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IS 13920 : 2016
Indian Standard
Ductile Design and Detailing of Reinforced oncrete Structures Su!"ected to Seis#ic $orces ode of %ractice ( First Revision )
IS &7'020'99; 93'1&0
( )IS 2016
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Earthquake Engineering Sectional Committee, CED 39
FOREWORD This Indian Standard First Re!ision" #as ado$ted %& the 'ureau o( Indian Standards, a(ter the dra(t (inali)ed %& the Earthquake Engineering Sectional Committee had %een a$$ro!ed %& the Ci!il Engineering Di!ision Council* IS +3- . /90- 1Code o( 2ractice (or earthquakeresistant design and construction o( %uildings1 had $ro!isions (or addressing s$ecial (eatures in the design and construction o( earthquakeresistant RC %uildings* It included then, some details (or achie!ing ductilit& in rein(orced concrete RC" %uildings* To kee$ a%reast #ith the ra$id de!elo$ments de!elo$ments and e4tensi!e e4tensi!e research research on earthquak earthquakere eresista sistant nt design design o( RC structures structures,, the technical technical committee decided decided to (ormulate (ormulate se$arate $ro!isions $ro!isions (or earthquakere earthquakeresista sistant nt design design and detailing detailing o( RC structures, #hich resulted in the (ormulation o( IS /395 . /993 1Code o( 2ractice (or Ductile Design and Detailing o( Rein(orced Concrete Structures Su%6ected Su%6ected to Siesmic Forces1* IS /395 . /993 incor$orated some im$ortant $ro!isions that #ere not co!ered in IS +3- . /90- (or design o( RC structures* The (ormulation (ormulation o( the standard addressed the (ollo#ing salient as$ects. a"
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Signi(ica Signi(icant nt e4$erience e4$erience gained gained (rom $er(orma $er(ormance nce o( rein(orced rein(orced concrete concrete structur structures es that #ere #ere designed designed and detailed as $er IS +3- . /90- during $ast earthquakes* 7an& de(iciencies #ere identi(ied and corrected* 2ro!isions on design and detailing o( %eams and columns as gi!en in IS +3- . /90- #ere re!ised #ith an aim to $ro!ide them #ith adequate sti((ness, strength and ductilit& and to make them ca$a%le o( undergoing e4tensi!e inelastic de(ormations and dissi$ating seismic energ& in a sta%le manner* S$eci(ica S$eci(ications tions #ere #ere included included on lo#er limits limits (or strength strengthss o( material material o( earthquake earthquakeres resistan istantt RC structural s&stems* 8eometric constraints #ere #ere im$osed im$osed on crosssections o( (le4ural (le4ural mem%ers* mem%ers* 2ro!isions 2ro!isions #ere #ere re!ised re!ised on minimum and ma4imum rein(orcement limits* Requirements #ere made e4$licit (or detailing o( longitudinal rein(orcement in %eams at 6oint (aces, s$lices and anchorage requirements* 2ro!isions #ere included (or calculating seismic design shear (orce, and detailing trans!erse rein(orcement in %eams* For mem%ers mem%ers su%6ected su%6ected to a4ial a4ial load and %ending %ending moment, moment, constraints constraints #ere im$osed im$osed on crossse crosssectional ctional as$ect ratio and on a%solute dimensions* lso, $ro!isions are included (or /" location o( la$ s$lices, " calculation o( seismic design (or shear (orce o( structural #alls, and 3" s$ecial con(ining rein(orcement in regions o( columns o( columns that are e4$ected to undergo c&clic inelastic de(ormations during a se!ere earthquake shaking* S$eci(ica S$eci(ications tions #ere #ere included included on a seismi seismicc design design and detailing detailing o( rein(or rein(orced ced concrete concrete struct structural ural #alls* #alls* These $ro!isions assisted in /" estimation o( design shear (orce and %ending moment demand on structural #all sections, " estimation o( design moment ca$acit& o( #all sections, 3" detailing o( rein(orcement in the #all #e%, %oundar& elements, cou$ling %eams, around o$enings, at construction 6oints, and +" $ro!iding +" $ro!iding su((icient length (or de!elo$ment, la$ s$licing and anchorage o( longitudinal steel*
Follo#ing the earthquakes that occurred a(ter the release o( IS /395 . /993 es$eciall& the /990 :a%al$ur, :a%al$ur, 55/ 'hu6, 55+ Sumatra, 55- Sikkim, and 5// Sikkim earthquakes", it #as (elt that this Code needs (urther im$ro!ement* In this re!ision, the (ollo#ing changes are incor$orated. a"
