Honjo International Scholarship Foundation (2013 - Seminar Presentation)

1. Soulachack SOUKSIVONGXAY
The Mechanism of Aeroelastic Vibration on
2-Edge-Girder Bridge by Computational Fluid Dynamics
2013.5.19
数値流体解析によるエッジガーダー橋
の空力弾性振動メカニズム
スラチャック スクシーウォンサイ

2. The Mechanism of Aeroelastic Vibration on
2-Edge-Girder Bridge by Computational Fluid Dynamics
1. About the Bridge Structure
・ the classification of bridge
・ the structural partial of bridge
・ damaged bridges due to natural disaster(EQ, Typhoon…)
2. Wind-Bridge’s Relationship
・ the collapse of Tacoma Bridge
・ wind tunnel experiment & PIV experiment
・ wind-induced vibration’s phenomenon
3. Master Research’s Contents and Results
・ study’s background & purpose
・ analysis results (Static and Dynamic)
・ conclusion

3. ◆ The Classification of Bridge
① Material
concrete bridge, steel bridge, wooden bridge, stone bridge …
② Usage
high way bridge, railway bridge, pedestrian bridge…
③ Road Surface
deck bridge, through bridge, haft through bridge…
④ Support Type
simple bridge, continuous bridge, gerber bridge…
⑤ Structural Type
girder bridge, cable-stayed bridge, suspension bridge, truss
bridge, arch bridge, rigid-frame bridge

4. ◆ Structural Type
girder bridge cable stayed bridge
(yokohama bay bridge)
suspension bridge
(akashi kaikyo bridge)
truss bridge
(tokyo gate bridge)
arch bridge
Omishima bridge
rigid-frame bridge
tomata bridge
H=298m
H=333m

5. ◆ The Structural Partial of Bridge
Handraiｌ（高欄）
Slab（床版）
Main Girder
（主桁）
Pier（橋脚）
Bearing
（支承）
girder bridge
Pavement（舗装）
① ② ③

6. ◆ The Collapse of Tacoma Bridge
・wind tunnel experiment & PIV experiment
⇒ to investigate the wind resistance characteristic
・sine 1940 , wind-bridge engineering became to consider
the wind - induced vibration’s phenomenon
Tacoma Suspension Bridge(1940)
・ until 1940, only wind load was
considered to the wind resistance design
・ Tacoma Bridge: under wind load
(≒wind velocity 60m/s) was designed.
but the torsional flutter vibration
was occurred at 19m/s

7. ◆ Wind Tunnel Experiment & PIV Experiment
understand the separated flow,
stream line, reattachment
property…etc,
wind
Wind Tunnel Experiment PIV Experiment
smooth – turbulence flow
(simulate the real wind’s PSD)
psd
frequency
vortex-induced vibration
flutter vibration
disp
wind velocity
:case1
:case2
:case3
bridge’s model

8. vortex-Induced vibration（渦励振）, torsional flutter, rain –
vibration, galloping, gust responded vibration…etc,
◆ Wind-Induced Vibration’s Phenomenon
① Vortex-Induced Vibration
vortex’s frequency( )
large negative pressure( )
 Hzfst
 PaP
wind
Karman Vortex Shedding
external aero-
dynamic force
the periodic external force due to the vortex shedding
is applied on the body surface
⇒ happen at the small wind velocity & limited amplitude

9. ① Vortex-Induced Vibration
vortex’s frequency( )
large negative pressure( )
 Hzfst
 PaP
wind
External aero-
dynamic force
the periodic external force due to the vortex shedding
is applied on the body surface
⇒ happen at the small wind velocity & limited amplitude
◆ Wind-Induced Vibration’s Phenomenon
vortex-Induced vibration（渦励振）, torsional flutter, rain –
vibration, galloping, gust responded vibration…etc,

10. ② Rain Vibration
water route
windrain
wind
cablevibration
the water route generated on the cable surface deform
the cable’s section
⇒ happen at the low wind velocity & light raining
rain
◆ Wind-Induced Vibration’s Phenomenon
Fred Hartman Bridge(America,1995)
vortex-Induced vibration（渦励振）, torsional flutter, rain –
vibration, galloping, gust responded vibration…etc,

11. The Mechanism of Aeroelastic Vibration on
2-Edge-Girder Bridge by Computational Fluid Dynamics
1. About the Bridge Structure
・ the classification of bridge
・ the structural partial of bridge
・ damaged bridges due to natural disaster(EQ, Typhoon…)
2. Wind-Bridge’s Relationship
・ the collapse of Tacoma Bridge
・ wind-induced vibration’s phenomenon
・ wind tunnel experiment & PIV experiment
3. Master Research’s Contents and Results
・ study’s background & purpose
・ analysis results (Static and Dynamic)
・ conclusion

12. Edge Girder Bridge a few main girder bridge’s type
construction・economic advantage apply to long-span bridge
Alex fraser bridge（canada・cable-stayed bridge・main span : 460m・1986 complete）
Nanpu bridge（china・cabel-stayed bridge・main span : 423m・1991 complete）
Binh bridge（vietnam・cable-stayed bridge・main span : 260m・2005 complete）
Choshi bridge（japan・cable-stayed bridge・main span192.6m・2010 complete）
the edge girder long-span bridge was adopted
in Japan is very less

