Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
WIND-RELATED ISSUES IN THE DESIGN OF BUILDINGS
Copyright© 2018 by RWDI. All rights reserved.
This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.
Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
Copyright© 2018 by RWDI. All rights reserved.
American Institute of Architects
This course provides a comprehensive review of wind related issues for high-rise buildings. Both derivation of overall structural wind loads and local wind loads for the design of cladding or building facades are discussed with emphasis placed on wind tunnel testing.
Abstract
Copyright© 2018 by RWDI. All rights reserved.
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
1. Assess general methodologies and potential limitations included in building codes and standards for the derivation of wind loads and wind effects
2. Define the aerodynamic and meteorological variables involved in wind engineering.
3. Describe the potential benefits of alternative modeling and analytical approaches for the derivation of wind loads, specifically wind tunnel testing.
4. Evaluate potential mitigation strategies of real building project examples that have faced wind-related issues
Learning Objectives
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Derek Kelly, P.Eng.
Senior Project Manager, Principal
Presented By
Derek is known for his ability to make exceptionally complex and demanding projects advance smoothly and without surprises. His keen communication skills, combined with his extensive experience in the design and construction of bridges and high-rise buildings, make him an invaluable leader on any project. Clients not only benefit from Derek’s mastery of project leadership skills from financial management to quality assurance, they enjoy the experience of collaborating with him as he steers their projects to successful conclusions.
1. Introduction to Wind Effects
2. Nature of Wind Speed• Effects of Local terrain
• Effects of Local climate
Agenda
3. Modelling the Building• Wind Load Studies
4. Influence of Shape• Structural Wind Load
Studies: Input And Output
Copyright© 2018 by RWDI. All rights reserved.
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Introduction to Wind Effects
Copyright© 2018 by RWDI. All rights reserved.
Structural failure
Aeroelastic instability
Cladding failure
Pedestrian wind comfort
Serviceability or wind induced motion
Types of Risk from Wind
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Flow Pattern and Pressure Distribution
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Complex geometry
Interference of neighbouring buildings
Upwind terrain
Dynamic excitation
Building codes lack of resolution
Copyright© 2018 by RWDI. All rights reserved.
Wind Load Assessment
Wind Tunnel Testing
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Building Geometry
Wind Tunnel Testing
LocalClimate
Structural Properties
Wind Loads
LocalTerrain
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Nature of Wind Speed
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Nature of Wind Speed
25 m/s
20 m/s
15 m/s
10 m/s
5 m/s
1 min 2 min 3 min 4 min 5 min0 min
153 m
64 m
12 m
Copyright© 2018 by RWDI. All rights reserved.
Vertical Profile of Wind Speed
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Effects ofLocal Terrain
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Surface Roughness
IncreasingRoughness
Copyright© 2018 by RWDI. All rights reserved.
Wind Tunnel Profiles
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Existing surroundings Future surroundings
Effect of Immediate Surroundings
Effects ofLocal Climate
Copyright© 2018 by RWDI. All rights reserved.
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Statistical analysis of wind conditions at a siteMost locations (Asia, North America, Western Europe) have useful data from local airports
Airports catalog:
• Location of instrumentation
• Height of anemometers or data acquisition equipment
• Averaging time of data acquisition equipment
Directionality of Local Wind Climate
Copyright© 2018 by RWDI. All rights reserved.
Directionality of Local Wind Climate
Wind Speed
(mph)
Probability (%)
Summer Winter
Calm 8.1 6.2
1-5 16.7 13.4
6-10 48.6 38.9
11-15 21.9 28.3
16-20 4.0 10.2
>20 0.7 2.9
Summer (May – October) Winter (November - April)
Jackson Hartsfield International Airport (1983 - 2013)
Copyright© 2018 by RWDI. All rights reserved.
Probability of Recurrence
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
1 10 100 1000 10000
Win
d S
pe
ed
(m
/s)
Mean Recurrence Interval (years)
Predicted Wind Speed Code Basic Wind Speed
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Probability of Recurrence
0.0
50.0
100.0
150.0
200.0
250.0
300.0
1 10 100 1000 10000
Win
d S
pe
ed
(k
m/h
)
Mean Recurrence Interval (years)Extra-Tropical Extra-Tropical + Typhoon Code Basic Wind Speed
Copyright© 2018 by RWDI. All rights reserved.
Wind Directionality
0
5
10
15
20
25
30
35
40
45
N10
20
30
40
50
60
70
80
E
100
110
120
130
140
150
160170
S190
200
210
220
230
240
250
260
W
280
290
300
310
320
330
340350
Design Winds
0
5
10
15
20
25
30
35
40
45
N10
20
30
40
50
60
70
80
E
100
110
120
130
140
150
160170
S190
200
210
220
230
240
250
260
W
280
290
300
310
320
330
340350
Design Winds
Beirut, Lebanon Taipei, Taiwan
Wind speed (m/s)
Mean Recurrence Interval of 50 years
Modelling The Building
Copyright© 2018 by RWDI. All rights reserved.
