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Masonry Structures

SIDDHARTH SHANKARDepartment of Civil(structure)

Enineerin!ulc"o#$ Campus

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A%vantae of Masonry Structure Strength: Stron in compression Heat Absorber:Resists temp& fluctuation

Maintenance free' Most of #all not reuire paintin &

Fire resistant' ire protection %ue to formation of non*com+usti+le material&

Environmental-friendly: ,ea%in contri+utor to reen

+uil%in t"at "as lo# impact on nature

Great sound proofing: Bloc$s out noise more efficiently

t"an more tra%itional +uil%in material suc" as tim+er

Economic:-se of locally availa+le materials an%

availa+ility of la+or&

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Disa%vantae Moisture absorber' A+sor+s moisture #"en rainin& olor deterioration:E.treme #eat"er causes

masonry to %era%e/ materials suc" as #all surface

%ecolori0e %ue to frost %amae& Strength:Masonry structure "as lo# tensile strent"&

!pening:!ro+lem in lare openin&

Education:,ac$ of e%ucation in masonry& "eeds heavy foundation:Due to "eavy #ei"t/

lare foun%ation is reuire%& Also crac$in an%

settlement may occur&

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1asic Terms in Masonry ourse: Hori0ontal layer of +ric$s or stones& Bed:,o#er surface of +ric$s2stones in eac" course #"ic" is

perpen%icular to t"e line of pressure&

Bac#ing: $ne.pose% #all Facing:E.pose% to #eat"er

Hearting:1et#een t"e facin an% +ac$in

%oint: 1e% an% perpen%&

Header: ,ent" is perpen%icular to t"e face of t"e #all Stretcher:,onest si%e parallel to t"e face of t"e #all&

Bond:In%ivi%ual +ric$ units are tie% toet"er #it" mortar is

calle% as +on%&

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1asic Terms in Masonry loser: !ortion of +ric$ cut in suc" a manner t"at its one lonface remains uncut&

&ueen closer:,ent"*#ise cuttin of +ric$&

'ing closer: Cuttin off t"e trianular piece +et#een t"ecenter of one en% an% t"e center of t"e ot"er (lon) si%e&

Bat: 1ric$ cut across t"e #i%t"

Soldier' ,ai% vertically #it" t"e lon narro# si%e of t"e +ric$

e.pose%& Sailor: ,ai% vertically #it" t"e +roa% face of t"e +ric$

e.pose%&

(o)loc#',ai% on t"e lon narro# si%e #it" t"e s"ort en% of

t"e +ric$ e.pose%&

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1asic Terms in Masonry

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Construction Tec"noloy

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Construction Tec"noloy ,ap s"oul% +e minimum 324t"+ric$ alon t"e lent" of#all an% 325n%+ric$ across t"e t"ic$ness of #all&

1ric$s +ats s"oul% +e %iscourae%/ e.cept in special

locations& T"e vertical 6oint in t"e alternate courses s"oul% +e alon

t"e same perpen%&

All t"e finis"e% masonry #alls s"oul% +e cure% for at least

7 %ays& T"ic$ness of mortar 6oint s"oul% +e uniform an% not more

t"an 38mm in any case&

Hei"t of +ric$ masonry in one %ay s"oul% not e.cee%

3&9m

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Types of 1on% Stretc"er +on%

Hea%er +on%

Enlis" +on%

lemis" +on%

acin +on%

1ric$ on e%e +on%

Ra$in +on%

Dutc" +on%

:i0a +on%

;ar%en #all +on% Rat*trap +on%

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Types of 1on%

i' lemis" 1on% i' Enlis" 1on%

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S&N& English bond S&N& Flemish bond3 Hea%ers an% stretc"ers are lai% in

alternate courses&

3 Hea%ers an% stretc"ers are lai%

alternately in eac" course&

5 Stronest of t"e types of +on%s& 5 Comparatively less stron for #allsmore t"an 8 S$ille% la+or is not reuire% for itsconstruction

> S$ille% la+or reuire% for itsconstruction&

? ,ess mortar is use%& ? More mortar is use% %ue to use of

+ats&

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Rat*trap +on% S"iner an% ro#loc$ are visi+le on t"e face ofmasonry@ t"is ives t"e #all #it" an internal cavity

+ri%e% +y t"e Ro#loc$&

Economic use of +ric$&

T"e cavity provi%es t"ermal comfort insi%e t"e #all&

-se% in loa% +earin as #ell as t"ic$ partition #all&

T"e structural strent" increase% +y insertin steel&

Due to cavity/ t"e #ei"t of t"e +uil%in is re%uce%&

Aest"etically pleasin #all&

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Rat*trap +on%

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Hollo# concrete +loc$s

http://www.dimensionsinfo.com/wp-content/uploads/2010/02/Hollow-Block.jpg

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A%vantae of Hollo# concrete +loc$s

