blanchet_tall_buildings_wind_tunnel.pdf

8/10/2019 Blanchet_Tall_Buildings_Wind_Tunnel.pdf

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Tall Building AnalysisTall Building Analysis

in GT STRUDL forin GT STRUDL for

Wind Tunnel StudiesWind Tunnel Studies

Craig D. Blanchet, P.E.Craig D. Blanchet, P.E.

AssociateAssociate

LeMessurier ConsultantsLeMessurier Consultants


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OutlineOutline

Wind Related Issues for Tall BuildingsWind Related Issues for Tall Buildings

Wind Tunnel StudiesWind Tunnel Studies Goals & MethodsGoals & Methods

Modeling & Analysis ConsiderationsModeling & Analysis Considerations

Boston Theatre District HotelBoston Theatre District Hotel

GT STRUDL v29GT STRUDL v29

My GT STRUDL Wish ListMy GT STRUDL Wish List


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Wind & Tall BuildingsWind & Tall Buildings

Important Design ConsiderationsImportant Design Considerations

1.1. StrengthStrength MainMain WindWind ForceForce ResistingResisting SystemSystem

2.2. StiffnessStiffness

DriftDrift

DynamicDynamic ResponseResponse


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StrengthStrength

uF

)oror(5.06.12.1 RSLLWD r++++++++++++====

)0.8or()oror(6.12.1 WLRSLD r ++++++++====

HWD 6.16.19.0 ++++++++====

nu MM nu PP nu VV

0.12

23

2

121 ++++++++

n

u

n

u

n

u

M

M

M

M

P

P


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StiffnessStiffness

sec/story0.18.0 =

T

BW

H

BH

ave

Equation relating driftEquation relating driftto period. Proposed byto period. Proposed byWilliam J. LeMessurier.William J. LeMessurier.

Target period basedTarget period basedon past experience.on past experience.

= Building Density (lbs/ft= Building Density (lbs/ft33))

BB = Building Width (ft)= Building Width (ft)

HH = Building Height (ft)= Building Height (ft)

= Top Displacement (ft)= Top Displacement (ft)

WWaveave = Average Wind Pressure (lbs/ft= Average Wind Pressure (lbs/ft22

))


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StiffnessStiffness Dynamic ResponseDynamic Response

VortexVortex SheddingShedding

DrDr.. TheodoreTheodore vonvon KarmenKarmenWhenWhen windwind passespasses aroundaround aa bluffbluff bodybody

areare shedshed fromfrom eacheach sideside ofof thethe bodybody..


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mph6050 V Vortices shed symmetrically inVortices shed symmetrically inpairs. Alongpairs. Along--wind impulses only.wind impulses only.

mph6050 >>>>V Vortices shed alternatelydownwind from each side at

the frequency of the along-windimpulses. Along-wind and cross-wind impulses.


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VortexVortex SheddingShedding AlongAlong--windwind ResponseResponse

gDe

pDDC

CKsFgna

224====

aa nn = Fundamental Frequency (Hz)= Fundamental Frequency (Hz)ggpp = Peak Factor= Peak FactorKK = Surface Roughness Coefficient= Surface Roughness Coefficientss = Size Reduction Factor= Size Reduction FactorFF = Gust Energy Ratio= Gust Energy RatioCCee = Exposure Factor= Exposure Factor = Critical Damping Ratio= Critical Damping Ratio = Top Displacement (ft)= Top Displacement (ft)CCgg = Gust Response Factor= Gust Response Factor


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VortexVortex SheddingShedding CrossCross--windwind ResponseResponse

====

W

rpWW

gaWDgna

2

aa nn = Fundamental Frequency (Hz)= Fundamental Frequency (Hz)ggpp = Peak Factor= Peak FactorWW = Cross= Cross--wind Plan Dimension (ft)wind Plan Dimension (ft)DD = Along= Along--wind Plan Dimension (ft)wind Plan Dimension (ft)aarr = Acceleration Factor (ft/s= Acceleration Factor (ft/s

22)) = Average Building Density (lbs/ft= Average Building Density (lbs/ft33))gg = Acceleration Due to Gravity (ft/s= Acceleration Due to Gravity (ft/s22)) = Critical Damping Ratio= Critical Damping Ratio


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CrossCross--windwind ResponseResponse UsuallyUsually ControlsControls WhenWhen

1WD

3H

WW = Cross= Cross--wind Plan Dimension (ft)wind Plan Dimension (ft)

DD = Along= Along--wind Plan Dimension (ft)wind Plan Dimension (ft)HH = Building Height (ft)= Building Height (ft)


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Von Krmn Vortex StreetVon Krmn Vortex Street


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Vortex Shedding EquationsVortex Shedding Equations

ff = Frequency of Vortex Shedding= Frequency of Vortex Shedding

D

SVf ====

====Re

S7.19

1198.0

VV = Steady Upstream Wind Velocity= Steady Upstream Wind VelocityDD = Building Width or Diameter= Building Width or Diameter

SS = Strouhal Number= Strouhal Number (~0.20 cyl., ~0.13 sq.)(~0.20 cyl., ~0.13 sq.)

