seismic reponse of structures using dcfp bearings with tri-linear and bi-linear behaviours

8/21/2019 Seismic Reponse of Structures Using DCFP Bearings With Tri-Linear and Bi-Linear Behaviours

1/9

Available online at www.sciencedirect.com

The Twe

SEI

USIN

Abstract

Double conc

consists of t

structures usi

coupled diffe

response of

behavior ove

amplitude of

earthquakes.

base shear u

than bi-linear

2011 Pub

Keywords:Do

1. Introd

Base iso

Seismic isoflexibility a

foundation

America in

aCorrespondin

lfth East A

MIC R

DCFP

12MS

ave friction pe

wo sliding su

ng DCFP syst

rential equatio

base-isolated

r bi-linear on

the ground

It is demonstra

to about 48 p

ones that reac

lished by Els

ble concave fric

ction

lation system

lation is thend energy d

and the supe

1985 (Zaya

g author: arashh

ia-Pacific

SPONS

EARIN

F.KHOS

ssociate ProfesC in Civil Engin

ndulum (DCF

faces. In the

ems considerin

of motion, a

structures und

are scrutiniz

otion, and fr

ted that tri-line

rcent. Howev

to 57%.

vier Ltd.

tion pendulum (

s are new d

separation ofissipation ca

rstructure. T

et al. 1987

[email protected]

onference

OF BA

S WIT

BEH

NOUDI

or, Amirkabir Uering, Amirkabi

) system is t

current paper,

g tri-linear an

computer prog

er earthquake

d by studyin

iction coeffici

ar DCFP beari

r, tri-linear D

CFP), tri-linear

vices that ar

structures frability throu

e first base

). Isolators a

on Structu

SE-ISO

TRI-LI

VIORS

N1, A.H

niversity of TechUniversity of T

e new develo

the seismic r

bi-linear beh

ram has been

excitations.

the effect of

ent of the su

gs, in compari

FP bearings c

, bi-linear, isolat

e used to pr

m the injurigh the insert

isolated stru

re classified

al Enginee

ATED S

NEAR

MMATI2a

ology, Tehran,chnology, Tehra

ed kind of fri

sponse of thr

aviors have in

eveloped in o

dvantages an

main parame

faces on the

son with bi-lin

use bigger dis

ion period, radiu

tect structur

us motion oion of so-ca

ture was bui

in two majo

ing and C

RUCT

ND BI-

rann, Iran

ction pendulu

ee dimensiona

estigated. Aft

der to obtain t

disadvantag

ers such as is

peak response

ear bearings, c

lacements of

s of curvature, f

es against se

f the groundled isolators

lt in the Uni

r groups: ela

nstruction

RES

INEAR

systems tha

l base-isolate

er deriving the

he time histor

s of tri-linea

olation period,

s under seven

an decrease the

liding surfaces

iction coefficien

ismic hazard.

by providinbetween th

ited States o

stomeric and

.

18777058 2011 Published by Elsevier Ltd.

doi:10.1016/j.proeng.2011.07.381

Procedia Engineering 14 (2011) 30273035


2/9

3028 F. KHOSHNOUDIAN and A. HEMMATI / Procedia Engineering 14 (2011) 30273035

frictional is

are usually

dissipation

Figure 1. C

The frict

curvature to

(Figure 1(a)similar to F

introducing

buildings in

(2007) studi

strong moti

in the range

there is not

previous in

components

components

behaviors a

and tri-linea

2. Mathe

Governin

of all, the

examined.

be describe

x x

NF u

R=

y yNF uR

=

Where

on the bear

depends on

solving the

lators. Fricti

composed

ystem (Soon

ross section of: (

ion pendulu

make the res

). Double coPS system wi

a second sli

Japan (Hya

ed the advant

ns. They co

of 15% -40

any special s

estigations

of earthquak

of ground m

d attempt is

r DCFPs.

atical mod

g equations

overning eq

he force disp

by (Park et

xNZ+

yNZ+

xand

yF are

ing, R is th

relative veloc

ollowing dif

nal isolators

f Polytetrafl

and Consta

) FPS; and (b)

system (FP

toring force

ncave frictioth two slidin

ing surface

uda et al. 2

ages of tri-lin

cluded that t

over bi-lin

tudy on the s

ere almost

es. Therefore

otions on the

to made co

lling of DCF

f the concav

ations of F

lacement rela

l. 1986; Con

the resisting

radius of c

ity of bearing

erential matri

use velocity

uoroethylene

tinou 1992).