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The title is re!ised re!ised to re(lect re(lect the 1Design1 1Design1 $ro!isio $ro!isions ns that e4isted e4isted and ne# ones ones added, added, that determine determine the si)ing, $ro$ortioning and rein(orcement in RC mem%ers meant to resist earthquake shaking* ll RC (rames, RC #alls and their elements in a structure need not %e designed to resist lateral loads and the designer ma& 6udiciousl& select e((ecti!e lateral load resisting RC (rames and #alls and design those mem%ers (or (ull design lateral (orce* ll columns in (rames not designed as lateral load resisting (rames #ill %e designed as gra!it& columns in line #ith the requirements o( 11* 7ost $ro!isions that e4isted earlier ha!e %een redra(ted* redra(ted* lso, lso, the sequence o( sections is reorgani)ed reorgani)ed (or greater clarit& to designers and (or remo!ing am%iguities* ll the (igures ha!e %een redra#n #hich increases the clarit&* Some ne# (igures ha!e %een added* The (ollo#ing ne# $ro!isions $ro!isions are added. /" Columnto%eam Columnto%eam strength ratio $ro!ision has %een added in kee$ing #ith the strong column %eam design de sign $hiloso$h& $hiloso$ h& (or moment re sisting (rames; (ra mes; #eak %eam " Shear Shear desi design gn o( o( %eam %eamc colu olumn mn 6oint 6oints; s; 3" Design Design o( slender slender RC structural structural #alls #alls is im$ro!ed* im$ro!ed* The $rinci$l $rinci$lee o( su$er$ositi su$er$osition on is dro$$ed dro$$ed (or
Continued on third cover "
IS 13920
:
Indian Standard D >D DETI=I>8 OF REI>FORCED CO>CRETE STR
RC moment resisting (rames,
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RC momen t re si st in g (rames unrein(orced masonr& in(ill #alls ,
#i th
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RC moment resisting (rames #ith RC structural #alls, and d" RC structural #alls. /*/*/ 2ro!isions o( this standard shall %e ado$ted in all lateral load resisting s&stems o( RC structures located in Seismic ?one III, I@ or @* The standard is o$tional in Seismic ?one II*
and the designer can 6udiciousl& identi(& the lateral load resisting s&stem %ased on relati!e sti((ness and location in the %uilding and design those mem%ers (or (ull lateral (orce* RC monolithic mem%ers assumed not to $artici$ate in the lateral (orce resisting s&stem see 3.7" shall %e $ermitted $ro!ided that their e((ect on the seis mic res$ onse o( the s&stem is accounted (or* Consequence o( (ailure o( structural and nonstructural mem%ers not $art o( the lateral (orce resisting s&stem shall also %e considered in design*
2 REFERENCES The (ollo#ing standards contain $ro!isions #hich, through re(erence in this te4t, constitute $ro!isions o( this standard* t the time o( $u%lication, the editions indicated #ere !alid* ll standards are su%6ect to re!ision, and $arties to agreements %ased on this standard are encouraged to in!estigate the $ossi%ilit& o( a$$l&ing the most recent editions o( the standards indicated %elo#. IS No.
Title
2lain and rein(orced concrete Code o( 2ractice fourth revision" /3+3 . 5/ Code o( 2ractice (or $restressed concrete second revision" /0- . 55 igh strength de(ormed steel %ars and #ires (or concrete rein(orcement fourth revision" /93 Criteria (or earthquake resistant design o( structures 2art /" . 55 8eneral $ro!isions and %uilding s fifth revision" 2art " . 5/+ =iquid retaining tanks Ele!ated and ground su$$orted 2art +" . 5/B Industrial structures including stack like structures first revision" +3- . 5/3 Earthquak e resistant design and construction o( %uildings Code o( 2ractice third revision" /-/0 . 5/+ Rein(orc ement cou$lers (or mechanical s$lices o( %ars in concrete +B- . 555
/*/* The $ro!isions (or RC structures gi!en herein a$$l& s$eci(icall& to monolithic RC construction, and not (or $recast RC structures* 2recast andAor $re stressed concrete mem%ers ma& %e used, onl& i( the& are designed to $ro!ide similar le!el o( ductilit& as that o( monolithic RC structures during or a(ter an earthquake* =ike#ise, (lat sla% structures must ha!e a lateral load resisting s&stem ca$a%le o( $ro!iding similar le!el o( $er(ormance as en!isioned in this standard and must %e designed (or dri(t com$ati%ilit& as $er 11* S$ecialist literature must %e re(erred to (or design and construction o( such structures* The adequac& o( such designs shall %e demonstrated %& adequate, a$$ro$riate e4$erimentation and nonlinear d&namic structural anal&ses* /*/*3 ll RC (rames, RC #alls and their elements in a structure need not %e designed to resist lateral loads /
3
3
IS 13920
:
S$eci(ication
3 TERMINOLOGY For the $ur$ose o( this standard, the (ollo#ing de(initions shall a$$l&*
loo$ ha!ing a /3B hook #ith an e4tension o( - times diameter %ut not -B mm" at each end, #hich is em%edded in the con(ined core o( the section, and $laced normal to the longitudinal a4is o( the RC %eam or column*
These are mem%ers generall& 3* / Beams hori)ontal" o( moment resisting (rames #ith 3*/5 (le4ural and shearing actions*
3
