90 105 36.4 31.7 31.7 36.4
180 195 31.7 31.7 38.8 38.8
270 285 38.8 45.8 44 45.8
Large, Permanently-Open Ventilators
Present per Cl 5.3.1.3?
Area of Openings in Surfaces
Building Surface Area of Openings ( )
0
0
0
0
0
0
0
0
One Surface to the Sum of Total
Openings on Other Surfaces

V =sit,β
M
d M
z,cat M
s M
t
V
sit,β
m/s V
sit,β,serv m/s
N
NE
E
SE
S
SW
W
NW
V =des,θ,table
θ
deg β deg V
sit,θ−45 m/s V
sit,θ m/s V
sit,θ+45 m/s V
des,θ m/s
Front
Right
Back
Left
V =des,θ,serv,table
θ
deg β deg V
sit,θ−45,serv m/s V
sit,θ,serv m/s V
sit,θ+45,serv m/s V
des,θ,serv m/s
Front
Right
Back
Left

No
A =o
A
o m2
Front
Right
Back
Left
Roof − FrontSide
Roof − RightSide
Roof − BackSide
Roof − LeftSide
A =o,ratio,max 2
Site & Design Wind Speed (AS 1170.2:2011, Cl 2.2-2.3)
Design Internal Wind Pressure (AS 1170.2:2011, Cl 2.4)
5

Internal Pressure Coefficients
Windward Face Internal Pressure #1 Internal Pressure #2
Front 0.49 0.49
Right -0.65 -0.65
Back -0.3 -0.3
Left -0.65 -0.65
Design Internal Wind Pressure
Windward Face Dynamic Shape Factor Design Wind Speed ( ) Design Int Wind #1 ( ) Design Int Wind #2 ( )
Front 1 65.5 1.26 1.26
Right 1 54.2 -1.14 -1.14
Back 1 57.7 -0.6 -0.6
Left 1 68.2 -1.81 -1.81
Minimum Design Internal Wind Pressure
Maximum Design Internal Wind
Pressure

Serviceability Internal Wind Pressure
Windward Face Dynamic Shape Factor Service Wind Speed ( ) Service Int Wind #1 ( ) Service Int Wind #2 ( )
Front 1 44 0.569 0.569
Right 1 36.4 -0.516 -0.516
Back 1 38.8 -0.27 -0.27
Left 1 45.8 -0.817 -0.817
Minimum Serviceability Internal Wind
Pressure

Maximum Serviceability Internal Wind
Pressure

Windward Wall

Wall (front/back of building)

Wall (left/right of building)

Maximum Side Wall

External Pressure Coefficients on Walls
Windward Face Front External Pressure Left External Pressure Back External Pressure Right External Pressure
Front 0.7 -0.65 -0.3 -0.65
Right -0.65 -0.545 -0.65 0.7
Back -0.3 -0.65 0.7 -0.65
Left -0.65 0.7 -0.65 -0.545
Windward
Wall
Dynamic Shape
Factor
Design Wind
Speed ( )
Pressure ( )
Pressure ( )
Pressure ( )
Pressure ( )
Front 1 65.5 1.8 -1.67 -0.773 -1.67
Right 1 54.2 -1.14 -0.96 -1.14 1.23
Back 1 57.7 -0.6 -1.3 1.4 -1.3
Left 1 68.2 -1.81 1.95 -1.81 -1.52
C =pi,table
C
pi,1 C
pi,2
p =i,table
C
dyn V
des,θ m/s p
i,1 kPa p
i,2 kPa
p =i,1 −1.81 kPa
p =i,2 1.26 kPa
p =i,serv,table
C
dyn V
des,θ m/s p
i,serv,1 kPa p
i,serv,2 kPa
p =i,serv,1 −0.817 kPa
p =i,serv,2 0.569 kPa

C =pe,W 0.7
C =pe,fb,L −0.3
C =pe,lr,L −0.545
C =pe,S −0.65
C =pe,table
C
pe,Front C
pe,Left C
pe,Back C
pe,Right
p =e,table
C
dyn V
des,θ m/s p
e,Front kPa p
e,Right kPa p
e,Back kPa p
e,Left kPa
Design External Wind Pressure on Walls (AS 1170.2:2011, Cl 2.4)
6

Wall
Front -1.81 1.8
Right -1.67 1.95
Back -1.81 1.4
Left -1.67 1.23


Windward
Wall
Dynamic Shape
Factor
Design Wind
Speed
( )
Pressure ( )
Pressure ( )
Pressure ( )
Pressure ( )
Front 1 44 0.813 -0.755 -0.348 -0.755
Right 1 36.4 -0.516 -0.433 -0.516 0.555
Back 1 38.8 -0.27 -0.586 0.631 -0.586
Left 1 45.8 -0.817 0.88 -0.817 -0.686
Serviceability External Wind Pressures
on Each Wall
Front -0.817 0.813
Right -0.755 0.88
Back -0.817 0.631
Left -0.755 0.555


