1. Scissor-Jack-Damper System for Reduction of Stay Cable
The 18th KKCNN, Kaohsiung, Taiwan
18-21, December, 2005
Scissor-Jack-Damper System
for Reduction of Stay Cable
Chul-Min Park*: Graduate Student, KAIST, Korea
Hyung-Jo Jung: Professor, Sejong University, Korea
Ji-Eun Jang: Graduate Student, KAIST, Korea
Kyu-Sik Park: Post Doctoral Fellow, UIUC, USA
In-Won Lee: Professor, KAIST, Korea

2. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Contents
Introduction
Toggle-Brace-Damper System
Analytical Study on Performance of
Scissor-Jack-Damper
Conclusions
Structural Dynamics & Vibration Control Lab., KAIST, Korea

3. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Introduction
Backgrounds
The novel configuration of Scissor-Jack-Damper results in
device displacements that are larger than the cable drift.
The potential for cost savings and improved performance
Structural Dynamics & Vibration Control Lab., KAIST, Korea

4. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Toggle-Brace-Damper System
Diagonal and chevron brace configuration
Chevron brace
Diagonal brace
Structural Dynamics & Vibration Control Lab., KAIST, Korea

5. Structural Dynamics & Vibration Control Lab., KAIST, Korea
The theory of brace-damper system
(1)
(2)
Structural Dynamics & Vibration Control Lab., KAIST, Korea

6. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Magnification factor in brace system
(3)
(4)
Structural Dynamics & Vibration Control Lab., KAIST, Korea

7. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Toggle-brace-damper configurations
Lower toggle
Upper toggle
Structural Dynamics & Vibration Control Lab., KAIST, Korea

8. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Scissor-jack-damper configuration (Sigaher, A. N. 2003)
Scissor-Jack
Structural Dynamics & Vibration Control Lab., KAIST, Korea

9. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Magnification factor
Type
diagonal brace
chevron brace
upper toggle system
lower toggle system
scissor-Jack-damper
Structural Dynamics & Vibration Control Lab., KAIST, Korea

10. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Analytical Study on Performance of Scissor-Jack-Damper
Cable Dynamics
excitation :
(5)
where, : zero-mean Gaussian white noise process
Structural Dynamics & Vibration Control Lab., KAIST, Korea

11. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Equation of motion
(6)
where,
: transverse deflection of the cable
: viscous damping per unit length
: distributed load on the cable
: transverse damper force at location
Structural Dynamics & Vibration Control Lab., KAIST, Korea

12. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Control oriented model (Johnson et al. 2000)
(7)
Governing equation of motion
(8)
Structural Dynamics & Vibration Control Lab., KAIST, Korea

13. Structural Dynamics & Vibration Control Lab., KAIST, Korea
(9)
(10)
(11)
Structural Dynamics & Vibration Control Lab., KAIST, Korea

14. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Cable characteristics (Christeson 2001)
parameter
value
Structural Dynamics & Vibration Control Lab., KAIST, Korea

15. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Scissor-jack-damper system for stay cable
magnification factor
(12)
damping force exerted on the cable
(13)
Structural Dynamics & Vibration Control Lab., KAIST, Korea

16. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Analytical results
Linear viscous damper
RMS displacement
RMS velocity
optimal
Structural Dynamics & Vibration Control Lab., KAIST, Korea

17. Structural Dynamics & Vibration Control Lab., KAIST, Korea
Scissor-Jack-Damper system
RMS displacement
RMS velocity
optimal
Structural Dynamics & Vibration Control Lab., KAIST, Korea

18. Conclusions Scissor-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 system
- performance degradation
dependent on damper location
Structural Dynamics & Vibration Control Lab., KAIST, Korea

19. Thank you for your attention!
Structural Dynamics & Vibration Control Lab., KAIST, Korea