Varies with wind velocityVaries with wind velocityReRe = Reynolds Number= Reynolds Number


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mph6050 V Vortices shed symmetrically inVortices shed symmetrically inpairs. Alongpairs. Along--wind impulses only.wind impulses only.

RecallRecallVortexVortex SheddingShedding

mph6050 >>>>V Vortices shed alternatelydownwind from each side at

the frequency of the along-windimpulses. Along-wind and cross-wind impulses.


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Critical Wind VelocityCritical Wind Velocity

S

DfV bldgcrit====

ResonanceResonance

--SlightSlight changeschanges inin VV willwill not not changechange thethefrequencyfrequency ofof vortexvortex sheddingshedding becausebecause thethe

sheddingshedding becomesbecomes controlledcontrolled by by thetheoscillationsoscillations ofof thethe buildingbuilding.. Lock Lock--inin occursoccurs

withinwithin aboutabout 1010%% ofofffbldgbldgsoso aa preciseprecise valuevalue ofof

SSisis unnecessaryunnecessary..


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Wind Tunnel StudiesWind Tunnel Studies

Goals & MethodsGoals & Methods

1.1. LoadsLoads PressurePressure ModelModel WindWind speedsspeeds forfor pedestrianpedestrian comfortcomfort

PressuresPressures onon cladding,cladding, roofs,roofs, soffits,soffits, etcetc

ForcesForces onon primaryprimary structuralstructural systemsystem

2.2. DynamicDynamic EffectsEffects ForceForce BalanceBalance ModelModel

ResponseResponse toto buffetingbuffeting andand vortexvortex sheddingshedding

PeakPeak forcesforces onon primaryprimary structuralstructural systemsystem(combined(combined resultsresults withwith pressurepressure model)model)

EffectEffect ofof motionsmotions onon occupantsoccupants


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Boundary Layer Wind TunnelBoundary Layer Wind Tunnel


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Pressure ModelPressure Model -- VorticesVortices


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Cladding PressuresCladding Pressures


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Coordinate SystemCoordinate System


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Modes & FrequenciesModes & Frequencies


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Mode ShapesMode Shapes


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Forces BalanceForces Balance


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ViscoelasticViscoelastic DampingDamping

ViscousViscous DampersDampers

TunedTuned MassMass DampersDampers

DampingDamping

2

'

bldgofmassdgeneralize

TMDofmassactive

=

TMD

top

laddn

Additional Damping For a Given ModeAdditional Damping For a Given Mode


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112112 storiesstories

500500 metermeter ++ 100100 metermeter spirespire((16401640 ft)ft) ((328328 ft)ft)

22ndnd Lotte WorldLotte World

Super TowerSuper Tower

,, mm ((33,,000000,,000000 ftft22

)) 55 LevelsLevels BelowBelow GradeGrade

ChallengingChallenging GeometryGeometry

CustomCustom SoftwareSoftware


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PreliminaryPreliminary 22DD ModelsModels

TestTest ModelsModels

33DD ModelModel

22ndnd Lotte WorldLotte World

Super TowerSuper Tower

RhinoRhino OBJOBJ toto GTIGTI

GTGT STRUDLSTRUDL ModelModel

StatisticsStatistics && ResultsResults DynDyn.. WindWind TunnelTunnel PropsProps

WindWind TunnelTunnel RecommendationsRecommendations

SchematicSchematic DesignDesign


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Preliminary ModelsPreliminary Models


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Virtual Work OptimizationVirtual Work Optimization


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Test ModelsTest Models


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Test ModelsTest Models -- SpeedSpeed


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Test ModelsTest Models

StiffnessStiffness


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OBJ to GTIOBJ to GTI

WavefrontWavefront OBJOBJ FileFile

SimpleSimple ASCIIASCII TextText

MSWordMSWord VBAVBA

25542554 LinesLines ofof CodeCode

1717 SubroutinesSubroutines

WriteWrite GTIGTI FileFile


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OBJ to GTIOBJ to GTI


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OBJ to GTIOBJ to GTI Input DialogInput Dialog


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GT STRUDL ModelGT STRUDL Model

2762027620 JointsJoints

1492514925 MembersMembers

2468624686 ElementsElements

1571015710 IPLQ/CSTGIPLQ/CSTG

BandwidthBandwidth108108..516516 ++ 117117..862862


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GT STRUDL ModelGT STRUDL Model