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Architect’s 3D Model
Wind Tunnel Models
RWDI’s 3D Model Physical Model
Copyright© 2018 by RWDI. All rights reserved.
Wind LoadStudies
Copyright© 2018 by RWDI. All rights reserved.
Cladding Wind Load Study
High Frequency Pressure Integration Study (HFPI)
High Frequency Force Balance Study (HFFB)
Common Types of Wind Loading
Assessment
Copyright© 2018 by RWDI. All rights reserved.
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Pressure Studies: Cladding &HFPI
Copyright© 2018 by RWDI. All rights reserved.
Wind Tunnel Model Data Acquisition
Copyright© 2018 by RWDI. All rights reserved.
In-House Software
Cladding Wind Load Study
Copyright© 2018 by RWDI. All rights reserved.
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Local peak pressures
for cladding design
Recommended even for short buildings
Typically lower than code
Cladding Wind Load Study
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Wind pressure vs wind direction
Local Pressure Coefficient
Copyright© 2018 by RWDI. All rights reserved.
Internal Pressure Considerations
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Wind Pressure Block Diagrams
Negative Pressure (psf)
Wind Pressure Block Diagrams
Copyright© 2018 by RWDI. All rights reserved.
ASCE 7 Standard
Condition Zone 4 (central zone)
Zone 5 (edge zone)
EnclosedBuilding
-32 -59
Open Condition
-43 -70
HFPI Structural Wind Load Study
Copyright© 2018 by RWDI. All rights reserved.
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
HFPI Structural Wind Loads
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Provides overall wind loads and wind-induced motion
Pros:
+ Includes higher order modes
+ Allows to include large podia
Cons:
- Requires simple geometry and sharp corners
- May take longer
HFPI Structural Wind Loads
HFFB Structural Wind Load Study
Copyright© 2018 by RWDI. All rights reserved.
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Force balance Wind tunnel model
HFFB Structural Wind Loads
Provides overall wind loads and wind-induced motion
Suitable for most geometries
Generally faster
Combines mean and dynamic wind loading
Copyright© 2018 by RWDI. All rights reserved.
HFFB Structural Wind Loads
Copyright© 2018 by RWDI. All rights reserved.
Base Wind Loads vs Wind Direction
0
5
10
15
20
25
30
35
40
45
N10
20
30
40
50
60
70
80
E
100
110
120
130
140
150
160170
S190
200
210
220
230
240
250
260
W
280
290
300
310
320
330
340350
Design Winds
Wind speed (m/s)
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Worst-Case Overall Forces
Effective Static FBF Wind Loads
Design Wind Loads
Load Combination Factors
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Aerodynamic response
Influence of the Wind Climate
Copyright© 2018 by RWDI. All rights reserved.
Influence of the Wind Climate
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Combination of response and directionality
Influence of the Wind Climate
Copyright© 2018 by RWDI. All rights reserved.
Aerodynamic
Response
Wind Climate
Model
Combination of
Response and
Directionality
Influence of the Wind Climate
Peak response aligned with less frequent winds
Peak response aligned with prevailing winds
Code Analytical methods mostly address drag loading only
Lift is larger in both cases but ratio of lift / drag less in more built-up surroundings
Copyright© 2018 by RWDI. All rights reserved.
Influence of Surroundings
Drag response
Direction of Loading
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
LIFT
Copyright© 2018 by RWDI. All rights reserved.
Influence of Surroundings
Drag response
DRAG
Copyright© 2018 by RWDI. All rights reserved.
Influence of Surroundings
Wake buffeting
-8E+07
-6E+07
-4E+07
-2E+07
0E+00
2E+07
4E+07
6E+07
Ba
se
To
rs
ion
al
Mo
me
nt
on
To
we
r C
(N
-m
)
10 60 110 160 210 260 310 360 Wind Direction (degrees)
Without Upstream Tower B With Upstream Tower B
N (0 deg.)
X
Y
WIND
Building codes are reliable for short, stiff buildings
Code might miss important dynamic effects on tall or unusual buildings
Wind Tunnel is always more accurate
Copyright© 2018 by RWDI. All rights reserved.
Wind Tunnel vs Code Structural Wind Loads
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Drag Loads include mean and dynamic component
Typical Tall Building - Drag
-4.0E+09
-2.0E+09
0.0E+00
2.0E+09
4.0E+09
Ba
se
Ov
ert
urn
ing
Mo
me
nt
(N-m
)
10 60 110 160 210 260 310 360
Wind Direction (degrees)
Mx
Wind Direction (degrees)
Ba
se O
ve
rtu
rnin
g M
om
en
t
Peak MaximumMean
Peak Minimum
DRAG
WIND
Dir
ecti
on
of
Lo
ad
ing
Plan
Copyright© 2018 by RWDI. All rights reserved.