External Pressure Coefficients on Roof
Windward
Wall
Front Pressure
#1
Front Pressure
#2
Right Pressure
#1
Right Pressure
#2
Back Pressure #1 Back Pressure #2 Left Pressure #1 Left Pressure #2
Front -0.718 -0.312 -0.506 -0.506 -0.506 -0.506 -0.506 -0.506
Right -0.5 -0.5 -0.627 -0.191 -0.5 -0.5 -0.5 -0.5
Back -0.506 -0.506 -0.506 -0.506 -0.718 -0.312 -0.506 -0.506
Left -0.5 -0.5 -0.5 -0.5 -0.5 -0.5 -0.627 -0.191
Windward
Wall
Front Pressure
#1 ( )
Front Pressure
#2 ( )
Right Pressure
#1 ( )
Right Pressure
#2 ( )
Back Pressure #1
( )
Back Pressure #2
( )
Left Pressure #1
( )
Left Pressure #2
( )
Front -1.85 -0.803 -1.3 -1.3 -1.3 -1.3 -1.3 -1.3
Right -0.88 -0.88 -1.1 -0.336 -0.88 -0.88 -0.88 -0.88
Back -1.01 -1.01 -1.01 -1.01 -1.43 -0.623 -1.01 -1.01
Left -1.4 -1.4 -1.4 -1.4 -1.4 -1.4 -1.75 -0.533
p =e,walls
p
e,min kPa p
e,max kPa
p =e,walls,1 −1.81 kPa
p =e,walls,2 1.95 kPa
p =e,serv,table
C
dyn
V
des,θ
m/s
p
e,serv,Front kPa p
e,serv,Right kPa p
e,serv,Back kPa p
e,serv,Left kPa
p =e,serv,walls
p
e,serv,min kPa p
e,serv,max kPa
p =e,walls,serv,1 −0.817 kPa
p =e,walls,serv,2 0.88 kPa

C =pe,roof,table
C
pe,rF,1 C
pe,rF,2 C
pe,rR,1 C
pe,rR,2 C
pe,rB,1 C
pe,rB,2 C
pe,rL,1 C
pe,rL,2
p =e,roof,table
p
e,rF,1 kPa p
e,rF,2 kPa p
e,rR,1 kPa pe,rR,2 kPa p
e,rB,1 kPa p
e,rB,2 kPa p
e,rL,1 kPa p
e,rL,2 kPa
Design External Wind Pressure on Roof (AS 1170.2:2011, Cl 2.4)
7

Side of the Roof
Front -1.85 -0.803
Right -1.4 -0.336
Back -1.43 -0.623
Left -1.75 -0.533


Windward
Wall
Front Pressure
#1
( )
Front Pressure
#2
( )
Right Pressure
#1
( )
Right Pressure
#2
( )
Back Pressure #1
( )
Back Pressure #2
( )
Left Pressure #1
( )
Left Pressure #2
( )
Front -0.833 -0.362 -0.587 -0.587 -0.587 -0.587 -0.587 -0.587
Right -0.397 -0.397 -0.498 -0.151 -0.397 -0.397 -0.397 -0.397
Back -0.456 -0.456 -0.456 -0.456 -0.647 -0.281 -0.456 -0.456
Left -0.629 -0.629 -0.629 -0.629 -0.629 -0.629 -0.789 -0.24
Side of the Roof
Front -0.833 -0.362
Right -0.629 -0.151
Back -0.647 -0.281
Left -0.789 -0.24


from Front or Back
No
from Left or Right
No
Design Frictional Drag Wind Pressure
Windward Wall Dynamic Shape Factor Coefficient Area Reduction Factor Design Wind Speed ( ) Side Frictional Drag Pressure ( )
Front 1 0 0 65.5 0
Right 1 0 0 54.2 0
Back 1 0 0 57.7 0
Left 1 0 0 68.2 0
Comments
p =e,roof
p
e,min kPa p
e,max kPa
p =e,roof,serv,table
p
e,rF,serv,1
kPa
p
e,rF,serv,2
kPa
p
e,rR,serv,1
kPa
p
e,rR,serv,2
kPa
p
e,rB,serv,1 kPa p
e,rB,serv,2 kPa p
e,rL,serv,1 kPa p
e,rL,serv,2 kPa
p =e,roof,serv
p
e,serv,min kPa p
e,serv,max kPa

C =f,fb,flag
C =f,lr,flag
f =table
C
dyn C
f K
a V
des,θ m/s f kPa

Design Frictional Drag (AS 1170.2:2011, Cl 5.5)
Comments
8

Worked examples - Wind webinar to AS1170.2 - ClearCalcs

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