22 11..00 GHzGHz PentiumPentium IIIIII

11..00 GBGB RAMRAMGTGT STRUDLSTRUDL vv2626

StiffnessStiffness AnalysisAnalysis 1919 minmin 2828 secsecDynamicDynamic AnalysisAnalysis 33 ModesModes

EigensolutionEigensolution:: 9797 minmin 1818 secsec

ChecksChecks:: 5858 minmin 3232 secsec

#1#1 6 64 316 64 31


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Mode #1Mode #1 T=6.64731 secT=6.64731 sec

M d #2M d #2 T 6 54169T 6 54169


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M d #3M d #3 T 4 91990T 4 91990


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F B l M d lF B l M d l


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Force Balance ModelForce Balance Model


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R d tiR d ti


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RecommendationsRecommendations

TMD to reduce torsional velocities belowTMD to reduce torsional velocities below

3 milli3 milli--rad/secrad/sec

Additional 1% damping requiredAdditional 1% damping required

DesignDesign Corner Col mnsCorner Col mns


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DesignDesign Corner ColumnsCorner Columns

DesignDesign Tie BeamsTie Beams


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DesignDesign Tie BeamsTie Beams


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Boston TheatreBoston Theatre


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District HotelDistrict Hotel

2626 storiesstories

310310 feetfeet

5050%% HotelHotel // 5050%% CondoCondo

22 LevelsLevels BelowBelow GradeGrade

IrregularIrregular FootprintFootprint

NonNon--parallelparallel SystemsSystems

TorsionalTorsional ModesModes



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District HotelDistrict Hotel OriginalOriginal SchemeScheme ((20012001))

NewNew Owner/SchemeOwner/Scheme ((20052005)) 33DD ModelModel

RhinoRhino -- DXFDXF

GTGT STRUDLSTRUDL ModelModel VirtualVirtual WorkWork StudiesStudies

StatisticsStatistics && ResultsResults DynDyn.. WindWind TunnelTunnel PropsProps


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Original SchemeOriginal Scheme


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Original SchemeOriginal Scheme


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New Owner/Scheme (2005)New Owner/Scheme (2005)


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New Owner/Scheme (2005)New Owner/Scheme (2005)

5050%% Hotel,Hotel, 5050%% CondoCondo

UseUse SameSame FramesFrames w/w/ ModificationsModifications @@ TopTop

1515 millimilli--g/secg/sec CriterionCriterion

--

ModificationsModifications @@ TopTop DecreaseDecrease StiffnessStiffness

SolvedSolved 2121 psfpsf StructuralStructural SteelSteel

OriginallyOriginally 1818 psfpsf ((1616..77%% Increase)Increase)

Modified SchemeModified Scheme


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Modified SchemeModified Scheme

LineLine 33 LineLine 55 LineLine 99 LineLine 1212

NONOZipper ColumnsZipper ColumnsNONO

TransfersTransfers

$$$ WINS!!!$$$ WINS!!!

Longitudinal FramesLongitudinal Frames


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Longitudinal FramesLongitudinal Frames


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Virtual Work StudiesVirtual Work Studies


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Virtual Work StudiesVirtual Work Studies

FinalFinal SchemeScheme


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FinalFinal SchemeScheme

--26%26%

--1%1% --17%17%

AverageAverage



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Mode #1Mode #1 T 4.16339 secT 4.16339 sec



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Mode #2Mode #2 T 2.40004 secT 2.40004 sec



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Mode ShapesMode Shapes


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pp

GT STRUDLGT STRUDL 29 Beta29 Beta


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22ndndLotte World Super TowerLotte World Super Tower

v28v28 v29v29

Stiffness Analysis TimeStiffness Analysis Time 897.62897.62 173.22173.22

..

Eigensolution TimeEigensolution Time 746.44746.44 224.68224.68

3.32x3.32x

Eigensolution Check TimeEigensolution Check Time 514.35514.35 173.55173.55

2.96x2.96x

My GT STRUDLMy GT STRUDL Wish ListWish List


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yy

Analysis & DesignAnalysis & Design

Virtual Work Based DeflectionVirtual Work Based Deflection

OptimizationOptimization

Communication with BIM roductsCommunication with BIM roducts

Open database for access from objectOpen database for access from objectoriented programming interfaces (.NET etc)oriented programming interfaces (.NET etc)

Accomplish via DBX files?Accomplish via DBX files?

GraphicalGraphical

Visualize Specified MassesVisualize Specified Masses

Output Animation Files (mpeg, etc.)Output Animation Files (mpeg, etc.)

blanchet_tall_buildings_wind_tunnel.pdf

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