Across-wind response where mean loads are negligible
Typical Tall Building – Lift
-4.0E+09
-2.0E+09
0.0E+00
2.0E+09
4.0E+09
Ba
se
Ov
ert
urn
ing
Mo
me
nt
(N-m
)
10 60 110 160 210 260 310 360
Wind Direction (degrees)
Mx
Wind Direction (degrees)
Ba
se O
ve
rtu
rnin
g M
om
en
t
Peak MaximumMean
Peak Minimum
Dir
ecti
on
of
Lo
ad
ing
Plan
WIND
LIFT
Copyright© 2018 by RWDI. All rights reserved.
Across-Wind Loading (Vortex Shedding)
Directions of fluctuating force
WIND
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Across-Wind Loading (Vortex Shedding)
Shedding frequency N (Hz) is given by:
b
USN
S = Strouhal number
U = wind speed
b = building width
“N” can be related to building frequencies
“S” is function of building shape
Above gives indication whether Vortex Shedding
will impact strength and/or serviceability Wind velocity
Cro
ssw
ind
Re
spo
nse
Vortex shedding
No vortex shedding
Copyright© 2018 by RWDI. All rights reserved.
Lift and Drag Spectra Comparison
0.001
0.01
0.1
1
10
0.001 0.01 0.1 1 10
fS/σ
^2
Reduced Frequency
0.001
0.01
0.1
1
10
0.001 0.01 0.1 1 10
fS/σ
^2
Reduced Frequency
Copyright© 2018 by RWDI. All rights reserved.
Benefit of Shape Optimization
-4.0E+09
-2.0E+09
0.0E+00
2.0E+09
4.0E+09
Ba
se
Ov
ert
urn
ing
Mo
me
nt
(N-m
)
10 60 110 160 210 260 310 360
Wind Direction (degrees)
Mx
Wind Direction (degrees)
Ba
se O
ve
rtu
rnin
g M
om
en
t
Peak MaximumMean
Peak Minimum
Dir
ecti
on
of
Lo
ad
ing
Plan
WIND
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Influence of Shape
Copyright© 2018 by RWDI. All rights reserved.
Across-Wind Response
UniformSection
Severe cross-windexcitation
SharpCorners
Copyright© 2018 by RWDI. All rights reserved.
Across-Wind Response
Tapering
Severe cross-windexcitation
Porosity
AerodynamicSolutions
Corner Modifications
Copyright© 2018 by RWDI. All rights reserved.
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
“We virtually designed [the tower] in a wind tunnel”
Bill Baker of Skidmore Owings & Merrill Discussing Dubai Project
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
432 Park Ave: Exploration of Openings
Initial wind tunnel model of 432 Park Avenue included a worst case baseline
432 Park Avenue with double story openings at five levels
Copyright© 2018 by RWDI. All rights reserved.
Study of Exploration of Openings
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
“Softened” corners
Sensitivity to Corner Details
Slotted Corners Chamfered Corners
Copyright© 2018 by RWDI. All rights reserved.
Sensitivity to Corner Details
69
Tapered Box
100o Configuration
110o Configuration
120o Configuration 180o Configuration
SHANGHAI TOWER, CHINA - Final ConfigurationCopyright© 2018 by RWDI. All rights reserved.
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Comparison of base overturning moments:
Copyright© 2018 by RWDI. All rights reserved.
Benefits of Optimization: Twist and Building Orientation
Configuration Ratio
Base (Tapered Box) 100%
100o
(107o) 83%
110o (118
o) 79%
180o
(193o) 67%
120o
(129o) - 0° Rot. 71%
110o (118
o) - 30° Rot. 72%
120o - 40° Rot. 67%
Tapering and setbacks
Copyright© 2018 by RWDI. All rights reserved.
Shaping Strategies
Varying cross-section shape
Spoilers Porosity or openings
“Softened” corners
Copyright© 2018 by RWDI. All rights reserved.
Sensitivity to Corner Details
“Hardened” cornersSlotted Corners Chamfered Corners Basic Fins
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Exposed structure at edges – big response increase
Sensitivity to Corner Details
Copyright© 2018 by RWDI. All rights reserved.
Corner Modifications
Mitigation
Copyright© 2018 by RWDI. All rights reserved.
Building Motions
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
Copyright© 2018 by RWDI. All rights reserved.
Accelerations
Structural Wind Load Studies:Input And Output
Copyright© 2018 by RWDI. All rights reserved.
• 3D model of the building or full drawing package
• Information on surrounding buildings
• Information on building code and return period
• Structural dynamic properties
• Assumed damping
• Maximum base reactions
• Floor-by-floor equivalent static wind loads
• Predicted accelerations and torsional velocities
• Sensitivity analysis of the above to damping, natural frequencies and mass
Copyright© 2018 by RWDI. All rights reserved.
Structural Assessments
Input required
Wind-Related Issues in the Design of Buildings
Copyright© 2018 by RWDI. All rights reserved.
THANK YOUDerek Kelly, P.Eng.Building Performance [email protected]
RWDI.COM KNOWLEDGE LEARNING LAB
Copyright© 2018 by RWDI. All rights reserved.
rwdi.com