Graduate Student Chul-Min Park*: Graduate Student, KAIST, Korea Hyung-Jo Jung: Professor, Sejong University, Korea Graduate Student Ji-Eun Jang: Graduate.

Chul-Min Park*: Graduate StudentGraduate Student, KAIST, Korea

Hyung-Jo Jung: Professor, Sejong University, KoreaJi-Eun Jang: Graduate StudentGraduate Student, KAIST, Korea

Kyu-Sik Park: Post Doctoral Fellow, UIUC, USA

In-Won Lee: Professor, KAIST, Korea

The 18The 18thth KKCNN, Kaohsiung, Taiwan KKCNN, Kaohsiung, Taiwan

18-21, December, 200518-21, December, 2005

Scissor-Jack-Damper SystemScissor-Jack-Damper System

for Reduction of Stay Cablefor Reduction of Stay Cable

Scissor-Jack-Damper SystemScissor-Jack-Damper System

for Reduction of Stay Cablefor Reduction of Stay Cable

22Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

IntroductionIntroduction

Toggle-Brace-Damper SystemToggle-Brace-Damper System

Analytical Study on Performance of Analytical Study on Performance of Scissor-Jack-DamperScissor-Jack-Damper

ConclusionsConclusions

ContentsContents


Introduction Introduction BackgroundsBackgrounds

• The novel configuration of Scissor-Jack-Damper The novel configuration of Scissor-Jack-Damper results in results in

device displacements that are larger than the cable drift.device displacements that are larger than the cable drift.

• The potential for The potential for cost savingscost savings and and improved performanceimproved performance


Diagonal and chevron brace configuration

Toggle-Brace-Damper SystemToggle-Brace-Damper System

Chevron brace Diagonal brace


damper theof axis thealongnt displaceme relative:

drift interstory:

factor ion magnificat:,where

Du

u

(1)

(2)

damper theof axis thealong force the

forcecomponent horizontalwhere,

DF

F

The theory of brace-damper system


(4)

(3)DD uCF 0

damper theof ends ebetween th velocity relative:

tcoefficien damping:,where 0

Du

C

frame on the exerted force damping the:F

velocityinterstory:,where u

• Magnification factor in brace system


Toggle-brace-damper configurations

Lower toggle Upper toggle


Scissor-jack-damper configuration (Sigaher, A. N. 2003)

Scissor-Jack


Magnification factorMagnification factor

Type

diagonal brace

chevron brace

upper toggle system

lower toggle system

scissor-Jack-damper


Analytical Study on Performance of Scissor-Jack-DamperAnalytical Study on Performance of Scissor-Jack-Damper

Cable Dynamics

excitation :

where, : zero-mean Gaussian white noise process

(5)


where, ),( txv

c),( txf

)(tFd

: transverse deflection of the cable

: viscous damping per unit length

: transverse damper force at location

: distributed load on the cable

Equation of motionEquation of motion

(6)

dx


Governing equation of motionquation of motion

,where

][

][

][

ij

ij

ij

k

c

m

k

C

M

Control oriented model (Johnson et al. 2000)Control oriented model (Johnson et al. 2000)

(7)

(8)


dxxtxftf

dxxxk

dxxxcc

dxxxm

ii

jiij

jiij

jiij

1

0

1

02

1

0

1

0

)(),()(

)()(1

)()(

)()(

Tmffft ][)(vectorloadappliedexternally 21 ff

Tdmddd xxxx )]()()([)(vectorloaddamper 21

(9)

(10)

(11)


Cable characteristics (Christeson 2001)Cable characteristics (Christeson 2001)

parameter

value parameter

value


Scissor-jack-damper system for stay cableScissor-jack-damper system for stay cable

,30for

• magnification factormagnification factor

• damping force exerted on the cabledamping force exerted on the cable

(12)

(13)

73.1


0.025

0.03

0.035

0.04

0.045

0 300 600 900 1200

Damping coefficient(Nsec/m)

RM

S_di

spl(m

)

Analytical resultsAnalytical results

• optimaloptimal mNc sec/650

Linear viscous damperLinear viscous damper

• RMS displacementRMS displacement • RMS velocityRMS velocity

0.3

0.35

0.4

0.45

0.5

0 300 600 900 1200


RM

S_ve

loci

ty(m

/sec

)


• optimaloptimal mNc sec/150

Scissor-Jack-Damper system Scissor-Jack-Damper system

• RMS displacementRMS displacement • RMS velocityRMS velocity

0.3

0.38

0.46

0.54

0.62

0 200 400 600 800


RM

S_ve

loci

ty(m

/sec

)0.025

0.032

0.039

0.046

0.053

0 200 400 600 800


RM

S_di

spl(m

)

Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea 1818

Conclusions

Scissor-Jack-DamperScissor-Jack-Damper configuration

- more efficient to stay cable

- increases the damping force exerted on the cable

- reduces the required damper capacity

Limitation of passive damping systempassive damping system

- performance degradation

dependent on damper location

Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea 1919

Thank you for your attention!

Graduate Student Chul-Min Park*: Graduate Student, KAIST, Korea Hyung-Jo Jung: Professor, Sejong University, Korea Graduate Student Ji-Eun Jang: Graduate.

Documents

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damper system slide

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jackdamper scissorjack

scissorjack slide

brace system slide

korea togglebrace

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