Hollo# +loc$ nee%s lo# maintenance& Hi" Dura+le&

Construction spee% is "i" #"en compare to conventional construction

systems&

It "as "i" tensile strent"&

Economical frien%ly an% c"eap rates&

It re%uces t"e +uil%in costs&

T"e acoustic system of t"e room is oo% #it" "ollo# cement construction&

Maintains t"e t"ermal +alance system of any "ollo# +loc$ construction&

It re%uces t"e la+or cost an% total construction cost& Hi" "eat an% #ater resistant&

Its no nee%s of plasterin

,o# #ater a+sorption t"an +ric$&

Main a%vantae/ +loc$ voi%s can +e fille% +y ot"er fillin materials&

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ompressed Earth Bloc#

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Advantage of ompressed Earth Bloc#

S"ippin cost' Suita+le soils are often availa+le at or near t"econstruction site&

-niformity' Manufacture% to a pre%icta+le si0e an% "as true flat

si%es an% ?

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Masonry as infill )alls

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Masonry as infill )alls Masonry in*fills cause un%esira+le effects un%er seismic loa%in'

s"ort*column effect/ soft*storey effect/ torsion/ an% out*of*plane

collapse&

In*fills are separate% from t"e RC frame an% %o not interfere #it"

t"e frame un%er lateral %eformations& All lateral force on t"e

+uil%in is carrie% +y t"e +are RC frame alone& In*fills are +uilt interal #it" t"e RC frame as non*structural

elements& T"e entire lateral force on t"e +uil%in is carrie% +y t"e

+are RC frame alone& Most common %esin practice in t"e

%evelopin countries& In*fills are +uilt interal #it" t"e RC frame/ an% consi%ere% as

structural elements& In*plane stiffness offere% +y t"e infill #alls is

consi%ere% in analysis& T"e forces from t"is analysis are use% in

t"e %esin of RC frame mem+ers an% 6oints&

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(einforced masonry

A construction system #"ere steelreinforcement is em+e%%e% in t"e mortar 6oints

of masonry or place% in "oles an% after fille%

#it" concrete or rout is calle% Reinforce%masonry& Reinforce% masonry can +e classifie%

into t"ree types'

Reinforce% "ollo# unit masonry Reinforce% route% cavity masonry

Reinforce% poc$et type #alls

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(einforced grouted cavity masonry

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(einforced poc#et cavity masonry construction

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*ypical anchorages of reinforcing bars

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$nreinforced masonry

,i$ely to +e %amae% %urin eart"ua$e&

Mortar "ol%in t"e masonry toet"er is enerally

not stron enou" to resist eart"ua$e forces&

Anc"orae of #alls to t"e floor an% t"e roof iscritical&

T"ese "ouses are #ea$ (+rittle) an% can +rea$

apart& Balls may fall a#ay or +uc$le/ resultin in

%amae&

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$nreinforced masonry

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onfined masonry

T"e masonry #alls carry t"e seismic loa%s an% t"e concrete isuse% to confine t"e #alls&

Construction system #"ere masonry structural #alls are

surroun%e% on all four si%es #it" reinforce% concrete&

Confinement s"oul% +e in vertical an% "ori0ontal +ot"%irection to resists lateral an% ravity loa%s&

T"e confinin mem+ers are effective for'

3& En"ancin t"e sta+ility an% interity of masonry #all for in*

plane an% out*of*plane eart"ua$e loa%s&5& En"ancin t"e strent" of masonry #all un%er E&

8& Re%ucin +rittleness of masonry improvin E performance&

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onfined masonry

T"e structural component of confine% masonry are' Masonry #all

Confinin elements (tie*+eams an% tie columns)

loor an% roof sla+ !lint" +an%

oun%ation

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onfined masonry

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C"apter*Desin of masonry

#alls for ravity

loa%sIS3?7

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+ntroduction to odal ,rovisions

Scope

Structural %esin of unreinforce% loa%

+earin an% non*loa% +earin #alls

constructe% #it" soli% or perforate%

+urnt clay +ric$/ concrete +loc$&

Do not apply to #alls constructe% inmu% mortars&

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alls Most essential component of +uil%in&

Enclose or %ivi%e space of +uil%in&

!rovi%e privacy/ affor% security an% protection

aainst "eat/ rain an% col%&

Desine% #all s"oul% "ave

A& Strent" an% sta+ility

1& Beat"er resistance an% t"ermal insulation

C& Dura+ility an% fire resistance

D& Soun% insulation

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alls ertical loa%*+earin mem+er/ t"e #i%t" of

#"ic" (lent") e.cee%s 4 times t"e t"ic$ness&

Isolate% vertical loa% +earin mem+er/ t"e

#i%t" of #"ic" %oes not e.cee% 4 times t"et"ic$ness is calle% column&

Types of #alls

,oa%*+earin #all* Desine% to carry super*

impose% loa% an% self #ei"t&

Non*loa% +earin #all* Desine% to carry self

#ei" only&

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alls

!artition #all' T"in internal #all use% to %ivi%e t"e space #it"in+uil%in&

Internal #all' ,oa% +earin partition #all&

!anel #all' E.ternal non*loa% +earin #all (commonly relate% to

frame structure) !arty #all' Ball separatin t"e a%6oinin +uil%ins& May or may

not +e loa% +earin&

Separatin #all' Ball separation %ifferent occupancies #it"in t"e

same +uil%in&

Curtain #all' Self*supportin #all carryin no ot"er vertical loa%

+ut su+6ect to lateral loa%s& E'ileco%eco%es3?

