Soulachack SOUKSIVONGXAY

The Mechanism of Aeroelastic Vibration on 2-Edge-Girder Bridge by Computational Fluid Dynamics2013.5.19

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Tokyo Japanese Education Center(20052006)Nagano National College of Technology(20062009)Yokohama National University(20092011) Institute of Urban Innovation, Master degree(20112013)Kawada Industries Company2013.4.1 Steel Structure Division(Bridge Engineering)Civil EngineeringCivil Engineering, Bridge Engineering

Self-Introduction

Japanese Language

Presentations ContentsThe Mechanism of Aeroelastic Vibration on 2-Edge-Girder Bridge by Computational Fluid Dynamics1. About the Bridge Structurethe classification of bridgethe structural partial of bridgedamaged bridges due to natural disaster(EQ, Typhoon)2. Wind-Bridges Relationshipthe collapse of Tacoma Bridge wind tunnel experiment & PIV experimentwind-induced vibrations phenomenon3. Master Researchs Contents and Resultsstudys background & purposeanalysis results (Static and Dynamic)conclusion

1. About the Bridge Structure The Classification of BridgeMaterial concrete bridge, steel bridge, wooden bridge, stone bridge Usage high way bridge, railway bridge, pedestrian bridgeRoad Surface deck bridge, through bridge, haft through bridgeSupport Type simple bridge, continuous bridge, gerber bridgeStructural Type girder bridge, cable-stayed bridge, suspension bridge, truss bridge, arch bridge, rigid-frame bridge

1. About the Bridge Structure Structural Type girder bridge

cable stayed bridge(yokohama bay bridge)suspension bridge(akashi kaikyo bridge)

truss bridge(tokyo gate bridge)

arch bridgeOmishima bridgerigid-frame bridgetomata bridge

H=298m

H=333 mlongest main span(2 Km)

1. About the Bridge Structure The Structural Partial of Bridge

HandraiSlab

Main GirderPierBearing girder bridgePavement

2. Wind-Bridges Relationship The Collapse of Tacoma Bridgewind tunnel experiment & PIV experiment to investigate the wind resistance characteristicsine 1940 , wind-bridge engineering became to consider the wind - induced vibrations phenomenonTacoma Suspension Bridge(1940) until 1940, only wind load wasconsidered 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

2. Wind-Bridges Relationship Wind Tunnel Experiment & PIV Experiment

understand the separated flow, stream line, reattachment propertyetc,

wind

Wind Tunnel ExperimentPIV Experimentsmooth turbulence flow(simulate the real winds PSD)

psdfrequency

vortex-induced vibrationflutter vibrationdispwind velocity:case1:case2:case3

bridges model

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vortex-Induced vibration, torsional flutter, rain vibration, galloping, gust responded vibrationetc,

2. Wind-Bridges Relationship Wind-Induced Vibrations Phenomenon Vortex-Induced Vibration

vortexs frequency( )large negative pressure( )

wind

Karman Vortex Sheddingexternal 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

2. Wind-Bridges RelationshipVortex-Induced Vibration

vortexs frequency( )large negative pressure( )

wind

External aero-dynamic forcethe periodic external force due to the vortex shedding is applied on the body surface happen at the small wind velocity & limited amplitude

Wind-Induced Vibrations Phenomenon

vortex-Induced vibration, torsional flutter, rain vibration, galloping, gust responded vibrationetc,

2. Wind-Bridges RelationshipRain Vibration

water route

windrainwind

cable

vibrationthe water route generated on the cable surface deform the cables sectionhappen at the low wind velocity & light rainingrain

Wind-Induced Vibrations Phenomenon

Fred Hartman Bridge(America,1995)vortex-Induced vibration, torsional flutter, rain vibration, galloping, gust responded vibrationetc,

Presentations Contents

The Mechanism of Aeroelastic Vibration on 2-Edge-Girder Bridge by Computational Fluid Dynamics1. About the Bridge Structurethe classification of bridgethe structural partial of bridgedamaged bridges due to natural disaster(EQ, Typhoon)2. Wind-Bridges Relationshipthe collapse of Tacoma Bridgewind-induced vibrations phenomenonwind tunnel experiment & PIV experiment3. Master Researchs Contents and Resultsstudys background & purposeanalysis results (Static and Dynamic)conclusion

Edge Girder Bridge a few main girder bridges typeconstructioneconomic advantage apply to long-span bridge

Alex fraser bridgecanadacable-stayed bridgemain span : 460m1986 complete

Nanpu bridgechinacabel-stayed bridgemain span : 423m1991 complete

Binh bridgevietnamcable-stayed bridgemain span : 260m2005 complete

Background and Purpose

Choshi bridgejapancable-stayed bridgemain span192.6m2010 complete

the edge girder long-span bridge was adopted in Japan is very less

investigation by wind tunnel testing: to clarify the aerodynamic vibration generating s mechanism quantitively is difficult