CFP systems

) is a sliding

rom the pend

pendulum (surfaces. Th

as shown in

01) and a b

ear DCFP ov

i-linear DCF

ar DCFP. Th

tructures isol

for isolated

the present i

isolated struc

parison betw

P

friction pen

S bearing w

tionships of F

tantinou et a

forces ,xu an

rvature of sl

s. In these rel

x as : (Park e

ependent fric

(PTFE) and

type seismic

ulum action

CFP) systee behavior o

Figure 1(b).

idge in Can

er the bi-line

causes redu

eir investigat

ted with bi-l

structures wi

nvestigation i

ture using D

een the beha

ulum (FPS)

ill be explai

PS bearings

. 1990):

yu are bea

liding surfac

ationsx

Z ant al. 1986; Co

tion between

a stainless

isolation sys

f the weight

is a newlyan FPS can

DCFP syste

da (Constant

r DCFP for i

ction effect o

ion was perf

inear and tri-l

h DCFP un

s performed

FP bearings

ior of isolat

are very simil

ed and then

ndergoing bi

ing displace

s, is the

yZ can be anstantinou et

composite m

steel plate

tem which u

of the structu

developed debe made mor

has been u

nou 2004).

olating of the

the base sh

rmed only fo

inear DCFP

er one or t

o study the

ith bi-linear

d structures

ar to DCFPs

DCFPs equ

-directional e

ents,Nis th

oefficient of

pproximately

al. 1990):

aterials whic

s its energ

es its surfac

re on the FP

vice which ie effective b

sed in a fe

im and Yun

bridges fro

ar of the pie

r bridges an

bearings. Th

o horizontal

ffect of thre

and tri-linea

with bi-linea

ones. So firs

tions will b

xcitations can

(1

(2

e normal loa

friction tha

expressed by


3/9

F. KHOSHNOUDIAN and A. HEMMATI / Procedia Engineering 14 (2011) 30273035 3029

x

y

Z Y

Z Y

=

&

&

A , a

coefficientsequation (M

maxf=

Where fsliding frict

parameter c

The prev

to FPS equ

and therefo

with a small

3. Modeli

An appr

model of is

shows the a

subjected to

Figure 2: Ideal

4. Tri-lin

When sli

on both sur

behavior is

2x x

y x

u Z

u Z Z

&

&

d are dim

of FPS areokha et al. 1

max min( )f f

maxis the ma

ion coefficie

ontrolling the

ious equation

tions, but the

e by definin

point mass (

ng of base-is

priate model

lated buildin

ssumed struct

three compo

ized there-dimen

ar and Bi-li

ding surfaces

faces over th

so called bi-l

( sgn( )

( sgn(

x x

x x

u Z

u Z

&

&

nsionless var

modeled as88; Constanti

exp( )a u &

ximum slidin

t at essential

variation of s

s are valid fo

behavior of

two separat

1m ) represen

lated struct

needed for m

consists of

ural system

ents of earth

sional single-stor

ear DCFP b

with equal fr

e entire ran

inear like tha

2

)

)

x y

y

Z Z

Z

+

+

iables that co

the velocitynou 2004):

g friction coe

ly zero slidin

liding velocit

the friction

DCFP can be

e single conc

ting the artic

res

odeling of str

linear elastic

hich is an id

uake and m

y structure moun

earings

iction coeffici

e of motion,

of the tradit

( sgn(

sgn( )

y y

y y

u Z

u Z

&

&

ntrol the sha

dependent c

fficient at hig

g velocity; u&y coefficient.

endulum sys

modeled usi

ave FP elem

lated slider, t

uctures moun

superstructu

ealized three

unted on a D

ted on DCFP sy

ient are used

regardless o

ional FPS (C

)

)

x

y

u

u

+

+

&

&

e of the hyst

efficients of

h sliding vel

is the total

tem (FPS). D

g two FP lin

nts and then

he overall be

ted on DCFP

e and a nonli

dimensional

CFP bearing.

tem

2 1= ), tf the radii o

onstantaniou

retic loop. Sl

friction as t

city;minf is

liding veloci

CFPs equatio

k elements a

connecting t

avior of DC

bearings. In t

near base isol

ingle story b

ere is simulta

curvature.

