Friction Damper with Coned disc springs

August, 2001

Obayashi Corporation

Laminated Rubber Bearing

Natural Rubber Bearing Lead Rubber Bearing

High Damping Rubber Bearing

Lead plug

Damper Selection Line-up

Steel damper Oil damper

Lead damper Friction damper with Coned disc springs

Feature of Dampers

① Steel damperΔ Energy AbsorptionΔ Stroke limit Δ Directional operation X Load Support

③ Oil damper○ Energy AbsorptionΔ Stroke limit X Directional operation (one direction) X Load Support

② Lead damperΔ Energy AbsorptionΔ Stroke limit Δ Directional operation X Load Support

④ Friction damper with Coned disc springs○ Energy AbsorptionΔ Stroke limit ○ Directional operation○ Load Support

Outline of Coned Disc SpringOutline of Coned Disc Spring

2b=190

h=14

.7

2a=420 Unit/mm

t=11.0

Vertical Load-deflection Curves Vertical Load-deflection Curves of Coned disc spring of Coned disc spring

Sectional plan of Coned disc spring

0 5 10 150

5

10

15

20

[ I ]

[III]

[ I ] [ II ] [III]

Vertical Displacement (mm)

Vert

ical

load

(ton

f)

[ II ]

TestAnalysisFEM

Combination of Coned disc springsCombination of Coned disc springs

Single Disc Two columns of single disc

Double Discs Two columns of double discs

40

10

20

30

40

10

20

30

40

10

20

30

40

10

20

30

0

0

04010 20 300

0

4010 20 300

4010 20 300 4010 20 300

[mm]

[tonf

][to

nf]

[tonf

][to

nf]

[mm]

[mm] [mm]

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

Outline of Friction Damper Outline of Friction Damper with Coned disc springswith Coned disc springs

560

400 Unit / mm

460

Hei

ght o

f C

oned

dis

c sp

ring

s/ 2

40Inner Guide

Coned disc springs

Sliding material

Stainless Steel Plate

Principle of the Friction damper Principle of the Friction damper of Coned disc Springsof Coned disc Springs Movement

W : Weight

F : Friction force

Friction force

F=W : Frictional coefficientSuperstructure

Rubber bearing

Foundation

Resilient force N

Horizontal Friction Force F

Stainless steel plateCompress the multiple coned disc springs to occur resilient force

Resilient force N

Coned disc springs

Sliding plate (UHMWP)

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

Friction force

Independence of the height changes of rubber bearingIndependence of the height changes of rubber bearing

Go-down : a

Initial height

Linear spring Nonlinear coneddisc springs

Resilientforce N1

Resilientforce n1

Up-lift : b

Resilientforce n2

Resilientforce N2

Nonlinear coneddisc springs

Linear spring

[Linear spring]Resilient force

[Nonlinear coned disc springs]

Vertical displacement

Resilient variation force of nonlinear coned disc springsis smaller than that of linearspring by change of rubberbearing height, and variationof friction force is so.

n1

n2N1N2

abab

In the state of the rubber bearing height becomes short by low temperature and creep

In the state of the rubber bearing height becomes high by high temperature

Resilient force

Vertical displacement

Initial height

For supporting function of the friction damperFor supporting function of the friction damper with coned disc springs with coned disc springs

Normal time Emergent excessive earthquake

Weight 100%

Support 75% Support 10%Support 25%

Support 90%Foundation

Superstructure

Stainless steel plate

In normal time, most of superstructure weight is supported by rubber bearing (ex. 75%)

In emergent excessive earthquake, rubber bearing will have large horizontal displacement and cannot support superstructure, then the friction damper takes support it ins

Rubber bearing

Weight 100%

Foundation

Superstructure

Horizontal hysteresis loops of the Friction daHorizontal hysteresis loops of the Friction damper with coned disc springsmper with coned disc springs

0.4

0.2

0

-0.2

-0.4

0.4

0.2

0

-0.2

-0.4

-40 -30 -20 -10 0 10 20 30 40

-200 -150 -100 -50 0 50 100 150 200

Fric

tion

al c

oeff

icie

nt

Horizontal displacement (mm)

[For Wind Load]

[For EQ Load]

Fric

tion

al c

oeff

icie

nt

Horizontal displacement (mm)

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)

Multi Function for the friction damper with coned disc springs

New Base Isolation Building

The new base-isolation building in NagoyaFriction damper with

coned disc springs

Oil Damper

The new base-isolation building in Nagoya

Elevation Plan

Oil damperFriction damper with coned disc springs

Rubber bearing

Rubber bearing

Friction damper with coned disc springs

Oil damper

0 10 20 30 40 50 60 70 80

10

0

5

1520

3025

3540

Available zone

-200 -150 -100 -50 0 50 100 150 200

128

04

-4-8

-12

Stainless steel plateMultiple coned disc springs

Sliding Plate

Inner Guide

Feature of the friction damperFeature of the friction damper with coned disc springswith coned disc springs

Outline of the friction damper with coned disc springs

Vertical load-deflection curves

Horizontal hysteresis loops

Fri

ctio

n fo

rce

(ton

f)V

erti

cal

forc

e (t

onf)

Vertical displacement (mm)

Horizontal displacement (mm)

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