Problem of Edge Girder Bridge: low torsional stiffnessinstability of wind-resistant

windwind tunnel testingComputational 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 bridges type

Background and purpose

bridge model

Studys Purpose:to clarify the aerodynamic vibration on 2 edge girder- bridge by using CFD

previous wind tunnel testing2000

CFD model2DBD=10DCB Static Analysis 3 components of aerodynamic force coefficient, separated flow pattern etc, Dynamic Analysis 1DOF torsionvertical vibrations unsteady aerodynamic force, surface pressure distribution etc,

to verify the Separation Interference Method(SIM)s effectivenesshandrailCDoverhanging ratio

Background and purpose

Stationary Region

Moving Region(Overset MeshOverlap boundary conditionNo-slip(U=V=0)bodys surfaceDB40D10D60D20D

Moving2DRANSOverset Meshing Method the mesh is not change when the body is moving

Cforced vibration method 1DOF vertical vibration 1DOF torsional vibbration

Moving

Slip U0,V=0

Inlet (smooth fow)

Outlet P=0inlet flowSmooth flow torsional angle 00.513vertical disp y00.1D2.5Dtime stept0.005stotal of elements2910034200meshs divisionMesh2.5,5,10,25mm

Analysiss Parameters

Mesh

MeshMesh

Mesh

Slip U0,V=0

Analysis Method, Mesh Shape, Boundary Condition

Static Aerodynamic Force Coefficient's CurveBD=10

aerodynamic moment

: CD=0.5(experiment): CD=2.0(experiment)

: CD=0.5CFD2DRe=32300: CD=2.0CFD2DRe=32300

DC

B

1DOF torsionOkauchi & Miyata1968

torsional flutters condition:

(CFDs results are match with experiments results)CD=0.5 the torsional flutters stability is more decrease

Motions equation:DCattack angleCDoverhanging ratioB

Static Analysiss Results aerodynamic moments curvemoment coef

Smooth Flow:

Pressure(Pa)CD=0.5Ur=U/f.D=80

1DOF Torsional Vibration vortex&aerodynamic forces relation

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negative pressure

positive moment

torsional angle : pitching momentt(s)

lift force

positive moment & Lift

DCBBD=10,CD=0.5

Pressure(Pa)Smooth Flow:

upward torsiondownward torsionexcitation forces situationCD=0.5Ur=U/f.D=80downward torsionupward torsionpositive Mnegative Pnegative Pnegative Mnegative Mnegative P

1DOF Torsional Vibration vortex&aerodynamic forces relation

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torsional angle : pitching momentt(s)

lift force

positive moment & Lift

DCBBD=10,CD=0.5

Pressure(Pa)Smooth Flow:

downward torsionCD=0.5Ur=U/f.D=80

1DOF Torsional Vibration vortex,aerodynamic forces relationdownward torsionupward torsionpositive Mnegative Pnegative Pnegative Mnegative Mnegative P

negative Ppositive M (Max)

upward torsionexcitation forces situation

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the separated bubble appeared on the upper surface (upsteam side) generate the excitation force dominantly torsional flutter generations main cause

Pressure(Pa)

1DOF Torsional Vibration vortex,aerodynamic forces relationCD=0.5Ur=U/f.D=80

downward torsionpositive Mnegative P

downward torsionnegative Pnegative M

upward torsionnegative Mnegative P

negative Ppositive M (Max)

upward torsionexcitation forces situation

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CD=0.5=90CD=0.5=30CD=2.0=90CD=2.0=30Instantaneous separated vortexstream lines pattern1DOF torsion,Ur=80

DC

handrail

-1.01.00.0B

SIM aerodynamical damping measure methodKuboJSCE1992

suppress the separated flow1st separated point2nd separated point

upper surface unsteady pressure distributions comparisonUr=80

CD=0.5CD=2.0:No handrail:=90:=30:No handrail:=90:=30

:CD=0.5=30

1DOF torsional vibration CD=0.5=30 is the most of SIM effectivenessupper surface

Separation Interference Method(SIM)s EffectivenessCDoverhanging ratio

1. Static Analysiss Resultsusing CFD to investigate the aerodynamic vibration on 2 edge girder bridge

1DOF torsional vibrationUr=80 CD=0.5CD=2.01DOF vertical vibrationUr=12.5 the static aerodynamic forces curves are match with the previous experimental results, CD=0.5(outside girders installation) torsional flutter instability is more decrease

separated bubbleexcitation force

Concussion 2. Dynamic Analysiss Resultsthe 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 CD=0.5 with handrail (=30) is the most of Separation Interference methods effectiveness

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Soulachack SOUKSIVONGXAY

The Mechanism of Aeroelastic Vibration on 2-Edge-Girder Bridge by Computational Fluid Dynamics2013.5.19thank you for your kind attention

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