behaviour of frames

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Behavior of Frames with Inl& Bracing under Lateral Load

Mohammed Ali Boodihal

II ME Structural Engineering

Under the Guidance of

Dr. B P Annapoorna

Associate rofessor

!e"artment of #ivil Engineering

U$#E

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Usual !esign

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Failures

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FAILU%E

SF'(S'%E) #LLASEME#*A+ISM

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Frames

•  %einforced #oncrete ,%#- frame.uildings are the most commont/"e of constructions in ur.anIndia0 which are su.1ected to

several t/"es of forces duringtheir lifetime0 such as staticforces due to dead and liveloads and dynamic forces due

to wind and earth2ua3es4

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 F%AMES

B%A#E! F%AME

I+FILL F%AME

BA%E F%AME

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Inll

• Infill are often used to fill the void between the vertical and horizontal

resisting elements of the building frames.

• Masonry infill are normally considered

as non-structural elements and theirstiffness contributions are generally

ignored in practice.

• But field evidence has shown that

continuous infill walls can help reduce

the vulnerability of RC Structures

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 '/"es of Inll

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Behaviour

•Infill alters the behavior of building from predominantlyframe action to predominantly truss action

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Behavior Infill walls have a very high initial lateral stiffness and low de-formab

hus introduction of infill in RC frames changes the lateral-load trans

mechanism of the structure from predominant frame action to predom

truss action which is responsible to reduce lateral deflections and bend

moments in the frame! there by decreasing the probability of collapse

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Behavior

• he infill capable of resisting the applied lateral seismic forces throug

a"ial compression along the diagonal so crac#s are formed which ser

as a energy dissipater.

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Failure Modes

 'he #orner #rushing ,##- mode

 'he !iagonal #om"ression ,!#- mode 'he Sliding Shear ,SS- mode

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!isadvantages

Short #olumn E5ect

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#a"tive(#olumn

 ')I#AL #A'I$E #LUM+FAILU%E

%ES'%I#'I+ ' '*E LA'E%AL !ISLA#EME+' F A #LUM+#%EA'I+G A #A'I$E(#LUM+ EFFE#'

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I+FILL F%AME

,a- Interaction .ehavior of frame and inll6 ,.- Analogous.raced frame

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 ')ES F B%A#I+G

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B%A#E! F%AME S)S'EMS

#%SS B%A#E! #*E$%+

B%A#E!

!IAG+AL B%A#E! 7(

B%A#E!

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Behavior of Braced Frame

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Behavior of Braced Frame

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Behavior of Braced Frame

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E8"erimental Investigation,9-

 'a.le 9: !escri"tion of $arious Frames,9-

!etails of the .areframe,9-

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Arrangement of Bracing,9-

,a- ,.-

,c-

,a-#orner Bracing %;,.-#entral Bracing %<,c-!iagonal Bracing %=

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Arrangement of Bracing,9-

Bare %# frame#orner to" .racing %#frame4

#entral to" .racing %# frame#orner to" .racing frame lled with concrete4!iagonal .racing %# frame4

#entral to" .racing frame lled with concrete4

!iagonal .racing frame lled with concrete4

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%esults,9-

#om"arison of ultimate loads fordi5erent frames

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%esults,9-

Braced and #oncrete InlledFrame

BracedFrame

Bare %#Frame

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#onclusions,9-

•  If the inll is stronger than the frame0 the failure mode

corres"onds to swa/ mechanism with ma1or tension crac3salong the tension column4 For .raced and "artiall/ inlled frames0 "ossi.le "lastic hinge locations are at the column.eam 1unction and the .ottom of column4

•  Based on a com"arison with the .are %# frames0 .raced

frames have shown an increase of 9>?4<@0;;4@0 and <in lateral load ca"acit/4 It s"ecies that the contri.ution of.racings is u" to a signicant level for the lateral strength .raced frames4

•  All .raced and "artiall/ inlled .raced frames have

signicantl/ less deCection in com"arison to the .are fram•  'hough contri.ution to the strength of "artiall/ inlled fram

is ;@ in com"arison to .raced frames0 it sti5ens the fram

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Model Anal/sis,;-

Elevation of Un.racedStructure

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Modeling Anal/sis,;-

LA+

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%esults,;-

Lateral !is"lacement in D

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#onclusions,;-

• !is"lacement of a structure decreases after the a""licatof .racing s/stem

•  'he ma8imum reduction in the lateral dis"lacementoccurs after the a""lication of cross .racing s/stem

• Bracing s/stem reduces .ending moments and shear

forces in the columns4•  'he "erformance of cross .racing is .etter than other

s"ecied .racing s/stems4

• Steel .racings can .e used to retrot e8isting structureand total weight will not change signicantl/ after

a""lication of .racing4

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Inference

• Inlled walls are normall/ considered non structural elements

are e5ective in carr/ing lateral load4

• All "artiall/ inlled and .raced frames have signicantl/ lessdeCection0 shear and .ending in com"arison to the .are fram*ence its advised to "rovide either at soft stor/ level4

• Ma8imum reduction in lateral dis"lacement is achieved ./

introduction of cross .racing4• racticall/0 the "artiall/ inlled and centre(.raced s/stem ma

.e via.le solution which ma/ not a5ect architectural or interifunction than that of corner and diagonal .racing "artiall/inlled s/tem for soft store/4 For shear wall cross(.raced with

inll will .e more e5ective4

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%eferences

9- Shailendra 7umar !amodar !u.e/ and Sunil ) 7ute0  Experimental

investigation on the ultimate strength of partially inlled and steel-bracreinforced concrete frames 0 International ournal of Advanced StructuEngineering ;9<0 :9

;- +auman Mohammed0 Islam +aHrul 0 Behaviour of Multistorey RCCStructure with i!erent "ype of Bracing System #$ Software $pproach%International ournal of Innovative %esearch in Science0 Engineering an

 'echnolog/0 $ol4 ;0 Issue 9;0 !ecem.er ;9<<- Santiago u1ol0 Amadeo Benavent(#liment0 Mario E %odrigueH0 and 4 a

Smith(ardo Masonry inll walls& an e!ective alternative for seismicStrengthening of low-rise reinforced concrete building Structures' 'he Jorld #onference on Earth2ua3e Engineering0 cto.er 9;(9?0 ;0Bei1ing0 #hina

=- Br/an Stanford Smith & Ale8 #oull0 "all Building Structures& $nalysis (esign0 A Jile/(Interscience u.lication0 9KK9