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�2|xQwO uQ=kDt=v |xk@]l} |=yu=tDN=U VJ}B pQDvm

|m =m]Y= |=yQo =Q}t \UwD |tQH�OWQ= |U=vWQ� |wHWv=O� |}wRQ@ u}Or=p=tH

�Q=}O=DU=� ?sOktOkwQU =[Qr=O@axrRrR |UOvyt w |U=vWxrRrR |rrtr=u}@ x=oWywSB

|=yxR=U VJ}B pQDvm QO |m =m]Y= |=yQo =Q}t C@Ft OQmrta R= |m =L xDWPo C=ar=]tVJ}B pQDvm QO =yu; Q=Okt w QF-wt |=yQDt=Q=B u}}aD xar=]t u}= R= hOy "CU= uQ=kDt=v

|=yu=tDN=U Qw_vt u}= |=Q@ "CU= |m =m]Y= |=yQo =Q}t \UwD |tQH uQ=kDt=v |xR=U'|tQH hrDNt |=yC} RmQt R= GwQN |=R=x@ w x}=B uQ=kDt pOt l} T=U=Q@ |Oqwi

Qo =Q}t x@ pYDt |=yOv@ Q=yt w |m =m]Y= Qo =Q}t C=YNWt w Qo =Q}t hrDNt |=y`} RwD|=yMU=B "Ov=xDiQo Q=Qk p}rLD OQwt w xOW pOt OpenSees Q=Ri=sQv \UwD |m =m]Y=

|=yQDt=Q=B w Ov=xOW xU}=kt `} RwD hrDNt Cq=L |=Q@ Qo =Q}t x@ RyHt u=tDN=U R= pY=L|WRer Q=@ '=yQo =Q}t |Q}oQ=Qk C}a[w |xv}y@ Cq=L Q}_v Q=DiQ QO =yu; Q=Okt w QF-wtxDiQo Q=Qk xar=]t OQwt |m =m]Y= Qo =Q}t x@ pYDt Ov@ Q=yt '|m =m]Y= Qo =Q}t |xv}y@

QO xv}y@ Cr=L QO xOWQmP |=yQDt=Q=B xJv=vJ CiQo xH}Dv u=wD|t C}=yv QO "CU=VJ}B pQDvm |}=v=wD |m =m]Y= |=yQo =Q}t 'OQ}o Q=Qk xO=iDU= OQwt uQ=kDt=v |xR=U

"OvQ=O =Q uQ=kDt=v |=yxR=U |wk w h}a[

a.borzouie@iiees.ac.ira.sarvghad.moghadam@gmail.com

Qo =Q}t '|SQv= lqyDU= 'uQ=kDt=v u=tDN=U 'xR=U VJ}B %|O}rm u=oS=w"|tQH C} RmQt R= GwQN '|m =m]Y=

xtOkt "1|iQat |Oqwi |=yjQw u}@ |SQv= lqyDU= Q@ |vD@t *Q=OQ=}W w Q=OI}B Cq=YD=Q@ |vD@t *OQmrta =@ |m =m]Y= Qo =Q}t R= |O}OH wv 2000 p=U QO [3]"OW