13. ❏ investigation by wind tunnel testing:
to clarify the aerodynamic vibration generating ’s
mechanism quantitively is difficult
✓
❏ Problem of Edge Girder Bridge:
low torsional stiffness ⇒ instability of wind-resistant
✓
wind
wind tunnel testing Computational Fluid Dynamic(CFD)
applying the CFD with the wind tunnel testing the efficiency
of wind-stability investigation can be expected more
Edge Girder Bridge a few main girder bridge’s type
bridge model

14. Study’s Purpose:
to clarify the aerodynamic vibration on 2 edge girder-
bridge by using CFD
previous wind tunnel testing（2000）
CFD model（2D・B÷D=10）
D
C
B
❏ Static Analysis
・ 3 components of aerodynamic force coefficient, separated flow –
pattern … etc,
❏ Dynamic Analysis
・ 1DOF torsion・vertical vibration’s unsteady aerodynamic force,
surface pressure distribution … etc,
・ to verify the Separation Interference
Method(SIM)’s effectiveness
θ handrail
C÷D：overhanging ratio

15. ①Stationary Region
②Moving Region(Overset Mesh）
Overlap boundary condition
No-slip(U=V=0)
（body’s surface）
D
B
40D
10D
60D
20D
Moving
・2D（RANS）・重合格子法（Overset Meshing Method）
（the mesh is not change when the body is moving）
tfyty y2sin)( 0
tft  2sin)( 0
C
・forced vibration method
1DOF vertical vibration ⇒
1DOF torsional vibbration ⇒
Moving
Slip （U≠0,V=0）
Inlet(smoothfow)
Outlet（P=0）
inlet flow Smooth flow
torsional angle θ0 0.5～13°
vertical disp y0 0.1D～2.5D
time step（Δt） 0.005s
total of elements 29100～34200
mesh’s division
Mesh①～④
（2.5,5,10,25mm）
Analysis’s Parameters
Mesh①
Mesh② Mesh③
Mesh④Slip （U≠0,V=0）

16. ②
④ ⑥
⑧
Smooth Flow: U
Pressure(Pa)
（C÷D=0.5・Ur=U/f.D=80）

17. ②
④ ⑥
⑧
negative pressure
positive moment
①
②
③
④
⑤
⑥ ⑧：torsional angle
: pitching moment
t(s)
LM CC ,
0/
⑦
：lift force
positive moment & Lift
Θ
D
C
B
（B÷D=10,C÷D=0.5）
Pressure(Pa)
Smooth Flow: U
upward torsion
downward torsion
excitation force’s situation
（C÷D=0.5・Ur=U/f.D=80）
downward torsion
upward torsion
positive M
negative P
negative P
negative M
negative M
negative P

18. ④ ⑥
⑧
①
②
③
④
⑤
⑥ ⑧：torsional angle
: pitching moment
t(s)
LM CC ,
0/
⑦
：lift force
positive moment & Lift
Θ
D
C
B
（B÷D=10,C÷D=0.5）
Pressure(Pa)
Smooth Flow: U
downward torsion
（C÷D=0.5・Ur=U/f.D=80）
downward torsion
upward torsion
positive M
negative P
negative P
negative M
negative M
negative P
③
negative P
positive M
(Max)
upward torsion
excitation force’s situation

19. ● the separated bubble appeared on the upper surface
(upsteam side) generate the excitation force dominantly
torsional flutter generation’s main cause
Pressure(Pa)
（C÷D=0.5・Ur=U/f.D=80）
④ downward torsion
positive M
negative P
⑥downward torsion
negative P
negative M
⑧ upward torsion
negative M
negative P
③
negative P
positive M
(Max)
upward torsion
excitation force’s situation

20. C÷D=0.5・θ=90° C÷D=0.5・θ=30° C÷D=2.0・θ=90° C÷D=2.0・θ=30°
Instantaneous separated vortex・stream line’s pattern（1DOF torsion,Ur=80）
D
C
handrail
-1.0 1.00.0
B
剥離干渉法（SIM）
aerodynamical damping measure method
（Kubo・JSCE・1992）
suppress the separated flow
1st separated
point
2nd separated point
upper surface unsteady pressure
distribution’s comparison（Ur=80）
2
5.0 U
P
CP

PC
C÷D=0.5
C÷D=2.0
:No handrail :θ=90° :θ=30°
:No handrail :θ=90° :θ=30°
:C÷D=0.5・θ=30°
1DOF torsional vibration ⇒ C÷D=0.5・
θ=30° is the most of SIM effectivenessupper surface
C÷D：overhanging ratio

21. 1. Static Analysis’s Results
using CFD to investigate the aerodynamic vibration on
2 edge girder bridge
1DOF torsional vibration・Ur=80
●
C÷D=0.5 C÷D=2.0
1DOF vertical vibration・Ur=12.5
the static aerodynamic force’s curves are match with the previous
experimental results, C÷D=0.5(outside girder’s installation)
⇒ torsional flutter instability is more decrease
separated bubble
excitation force
2. Dynamic Analysis’s Results
the separated bubble on the upper surface
(upstream side) cause the torsional flutter
●
the separated vortex between
two girders‘ area cause the
vortex shedding vibration
●
● overhanging ratio C÷D=0.5 with handrail (θ=30°) is the most of
Separation Interference method’s effectiveness

22. Soulachack SOUKSIVONGXAY
The Mechanism of Aeroelastic Vibration on
2-Edge-Girder Bridge by Computational Fluid Dynamics
2013.5.19
数値流体解析によるエッジガーダー橋
の空力弾性振動メカニズム
thank you for your kind attention
スラチャック スクシーウォンサイ