004). Durin

(3

liding friction

he followin

(4

the minimu

y and a is

ns are simila

ting in serie

hem in serie

P is obtained

his study, th

ator. Figure 2

ilding model

neous slidin

he hysteretic

this regime,

.


4/9


the isolatio

loops of bi-l

2comb

T =

11 2

RT

g=

1Tan

Figure 3: T

When fri

motion initi

During this

After the dihigher fricti

regime, the

and*u are

1 1(eq

R =

*

2(u =

Based on

of three co

bi-linear an

5. Verific

The accu

with the res

al. (1998).

period (iT)

inear DCFP

1 2R R

g

+=

,2 2T =

2T are restor

e hysteretic c

ction coeffic

tes on the su

sliding regi

placement eon and moti

isolation peri

assumed by f

1 2 2

1 2 1

) (h R

R h

+

+

1 1 1)( )R h

above equat

ponents of e

tri-linear be

ation

racy of devel

ults derived f

heir structur

can be descri

nd tri-linear

2 2

1 2T T+

2R

g

ing periods o

urve of: (a) b

ient is differ

rface of least

e, the isolati

ceeds

*

u , thon continues

od is equal t

llowing equ

2

2

)h

ions, a comp

arthquakes o

aviors.

oped progra

rom two pap

l model was

bed by Eqn

CFP.

f the lower an

i-linear DCF

nt on the up

friction coeff

on period eq

re is sufficiewith simulta

ocombT . Fo

tions (Consta

ter program

the respons

was verifie

rs performed

3D single st

(Kim and

d upper slidi

(b) tri-linear

per and low

icient and co

als to 1Tfor

t horizontalneous slidin

r tri-linear D

ntaniou 2004

was written

e of isolated

by compari

by Khoshno

ory building,

un 2007). Fi

g surfaces in

DCFP

r concave sl

tinues on thi

1 2< an

force to initia on both sli

CFPs, an eq

):

sing MATL

structures res

g the result

dian and Ra

similar to the

ure 3 illustr

the same ord

iding surface

surface for a

equals to T

te sliding oning surfaces

ivalent fricti

B to investi

ing on DCF

btained fro

iei (2010) an

Figure 2.

tes hysteretic

(5

(6

r.

s ( 2 1 ),

distance*u .

2 for 1 2 > .

the surface o. During thi

n coefficien

(7

(8

ate the effec

system with

the progra

d Almazan e


5/9


Almazan

Their struct

throughout

of the FP b

to be the sa

mentioned i

min maf f=

Figure 4: Com

directions unde

In these

results dem

6. Numer

The resp

bearing sub

structures a

the superstr

current stud

considered

Turkey Duzand Northri

In this st

motion are

bearings hy

structure re

et al . (1998

ural model

he study, the

aring using t

e and equal

nvestigation,

20.07, m=

arison of hyster

r Northridge eart

igures, the b

nstrated the

ical study

onse of three

jected to thr

e the base sh

cture is assu

y, seven eart

nd applied t

ce (1999), Tge (1994).

udy, the fricti

considered a

steretic beha

ting on DCF

investigated

as a 3D si

friction coef

he developed

to the half o

the followin

3/ 0.2,m =

tic curves obtai

hquake

aring displac

alidity of the

dimensional

ee compone

ar of superst

med to be 2

quake recor

the isolated

rkey Erzinca

on coefficien

the variable

vior, bi-linea

bearings.

the respons

gle story bu

icient of the

program, the

radius curva

parameters0.5s Sec=

ed from: (a) Al

ements are n

program.

single story

ts of earthq

ucture and th

of critical d

s with differ

structure. T

n (1992), Ko

t of sliding s

parameters

r and tri-lin

of FP base

ilding, simil

liding was k

radius of the

ure of FP be

are used for.

azan et al. (199

rmalized by

building rest

uakes has b

e relative bea

amping. The

ent sources,

ese earthqua

e (1995), N

urfaces, isola

nd attempt i

ar DCFPs o

isolated stru

r to Figure

pt constant a

upper and lo

ring (Consta

odeling the

) (b) Developed

bearing radii

ing on the tr

en studied.

ring displace

ime step was

echanisms, i

e records ar

rthridge (199

ion period (

s made to ex

n the earthq

tures using

, with a FP

d equal to 0.

wer concave

tinou 2004).