[4]"OW |iQat p=YD= CtUk QO Ov@ Q=yt *u=QwO R= pY=L l =m]Y==D Ov@ Q=yt R= pY=L |DNU p}rOx@ |m =m]Y= |=yQo =Q}t x@ RyHt |=yxR=U|=yxrRrR QO 'u; R= Oa@ |SQv= lqyDU= w |m =m]Y= |=yQo =Q}t QO VRer R= p@k'hrDNt *|m =m]Y= |=yQo =Q}t |iQat =@ "Ov=xO=O u=Wv |@U=vt OQmrta O}OW"Ci=} VQDUo |m =m]Y= Qo =Q}t x@ RyHt |xR=U |L=Q] pwY= w OQmrta |xar=]tp=U QO [5]"OvDN=OQB xR=U l} |=Q@ xv}y@ |}=Q}t u}}@D x@ u}kkLt 1993 p=U QO[6]"OW x�=Q= |m =m]Y= |=yQo =Q}t |WRer Q=@ `} QU u}tND |=Q@ |WwQ R}v 1993|=yQo =Q}t x@ RyHt |=yxR=U |L=Q] |xv}tR QO |D=ar=]t 2000 p=U QO u; R=TB|WwQ u}kkLt xt=O= QO [7]"OW s=Hv= |@v=H Q=@ VwQ R= xO=iDU= =@ '|m =m]Y=T=U=Q@ |m =m]Y= |=yQo =Q}t |xr}Uwx@ xOW |Ov@ Q=yt |=y?=k |L=Q] |=Q@|R=Uy@ |=Q@ |WwQ 2006 p=U QO u}vJty [8]"OvOQm x�=Q= xrRrR hrDNt |=yOQwmQ[9]"OW KQ]t QN; |xk@] |}=Hx@=H T=U=Q@ |m =m]Y= Qo =Q}t x@ RyHt |=yxR=UxHwD OQwt R}v uQ=kDt=v |xR=U VJ}B pQDvm |=Q@ |m =m]Y= Qo =Q}t OQ@ Q=m|xv}tR QO |D=ar=]t 2000 w 1991 |=yp=U QO "CU= xOw@ u}kkLt R= |O=OaD

|Q}tNQ}e w |Q}tN |=ypmW Q}}eD RmQtD R= u=Wv xDWPo |=yxrRrR R= pY=L G}=DvOQmrta Ow@y@ |=Q@ =yxt=vu}}; pL x=Q "OQ=O uQ=kDt=v |xR=U |=[a= R= |O=OaD QOV}=Ri= |=Q@ |}xR=U |=[a= Ctw=kt w |DNU Q}}eD Q@ |vD@t uQ=kDt=v |=yxR=URmQtD x@ xHwD =@ [1]"CU= xrRrR QO VJ}B R= pY=L |=ywQ}v Q@=Q@ QO u; C}iQ_u}= w OvUQ|t s}rUD x@ QDOwR x@r u}= QO `k=w |=[a= 'sQv |x@r QO =ypmW Q}}eD"OwW|t CNU |x@r CtU x@ Ctw=kt w |DNU C} RmQt R= GwQN V}=Ri= Ea=@RmQt xm so =Qi=}O R= |}x@r "OwW|t xDU=m jwi VwQ Q=@Da= R= =yxrRrR QO u}=Q@=v@u=wvax@ p@=kt |x@r w �sQv |x@r� u=wvax@ OQ=O Q=Qk u=QwO RmQt w x@r u; u}@ sQH|=yxOvvmlryDUt R= xO=iDU= 'Qo}O VwQ =t= "OwW|t |Q=Pos=v �CNU |x@r�uQ=kDt=v |=yxR=U QO |WJ}B pO=aD |=Q@ �� |m =m]Y= |=yQo =Q}t Q}_v �� |SQv=

"CU=|m =m]Y= |=yQo =Q}t `=wv= CN=U '1982 p=U QO Qo =Q}t u}rw= |iQat R= Oa@1989 p=U QO [2]"Ci=} uwRi=RwQ VQDUo xR=U OQmrta Ow@y@ QO =yu; OQ@ Q=m w

pw�Ut xOvU} wv ?"1389 10 27 VQ}PB '1389 5 18 x}LqY= '1388 5 14 Ci=} QO %M} Q=D

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DOI 10.7603/s40354-012-0002-9

"""|tQH

uQ=kDt=v

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J}BpQDv

m

"|tQH C} RmQt R= GwQN =@ xR=U uqB "2 pmW

`} RwD uqB QO � |L]U |r=oJ =@ CN=wvm} Qw]x@ xR=U sQH CUNv OwW|txR=U CU=Q CtU QO XNWt ZQa =@ |Q=wv |L]U |r=oJ TBU w CU= xOW'O@=}|t Vy=m u=R}t u=tyx@ u; p@=kt *CtU QO Q=wv |L]U |r=oJ w xDi=} V}=Ri=b w 'x CyH QO a O=a@= x@ xR=U uqB "Ov=t|t |k=@ C@=F uqB pm sQH xm |}xvwox@