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.oad bearing alls

Soli% masonry #alls' Most commonly use% +ut may "ave openin& Cavity #alls' Ball comprisin t#o leaves/ eac" leave +ein +uil%

of masonry units an% separate% +y a cavity an% tie% toet"er #it"

metal ties or +on%in units to ensure t"at t#o leaves act as one

structural units& Space +et#een t#o leaves +ein left continuous or

fille% #it" ot"er non*loa% +earin insulatin material&

Solid all

avity

all

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.oad bearing alls

ace% #alls' Ball in #"ic" t"e facin an% +ac$in are of t#o%ifferent materials are +on%e% toet"er to ensure common action&

(IS3?

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/esign onsideration

;eneral Masonry structure ain sta+ility from t"e

supports offere% +y cross #alls/ floors/

roofs an% ot"er elements&

Structure is so planne% t"at eccentricity

of loa%in on t"e mem+ers is small as

possi+le&

Mi. proportions s"oul% follo# Ta+le 3(IS3?7) pae no& =

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/esign onsideration cont0

Selection of mortar Reuirement of mortar for masonry structure #or$a+ility/

strent"/ #ater retentively an% lo# %ryin s"rin$ae&

Mortar strent" in eneral s"oul% not +e reater t"an t"at of

masonry unit& Masonry unit strent"(N2mm5)

Mortar type

1elo# 9 M5

9 to 34&? M3

39*54&? H5

59 or a+ove H3

,etter H/ M an%

, in%icates t"e

"i" strent"/

me%ium

strent" an%

lo# strent"

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/esign onsideration cont01Sta+ility reuirement

,ateral support' Ball can +e laterally supporte% eit"er at vertical intervals +y

floor roof transmittin "ori0ontal forces to cross*#alls an% t"en to t"e

foun%ation or at "ori0ontal interval +y cross*#all/ piers transmittin

"ori0ontal forces to foun%ations& ,ateral support "as to perform t#o

important functions as' To resist "ori0ontal components of t"e forces so as to ensure t"e structure

aainst over*turnin&

To limit t"e slen%erness ratio of masonry elements in or%er to prevent

failure +y +uc$lin&

A%euate lateral support' If supports is capa+le of resistin t"e sum offollo#in lateral forces t"an #all consi%ere% as a%euate lateral support&

Simple static reactions at t"e point of lateral support to all t"e lateral loa%s&

5&9F of t"e total vertical loa% t"at t"e #all or column is %esine% to carry

at t"e point of lateral support&

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/esign onsideration cont01

Effective Height of )all T"e effective "ei"t of a loa% +earin #all is assesse% +ase% on t"e relative

stiffness of t"e elements of t"e structure connecte% to t"e #all toet"er #it"

t"e efficiency of t"e connection&

A #all is stiffene% +y floors / or roofs / suita+le cross #alls or any similar

construction element&

Refer' Effective

"ei"t of #all*

Ta+le 4

(IS3?7)pae no &33

E'ileco%ec

o%es3?

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/esign onsideration cont01Effective length of )all

Refer' Effective lent" of #all* Ta+le 9 (IS3?7) !ae no& 35Effective thic#ness of )all

Refer' Effective t"ic$ness of #all (Clause 4&9 of IS3?7) !ae no' 38

Slenderness ratio 2S(3

T"e ratio of effective "ei"t or effective lent" to t"e effective t"ic$ness of

#all #"ic"ever is less is t"e %esin value of slen%erness ratio&

T"e slen%erness ratio for a loa% +earin column s"all not e.cee% 35&

Ma.imum SR for a loa% +earin #all

No of Storey Ma.imum Slen%erness Ratio

-sin !ortlan% cement in mortar -sin mortar lime

Not e.cee%in 5 57 579 II) Bin% loa% on #alls an% slopin roof&

Seismic forces (In 0one I an% II/ not necessary an% 0one III/ I

an% I s"oul% a%opte%)

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Structural /esign cont0

,oa% %ispersion (Clause 9&8 IS3?

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Structural /esign cont01!ermissi+le stresses (Clause 9&4 IS3?)

Stress re%uction factor (Ks) %epen%s on SR an% eccentricity of

loa%in (Ta+le ?)

Area re%uction factor (Ka)/ Ka

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all !pening

Effect of openingsRe%uce lateral strent" of -RM

#alls an% s"oul% +e small L

centrally locate%&

Total lent" of openins s"oul%

+e "alffor one*storey an% one*

t"ir%for t#o* storey 1uil%ins&

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Refer'

N1C 3