FP base-isola

computer progra

of curvature.

i-linear or bi

he response

ent. The da

chosen 0.00

ntensities an

Cape Mend

4), N.Palm S

i ) and intens

amine the ef

uake respons

arious FPSs.

bearing and

07. To model

are assumed

Based on th

ted structure:

min x and y

The obtained

-linear DCFP

s of isolated

ping ratio o

1 Sec. For th

duration ar

ocino (1992),

prings (1986

ity of ground

ect of DCFP

e of isolated


6/9


6.1 Bi-linea

In this se

sliding surf

from 0.1 to

high slidingof sliding s

isolation pe

motions.

6.1.1. Isola

In this se

structure re

difference o

DCFP has

vertical ax

max 2 maxf feach record

is kept cons

The maxim

coefficients

friction coe

value of dif

displaceme

isolation pe

isolation, th

to increasin

and lower sl

Figure 5: The

Figure 6

the base sh

and Tri-line

ction, variou

ces are supp

0.17. During

velocity andurfaces are a

riod, differen

tion period

ction attempt

ponses restin

fmax2f and f

i-linear beha

shows th

1 0= . Respoare the maxi

ant and is eq

um bearing

of sliding su

ficient of sli

erence of fri

t increases.

riod is diffe

e increasing

in the isolat

iding surface

aximum bearin

shows the inf

ar with varia

ar DCFPs

DCFPs are

sed to be var

this variation

0.03 for zerossumed to b

ces of fricti

is made to e

g on bi-linear

ax1(

max2f fvior and for

values of

ses are obtai

um value of

al to 0.5 Sec

isplacement

rfaces are ill

ding surfaces

tion coeffici

he growing

ent. This fi

ercentage of

ion period an

s.

displacement i

luence of inc

ion of the is

ssumed and

iable.max1f d

, equivalent

sliding veloc the same. S

n coefficient

amine the ef

or tri-linear

ax1) which is

another value

the respons

ned from av

response duri

and the isolat

in x and y d

strated in Fi

increases, th

nt increases,

ercentage of

ure clearly i

bearing displ

d also increa

x and y directio

ease in the di

lation period

or having tri-

ecreases fro

riction coeffi

ity ( max eqf =ome analyze

s of sliding

ects of chan

CFPs. In ne

increased fr

ofmax2f

es which is

rage of the s

ing time histo

ion period (

irections duri

ure 5. As th

e bearing dis

the amount o

the bearing

ndicates the

acement gro

ing of differ

ns

fferences of

. As the figu

linear and bi-

0.1 to 0.03 a

cients are kep

min0.1, eqf =s are perfor

urfaces and

es in the isol

t figures the

m zero to 0.

max1, DCFP h

normalized

even records.

ry analysis.

i) varies fro

ng increasin

e figure depi

placement in

f*

u grows uisplacement

fact that in

s up. The re

nces of the f

riction coeffi

e illustrates,

linear DCFP

nd inverse ft constant an

.03 ). In addied for differ

also magnitu

tion period o

horizontal ax

14. Whenmaf

as tri-linear

to the res

In addition,

he period of

2 to 5 sec.

in differenc

ts, when the

reases. Beca

and therefo

ith various

he upper pe

son of this f

iction coeffi

cient of slidin

hen differen

,maxf of tw

ax 2increase

d equal 0.1 a

tion, the radiient values o

de of ground

n the isolated

e presents th

x 2 max1 0f = ,

ehavior. Th

onses whe

responses fo

structure (sT

es of friction

difference o

use when th

re the bearin

mount of th

riods of bas

ct are related

ient of uppe

g surfaces on

ce of friction


7/9


coefficient

differences

Because in

base isolato

isolation, th

concluded tthe same co

Figure 6: The

6.1.2. Ampli

In this s

amplitude o

system is in

to 4 and 0.bearing dis

increases, t

earthquake

Figure 7: The

f sliding sur

in bearing co

the lower iso

r works far

e effect of

at the base snditions.

aximum base s

tude of the gr

ction, the sel

f ground mot

vestigated. T

5 Sec respeclacement. T

he bearing

ecords.