"CU= Q_v Ot � |tQH |r=oJ =@ 2 pmW j@=]t y CyH QOQO |L]U *|r=oJ *Q=Okt w 'xOW xDiQo Q_v QO K]U RmQt QO C=YDNt -=O@t�(1 + �) Q@=Q@ �� xR=U CU=Q CtU QO �� (0 < � < 0 5)�a ZQax@ |Q=wvCQ=@a \@=wQ u}= QO "OwW|t ZQi �(1 � �) Q@=Q@ u; p@=kt *CtU *Q=wv QO wQ=Okt Cr=L u}= QO "CU= |r=oJ V}=Ri= Q=Okt Qou=Wv (�1 < � < 1)�

"CU= 1 |xrO=at j@=]t C=YDNt RmQt x@ C@Uv xOW xR}r=tQv C} RmQt R= GwQNw � = �1 |=R=x@ 1 |xrO=at R= |Q}ojDWt =@ |tQH C} RmQt R= GwQN xv}W}@R= GwQN T=U=Q@ uQ=kDt=v |=ypOt "OW Oy=wN em = �0 25 Q@=Q@ � = 0 5QO xO=iDU= OQwt |=ypOt C=YNWt "Ov=xOW O=H}= -X CyH QO |tQH C} RmQt?w=vD u=tR Ty '|tQH C} RmQt R= GwQN em pwOH u}= QO "CU= xOt; 1 pwOH=@ "CU= xR=U swO w pw= ?w=vD u=tR T1; T2 w |WJ}B ?w=vD u=tR T� '|@v=H

"Ov=|WJ}B CNU =ypOt s=tD xm s}@=}|tQO T� w Ty |xU}=kt[16]%CU= 3 w 2 |xrO=at j@=]t x} wv=F sQH RmQt pwL |UQv}= u=tt Q=Okt

em = 1a �(1 + �)�ab� (a2 � �a

2 ) + �(1� �)�ab� (�a2 + �a2 )

�ab

!= ��(1� �) (1)

ICM = I1CM + I2CM + I3CM (2)

ICM = M1

"��2a2 + b2

�12 + (a2 �

�a2 + aem)2

#+M2

�(a� 2�a)2 + b2

12 + a2e2m

�+M3

"��2a2 + b2

�12 + (a2 �

�a2 � aem)2

#(3)

2 '1 |=yVN@ |tQH |UQv}= u=tt ?}DQDx@ I3CM w I2CM w I1CM u; QO xmu=Wv xar=]t OQwt |xR=U |=Q@ em ?ULQ@ =Q ICM C=Q}}eD 3 pmW "CU= 3 w

"CU= � R= pkDUt ICM xm OwW|t Qw;O=} "OyO|t

u; G}=Dv xm OW s=Hv= |m =m]Y= Qo =Q}t |xr}Uwx@ uQ=kDt=v |xR=U VJ}B pQDvmR}v 2005 p=U QO [11w10]"OW xv}y@ |WRer Q=@ w Qo =Q}t |xv}y@ u=mt |x�=Q= x@ QHvt|m =m]Y= |=yQo =Q}t R= xO=iDU= =@ uQ=kDt=v |xR=U VJ}B pQDvm uwt=Q}B |D=ar=]t|xR=U OQmrta *?U=vt XN=W u=wvax@ |@ QHD pO=aD RmQt |iQat x@ xm OW s=Hv=[1]"OW QHvt |@ QHD pO=aD RmQt |xv}y@ u=mt |UQQ@ w |m =m]Y= Qo =Q}t x@ RyHtxm 'uQ=kDt=v |xR=U VJ}B pQDvm x@ \w@ Qt C=ar=]t |xt=O= QO xar=]t u}=xOW s=Hv= 'xOW VQ=Ro |DNU C} RmQt R= GwQN =@ |=yxR=U |xv}tR QO QDV}Bx@ pYDt |=yOv@ Q=yt w |m =m]Y= |=yQo =Q}t OQmrta xar=]t u}= QO [12]"CU=|UQQ@ OQwt |tQH uQ=kDt=v |=yxR=U |WJ}B pO=aD QO |m =m]Y= |=yQo =Q}t'Cw=iDt |WRer |=yQ=@ =@ |m =m]Y= |=yQo =Q}t Qw_vt u}= |=Q@ "CU= xDiQo Q=Qk|m =m]Y= |=yQo =Q}t x@pYDt *hrDNt |=yOv@ Q=yt|DNU w 'hrDNt |=yu=tO}J�� hrDNt |tQH |=yC} RmQt R= GwQN =@ uQ=kDt=v |xR=U VJ}B pQDvm Qw_vtx@ ��CLD |]NQ}e |v=tR |xJN} Q=D *p}rLD OpenSees |xt=vQ@ \UwD w xOW xi=[=w |WRer Q=@ C}=yv QO [13]"CU= xOW s=Hv= =yu; |wQ Q@ hrDNt |xrRrR CiypYDt |=yOv@ Q=yt |xv}y@ |DNU w |m =m]Y= |=yQo =Q}t |xv}y@ |WRer Q=@ RmQtR= GwQN =@ xR=U |wk w h}a[ |WJ}B pO=aD |=Q@ |m =m]Y= |=yQo =Q}t x@

