Friction Damper with Coned disc springs

1. Friction Damper with Coned disc springs August, 2001 Obayashi Corporation

2. Laminated Rubber Bearing Lead plug Lead Rubber Bearing Natural Rubber Bearing High Damping Rubber Bearing

3. Damper Selection Line-up Oil damper Steel damper Friction damper with Coned disc springs Lead damper

4. Feature of Dampers ③ Oil damper ○ EnergyAbsorption Δ Stroke limit X Directional operation (one direction) X Load Support ① Steel damper Δ EnergyAbsorption Δ Stroke limit Δ Directional operation X Load Support ② Lead damper Δ EnergyAbsorption Δ Stroke limit Δ Directional operation X Load Support ④ Friction damper with Coned disc springs ○ EnergyAbsorption Δ Stroke limit ○ Directional operation ○ Load Support

5. Outline of Coned Disc Spring 2b=190 t=11.0 h=14.7 Unit/mm 2a=420

6. Vertical Load-deflection Curves of Coned disc spring 20 15 10 5 0 0 5 10 15 Vertical Displacement (mm) [III] [ II ] Vertical load (tonf) Test Analysis FEM [ I ] Sectional plan of Coned disc spring [III] [ II ] [ I ]

7. 0 10 20 30 40 0 10 20 30 40 0 10 20 30 40 0 10 20 30 40 Combination of Coned disc springs Single Disc Two columns of single disc 40 40 30 30 [tonf] [tonf] 20 20 10 10 0 0 [mm] [mm] Double Discs Two columns of double discs 40 40 30 30 [tonf] 20 [tonf] 20 10 10 0 0 [mm] [mm]

8. Feature of Coned disc spring ・Get big Resilient force by compact sized coned disc spring ・Linear or nonlinear load-defection curve can be gained by coned disc spring ・Get many kind of load-deflection curve by combination coned disc springs ・Use semi-permanently under allowable stress

9. Outline of Friction Damper with Coned disc springs 560 Inner Guide Coned disc springs Height of Coned disc springs/ 240 460 Sliding material Stainless Steel Plate 400 Unit / mm

10. Principle of the Friction damper of Coned disc Springs Friction force Movement W : Weight F : Friction force Friction force F=W : Frictional coefficient Superstructure Coned disc springs Resilient force N Resilient force N Rubber bearing Horizontal Friction Force F Foundation Compress the multiple coned disc springs to occur resilient force Sliding plate (UHMWP) Stainless steel plate Horizontal friction force F is occurred when pressing down the sliding plate(UHMWP) by multiple coned disc springs resilient force N against stainless steel plate F N :Frictional coefficient

11. Independence of the height changes of rubber bearing In the state of the rubber bearing height becomes shortby low temperature and creep In the state of the rubber bearing height becomes high by high temperature Up-lift : b Go-down : a Resilient force N2 Resilient force n2 Resilient force n1 Resilient force N1 Initial height Initial height Linear spring Nonlinear coned disc springs Nonlinear coned disc springs Linear spring [Linear spring] [Nonlinear coned disc springs] Resilient force Resilient force Resilient variation force of nonlinear coned disc springs is smaller than that of linear spring by change of rubber bearing height, and variation of friction force is so. n1 N1 n2 N2 Vertical displacement Vertical displacement b a b a

12. For supporting function of the friction damper with coned disc springs Normal time Emergent excessive earthquake Weight 100% Weight 100% Superstructure Superstructure Support 25% Support 75% Support 10% Rubber bearing Support 90% Foundation Foundation Stainless steel plate In emergent excessive earthquake, rubber bearing will have large horizontal displacement and cannot support superstructure, then the friction damper takes support it ins In normal time, most of superstructure weight is supported by rubber bearing (ex. 75%)

13. 0.4 0.2 0 -0.2 -0.4 -200 -40 -150 -30 -20 -100 -10 -50 0 0 10 50 100 20 30 150 40 200 0.4 0.2 0 -0.2 -0.4 Horizontal hysteresis loops of the Friction damper with coned disc springs [For Wind Load] Frictional coefficient Horizontal displacement (mm) [For EQ Load] Frictional coefficient Horizontal displacement (mm)

14. Multi Function for the friction damper with coned disc springs 1. Restrain the movement by strong wind (Improvement for dwelling ability) 2. Stable damper for earthquake (Damper function) 3. Support load function (Safety device function)

15. New Base Isolation Building Oil Damper Friction damper with coned disc springs The new base-isolation building in Nagoya

16. The new base-isolation building in Nagoya Oil damper Friction damper with coned disc springs Friction damper with coned disc springs Oil damper Rubber bearing Rubber bearing Plan Elevation

17. 40 35 30 25 20 15 Available zone 10 5 0 20 30 40 50 60 70 80 0 10 12 8 4 0 -4 -8 -12 -200 -150 -100 -50 0 50 100 150 200 Feature of the friction damper with coned disc springs Vertical force (tonf) Inner Guide Vertical displacement (mm) Vertical load-deflection curves Multiple coned disc springs Friction force (tonf) Stainless steel plate Sliding Plate Outline of the friction damper with coned disc springs Horizontal displacement (mm) Horizontal hysteresis loops

18. Feature of the friction damper with coned disc springs ・Adjust the friction force by the combination coned disc springs of the friction damper ・To operate in all direction, and stroke is limited by the area of stainless steel plate ・Friction force is stable constant ・Friction damper can support the load ・Easy to set the friction damper with coned disc springs