aximum bearin

faces increas

efficient of f

lation period

rom its real

ifferences o

ear in isolat

ear in x and y di

ound motion

cted records

ions on the r

e isolation p

ively. Figurhe figure sh

isplacement

displacement in

s, the base s

iction in the

, the structur

behavior. Co

friction coe

d structure w

rections

are scaled to

sponse of iso

riod and the

7 depicts thws as the d

grows up a

x and y directio

hear decreas

lower isolati

e period is cl

ntrary to the

fficient on t

ith tri-linear

three values

lated structur

superstructur

e influenceifference of

nd this incr

ns

s. According

n period is i

ose to the is

previous res

e base shea

CFP is less

(0.5, 0.7 and

e resting on

e period are a

f amplitudefriction coef

asing is les

to the figure

nsignificant (

lation period

lt, in the up

is remarkab

han bi-linear

0.9) g and th

i-linear or tri

ssumed const

of ground mficient of sli

s significant

the effect o

2,3seci

T = ).and thus th

per period o

le. It can b

DCFP one in

effect of th

-linear DCFP

ant and equal

otions on thding surface

for stronge


8/9


Figure 8

various am

coefficient

on the ampli

Figure 8: The

7. Conclu

The resul

1. A cha

bearin

2. The b

consist

signifi

this st3. The b

especi

defor

excitat

References

[1] Almaza

Earthqu

[2] Consta

report

[3] Consta

http://w

[4] Hyakud

structu

the 7th

Assisi,

presents the

litudes of g

f friction cau

itude of grou

aximum base s

sions

ts of this stud

ge in DCFP

displaceme

se shear for

ently smaller

ant values o

dy is 48% relaring displa

lly for the

ations reach

ions.

n, J.L., De la lle

ake Engineering

tinou MC, Tsop

CEER-99-0012.

tinou, M.C..

ww.studenthere.

a, T., Saito, K.,

al design and ea

International Se

Italy, October; 2

effect of dif

ound motion

ses the decre

d motions.

ear in x and y di

y are summa

earing behav

ts, but a decr

ces of isolat

than bi-linea

the base iso

ated to the bcements of t

eak earthqua

to 57% in

a, J.c. and Inaud

and Structural

elas P ,Kasalanti

. Buffalo (NY):

Friction P

om/redirect.php

Matsushita, T., T

rthquake observ

inar on Seismic

01.

erences in th

. According

ase in base sh

rections

ized as follo

ior from bi-li

ease in the ba

d structures

r DCFP one,

lation period.

se shear.he tri-linear

kes and uppe

pper values

i, J.A. "Modelin

ynamics, Vol.27

A, Wolf DE. Pr

ational Center f

ndulum Doub

?url=http://nees.

anaka, N., Yone

tion of a seismic

Isolation, Passiv

e bearing co

to this figur

ear. The max

s:

near to tri-lin

se shear.

resting on tr

particularly

The maxim

DCFPs are l

r values of t

of the isolati

aspects of struc

, No. 8; 1998, pp

perty modificati

r Earthquake En

le Concave

uffalo.edu/dec3

ki, S., Yasuda,

isolation bearin

e Energy Dissip

fficient of fri

, increase o

imum of decr

ar generally

i-linear DCF

or low ampli

m decrease

arger than t

e base isolat

on period a

tures isolated wit

. 845-867.

on factors for sei

gineering Resear

Bearing, NE

4/FP-DC%20R

., Miyazaki, M.,

g using friction

tion and Active

ction on the

difference i

easing perce

esults in an i

system are

ude of groun

f the respons

ose of the

ion period. T

d under wea

h the frictional p

smic isolation be

ch; 1990

ES Report,

port-DEMO.pdf

Suzuki, A. and

endulum system

Control of Vibra

base shear in

the bearin

tage depend

ncrease in th

found to b

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e recorded in

i-linear one

he additional

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endulum system"

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Available at:

; 2004.

Sawada, T.. "Th

", Proceedings o

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,

l

:

,


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with tri-linear behavior", Engineering Structures, Vol. 29, No. 11; 2007, pp. 3082-3093.

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J.Earthquake Engineering and Structural Dynamics, 14;1986, pp.543-557.

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On earthq. Disaster reduction technol. 30th anniv. Of IISEE; 1992, p. 455-69.

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seismic reponse of structures using dcfp bearings with tri-linear and bi-linear behaviours

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