"CU= xDiQo Q=Qk |UQQ@ OQwt Cw=iDt |tQH |=yC} RmQt

|r}rLD |=ypOt "2x}=B uQ=kDt pOt "1"2

|m =m]Y= Qo =Q}t x@ RyHt Ov@ Q=yt =@ |WtN ?=k |Oqwi |xR=U xar=]t u}= QOxDiQo Q=Qk |UQQ@ OQwt OQ=O xv=yO 3 =DU=Q Qy QO xm QDt 3 3 `=iDQ=x@ |}xk@] QO

"�1 pmW� CU=w u=Q}= Oqwi |xt=vu}}; T=U=Q@ \UwDt |WtN ?=k CQwYx@ x}rw= |xR=U|@Uv Q]N |xvyB =@ |}xk]vt QO uQ=kDt Cr=L |=Q@ u=Q}= |xrRrR 2800 |xt=vu}};xOW |L=Q] (Ts = 0 5 sec) CNU l =N w (A = 0 35 g) O=} R Q=}U@x@ RyHt |=ysDU}U |=Q@ x}=B VQ@ Vy=m \@=w[ R= |L=Q] u}= QO [14]"CU=

[15]"CU= xOW xO=iDU= FEMA450�2003� |xt=vu}}; T=U=Q@ Qo =Q}t

uQ=kDt=v |=ypOt "2"2RmQt x@ C@Uv xR=U sQH RmQt |}=Hx@=H '|tQH C} RmQt R= GwQN O=H}= Qw_vtx@ZQi y QwLt pwL |tQH |vQ=kDt=v O=H}= |=Q@ j}kLD u}= QO "CU= |QwQ[ K]U

"xar=]t OQwt |xR=U uqB "1 pmW

10

sOktOkwQ

U=[Qr=O@

aw|}w

RQ@u}Or=p

=tH "6 =D 1 |=ypOt C=YNWt "1 pwOH

T2 (sec) T1 (sec)T� (sec) Ty (sec) uOW |Q=H Ctw=kt �em pOt xQ=tW

(xDU@tyQ}e) (xDU@tyQ}e) (ton)

0 296 0 389 0 298 0 384 152 8 �5 0 10 287 0 403 0 295 0 384 152 8 �10 0 20 277 0 421 0 29 0 384 152 8 �15 0 30 266 0 443 0 284 0 384 152 8 �20 0 40 256 0 468 0 277 0 384 152 8 �25 0 5

|m =m]Y= |=yQo =Q}t Q=QkDU= |=Q@ VwQ Q=yJ '|WRer Q=@ C} RmQt R= GwQN%OW QwYDt u=wD|t 1 pmW QO xOW xO=O u=Wv |xR=U QO

QO ?=k =yvD Cr=L u}= QO xm �50 |WRer Q=@ C} RmQt R= GwQN |=Q@ �hr=&CU= |m =m]Y= Qo =Q}t x@ RyHt D |=DU=Q

|=y?=k Cr=L u}= QO xm �50 =D �38 |WRer Q=@ C} RmQt R= GwQN |=Q@ �?&CU= |m =m]Y= Qo =Q}t x@ RyHt C;D |=DU=Q QO

|=y?=k Cr=L u}= QO xm �38 =D �27 |WRer Q=@ C} RmQt R= GwQN |=Q@ �G&CU= |m =m]Y= Qo =Q}t x@ RyHt B;C;D |=DU=Q QO

|=y?=k Cr=L u}= QO xm �38 =D �0 |WRer Q=@ C} RmQt R= GwQN |=Q@ �O"CU= |m =m]Y= Qo =Q}t x@ RyHt A;B;C;D |=DU=Q QO

u}@ |WRer Q=@ RmQt '|m =m]Y= Qo =Q}t OQmrta |UQQ@ Qw_vt x@CU= Q@=Q@ xrLQt Qy QO |WRer Q=@ RmQt "Ovm|t Q}}eD �0 5D � ed � +0 5D

%=@ed = 1P

SLi

4Xi=1

SLi �Xi!

(4)

|m =m]Y= Qo =Q}t |xrY=iX w �uD�|m =m]Y= Qo =Q}t|WRer Q=@ Q@=Q@ SL u; QO xm|=yQo =Q}t `} RwD u}= Q@=v@ "CU= X CyH QO �QDt� xR=U Oa@D w K]U RmQt w �QDt�Q=@ 'xrLQt Qy QO 4 pmW x@ xHwD =@ "OwW|t xDiQo Q_v QO 4 pmW j@=]t|m =m]Y=QO w O@=}|t X=YDN= xR=U pm|@v=HCtw=kt R= |OYQO T=U=Q@ 1 Qo =Q}t|WRer�ed = 0 055D |=ys=o =@ �0 5D � ed � +0 5D |=R=x@ Oa@ |xrLQt"O@=}|t Q}}eD 4 w 3 '2 |xQ=tW |=yQo =Q}t |WRer Q=@ xH}DvQO w |WRer Q=@ RmQtIV CtUk QO xm QDt �4 |WRer Q=@ C} RmQt R= GwQN Cr=L QO p=Ft u=wvax@`} RwD ZQi =@ w CU= |m =m]Y= Qo =Q}t x@ RyHt =yxv=yO s=tD 'OQ}o|t Q=Qk 4 pmW'uD 10 pO=at |xv}W}@ |WRer Q=@ w |m =m]Y= |=yQo =Q}t u}@ |WRer Q=@ |]N

"CU= 5 pmW j@=]t |m =m]Y= |=yQo =Q}t u}@ |WRer Q=@ `} RwD

|m =m]Y= Qo =Q}t |R=UpOt "4"2CQwYx@ Ov@ Q=yt w |m =m]Y= Qo =Q}t CU= sRq '|m =m]Y= Qo =Q}t |R=UpOt |=Q@|DNU '|m =m]Y= Qo =Q}t VRer R= p@k =D "OwW xDiQo Q_v QO |@}mQD u=tr= l}"CU= QiY wtHt |DNU 'VRer R= Oa@ "CU= Ov@ Q=yt |DNU Q@=Q@ pm *u=tr=Q=@ R= QDsm Cr=L u} QDW}@ QO Qo =Q}t QO |WRer Q=@ xm u}= x@ xHwD =@ u}vJtyQo =Q}t |WRer Q=@ Q@=Q@ |]NwO u=tr= u}= s}rUD |x]kv 'xOW ZQi Ov@ Q=yt |Wv=tm

"em ?UL Q@ ICM C=Q}}eD |vLvt "3 pmW

=yQo =Q}t `} RwD "3"2"Ov=xOW xi=[= sDU}U x@ Y |=DU=Q =yOv@ Q=yt QO Q=QkDU= =@ |m =m]Y= |=yQo =Q}t

%R= CU= CQ=@a hrDNt |=ypOt u}@ =yQo =Q}t `} RwD |=yZQiV}B|WRer Q=@ Q=Okt QO Q}}eD Ea=@ |]}Lt C=QF= w =tO C=Q}}eD 'u=tR CWPo =@ "1|m =m]Y= |=yQo =Q}t|}=yv|WRer Q=@ u}=Q@=v@ "OwW|t��15 QFm =OL u=R}tx@

"OwW|t ZQi Ov@ Q=yt |Wv=tm Q=@ R= QDsm �15|=yQo =Q}t u}@ |WRer Q=@ `} RwD '|WRer Q=@ *C} RmQt R= GwQN p=ta= |=Q@ "2Q=Okt T=U=Q@ "CU= xOW ZQi |]N CQwYx@ 4 pmW j@=]t |m =m]Y=

Q=@ |]N `} RwD ZQi =@ |WRer Q=@ RmQt u=mt T=U=Q@ =yQo =Q}t `} RwD "4 pmW"|m =m]Y= |=yQo =Q}t u}@ |WRer

11

"""|tQH

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m�NEHRP C=YNWt j@]� B wv CNU l =N |wQ Q@ w xOw@ 1pUo R= QwO wv"Ov=xOW CW=OQ@

p}rLD G}=Dv "3OQwt 1 pwOH j@] 5 =D 1 |=ypOt '|m =m]Y= Qo =Q}t OQmrta |UQQ@ |=Q@19� QDt �9 =D QDt �9 R= |WRer Q=@ RmQt pOt Qy |=Q@ "CU= xDiQo Q=Qk |UQQ@Q@=Q@ �xrLQt Qy QO |WRer Q=@ u} QDW}@� 1 Qo =Q}t |WRer Q=@ w 'Ovm|t Q}}eD �x]kv|DNU C@Uv xU =@ Ov@ Q=yt pOt Qy QO w 'xR=U pm |@v=H Ctw=kt R= |D@Uvh}a[ |WJ}B pO=aD |UQQ@ Qw_vtx@ "CU= xOW xDiQo Q_v QO ?=k x@ Ov@ Q=yt|xR=U Cr=L QO CNU w sQv |x@r u=mt Q}}eD xv}W}@ hqDN= 'uQ=kDt=v |xR=U QO�5 xrO=at� |m =m]Y= Qo =Q}t uwO@ |xR=U x@ C@Uv |m =m]Y= Qo =Q}t x@ RyHtRmQt u=QwO '|wk |WJ}B pO=aD |UQQ@ |=Q@ u}vJty &CiQo Q=Qk xar=]t OQwtQo =Q}t uwO@ |xR=U x@ C@Uv |m =m]Y= Qo =Q}t x@ RyHt |xR=U Cr=L QO |UOvyu=mt Q}}eD uright "CU= xDiQo Q=Qk |UQQ@ w p}rLD OQwt �6 xrO=at� |m =m]Y==yp}rLD "CU= |UOvy RmQt u=QwO �cm w sQv |x@r u=mt Q}}eD uleft 'CNU |x@rxrRrR Ciy u}= R= pY=L u}ov=}t xrY=L G}=Dv w xOW s=Hv= xrRrR Ciy OQwtQO

"CU=�K]U RmQt u=QwO w x@r wO u=mt Q}}eD hqDN=� xR=U |xv}y@ MU=B 7 pmW QOC} RmQt R= GwQN QO hrDNt Ov@ Q=yt |DNU w |WRer Q=@ hrDNt Q}O=kt |=Q@MU=B u} QDsm R= CU= CQ=@a xv}y@ MU=B "CU= xOW xO=O u=Wv �25 =D �5 |tQHQ=@ RmQt |=Q@ C@=F |tQH C} RmQt R= GwQN w Ov@ Q=yt |DNU '|WRer Q=@ |=Q@ xR=U

"CU= ��9m '�9m� hrDNt |WRerRATIO1 =

���jE(uleft)maxj � jE(uright)jmax

���withFD

(jjE(uleft)maxj � jE(uright)maxjj)withoutFD (5)

RATIO2 =(�cm)withFD

(�cm)withoutFD(6)

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CWwv=B1. far �eld

`@=vt1. De la lera, J.C. and et al. \Torsional balance asymmetric

structures with frictional dampers: Analytical results",Earthquake Engineering and Structural Dynamics, 34,pp. 1089-1108 (2005).

2. Pall, S. and Marsh. C. \Response of friction dampedbraced frames", Journal of Structural Engineering,108(6), pp. 1313-1323 (1982).

3. Fitzgerald, T.F. and et al. \Slotted bolted connection ina seismic design for concentrically braced connections",Earthquake Spectra, 5(2), pp.383-391 (1989).

4. Mualla, I.H., Experimental and Computational Evalua-tion of Novel Friction Damper Device, PHD Thesis Deptof Structural Engineering and Materials, Technical Uni-versity of Denmark (2000).

5. Scholl, R. \Fundamental design issues for supplementaldamping applications" Earthquake Spectra, 9(3), pp.627-636 (1993)

6. Cherry, S. and Filiatrault, A. \Seismic response controlof buildings using friction dampers", Earthquake Spectra,9(3), pp.447-466 (1993).

7. Yoamin, F.U. and Sheldon, C. \Design of frictiondamped structures using lateral force procedure", Earth-quake Engineering and Structural Dynamics, 29, pp.989-1010 (2000).

8. Levy, R.; Lavan, O. and Rutenberg, A. \Seismic de-sign of friction-damped braced frames based on historicalrecords", Earthquake Spectra, 21(3), pp. 761-778 (2005).

9. Kim, J. and Choi, H. \Displacement based design of sup-plemental dampers for seismic retro�t of a framed struc-ture", Journal of Structural Engineering, 132(6), p.p.873 (2006).

10. Pekau, O. and Grimond, R. \Controlling seismic re-sponse of eccentric structures by friction dampers",Earthquake Engineering and Structural Dynamics, 20,pp. 505-521 (1991).

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15

�References�

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16. Borzouie, J. \Control of torsional asymmetric structuresusing frictional dampers", A M.S. Thesis, (in Persian)(2009).

Abs

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TORSIONAL CONTROL OF MASSECCENTRIC ONE STORYBUILDINGS BY FRICTIONDAMPERSJ. Borzouiea.borzouie@iiees.ac.irA.S.Moghadam?

a.sarvghad.moghadam@gmail.comInternational Institute of EarthquakeEngineering and Seismology

Sharif Civil Engineering JournalVolume 28, Issue 1, Page 9-15, Original Article

c Sharif University of Technology

AbstractTorsion has been recognized as a main failure modein past earthquakes. One e�cient method of reducingearthquake e�ects is the application of energy dissipa-tion devices, such as dampers. Friction dampers areamong the simplest energy dissipat ion devices. Al-though there is much research on the use of frictiondampers in symmetric buildings, there are fewer studiesreported on asymmetric buildings. Results of those lim-ited past studies show that the performance of frictiondampers in the control of torsion in asymmetric struc-tures is considerable. The aim of this investigation is to

determine e�ective parameters and their range of e�ec-tive values for torsional control of asymmetric buildingsby friction dampers. For this purpose, steel buildingshave been modeled and analyzed by OpenSees. Theasymmetric buildings in this study are assumed to beclassi�ed as mass eccentric buildings. These models aresymmetric, with respect to sti�ness and strength dis-tribution, and their eccentricity is due to their asym-metric mass distribution. Di�erent levels of mass ec-centricity are considered in parametric studies. Damperplacements are investigated to identify their optimumdistribution in having the largest e�ect in reducing theadverse e�ect of torsion in asymmetric buildings. Thecharacteristics of friction dampers are also changed tocover a wide range of realistic values. Also, consid-ered in parametric studies, are the properties of braces,which are connected to the friction dampers. The ef-fects of these parameters have been evaluated, not onlyin optimum placement, but, also, in the value of the slipload of friction dampers. The results show that the useof resulted optimum distribution and the recommendedcharacteristics of friction dampers can control torsion inasymmetric buildings.

Key Words: torsion, energy dissipation, friction damper,mass eccentric.

? corresponding authorReceived 5 Agust 2009 ; received in revised form 9 August 2010;accepted 17 January 2011