Sea# a%% a%so Ca%%e" S(&#a% a%%4 It is a !erticall& oriented $lanar element
3
3* Bo!"a#$ E%eme!&s 3 These are $ortions that is $rimaril& designed to resist lateral (orce e((ects along the ends o( a structural #all that are a4ial (orce, shear (orce and %ending moment" in its strengthened %& longitudinal and trans!erse o#n $lane* rein(orcement* The& ma& ha!e the same thickness It is a structural #all 3*//S5e()a% Sea# 2a%% as that o( the #all #e%* meeting s$ecial detailing requirements (or 3* 3 Co%m!s These are mem%ers generall& ductile %eha!iour s$eci(ied in 10* !ertical" o( moment resisting (rames #ith a4ial, SYMBOLS (le4ural and shearing actions*
3
3
It is that concrete #hich 3* + Co'e# Co!(#e&e is not con(ined %& trans!erse rein(orcement*
3
3* B T#a!s'e#se Re)!*o#(eme!& It is a continuous %ar ha!ing a /3B hook #ith an e4tension o( - times diameter %ut not -B mm" at one end and a hook not less than 95 #ith an e4tension o( times diameter %ut not -B mm" at the other end* The hooks shall engage $eri$heral longitudinal %ars* In general, the 95 hooks o( t#o successi!e crossties engaging the same longitudinal %ars shall %e alternated end (or end* Trans!erse rein(orcement also called hoo$s" in columns is t&$icall& called stirru$s and that in %eams is called crossties*
3
3* - G#a')&$ Co%m!s )! B)%")!+s It is a column, #hich is not $art o( the lateral load resisting s&stem and designed onl& (or (orce actions that is , a4ial (orce, shear (orce and %ending moments" due to gra!it& loads* 'ut, it should %e a%le to resist the gra!it& loads at lateral dis$lacement im$osed %& the earthquake (orces*
3
3* 0 La&e#a% Fo#(e Res)s&)!+ S$s&em It is that $art o( the structural s&stem #hich $artici$ates in resisting (orces induced %& earthquake*
3
3* Mome!&,Res)s&)!+ F#ame It is a three dimensional structural s&stem com$osed o( interconnected mem%ers, #ithout structural #alls, so as to (unction as a com$lete sel(contained unit #ith or #ithout the aid o( hori)ontal dia$hragms or (loor %racing s&stems- in #hich the mem%ers resist gra!it& and lateral (orces $rimaril& %& (le4ural actions*
3
3**/ Special Moment Resisting Frame (SMRF) It is a momentresisting (rame s$eciall& detailed to $ro!ide ductile %eha! iour as $er the requirements s$eci(ied in ., 6, 7 and /*
3
3** rdinar! Moment Resisting Frame (MRF) It is a momentresisting (rame not meeting s$ecial detailing requirements (or ductile %eha!iour* 3*9 L)!
3
It is a single steel %ar %ent into a closed
For the $ur$ose o( this standard, the (ollo#ing letter s&m%ols shall ha!e the meaning indicated against each; #here other s&m%ols are used, the& are e4$lained at the a$$ro$riate $lace* ll dimensions are in millimetre, loads in >e#ton and stresses in 72a, unless other#ise s$eci(ied* "e G E((ecti!e cross sectional area o( a 6oint "e6 G E((ecti!e shear area o( a 6oint "g G 8ross crosssectional area o( column, #all "h G ori)ontal rein(orcement area #ithin s$acing S "k G rea o( concrete core o( column "sd G Rein(orcement along each diagonal o( cou$ling %eam "sh G rea o( cross section o( %ar (orming s$iral or link "st G rea o( uni(orml& distri%uted !ertical rein(orcement " G @ertical rein(orcement at a 6oint # % G Width o( %eam $c , #c G Width o( column # 6 G E((ecti!e #idth o( a 6oint % G O!erall de$th o( %eam %k G Diameter o( column core measured to the outside o( s$iral or link d G E((ecti!e de$th o( mem%er d % G Diameter o( longitudinal %ar d # G E((ecti!e de$th o( #all section & s G Elastic modulus o( steel f ck G Characteristic com$ressi!e strength o( concrete cu%e f & G Hield stress o( steel rein(orcing %ars, or 5* $ercent $roo( strength o( rein(orcing steel h G =onger dimension o( rectangular con(ining link measured to its outer (ace
hc G De$th o( column
h 6 G E((ecti!e de$th o( a 6oint
com$ression (i%re
hst G Clear store& height
αG
Inclination o( diagonal rein(orcement in cou$ling %eam
ρG
rea o( longitudinal rein(orcement as a (raction o( gross area o( crosssection in a RC %eam, column or structural #all
h# G O!erall height o( RC structural #all '' G Clear s$an o( %eam 'd G De!elo$ment length o( %ar in tension l o G =ength o( mem%er o!er #hich s$eci al con(ining rein(orcement is to %e $ro!ided '# G ori)ontal length o( #allAlonger cross section dimension o( #all 's G Clear s$an o( cou$lings %eam M u G Design moment o( resistance o( entire RC %eam, column or #all section M ct G Design moment o( resistance o( to$ column at a 6oint M c% G Design moment o( resistance o( %ott om column at a 6oint M %l G Design moment o( resistance o( le(t %eam at a 6oint M %r G Design moment o( resistance o( right %eam at a 6oint M
h u
G ogging design moment o( resistance
o(
%eam at end
ρc
G rea o( longitudinal rein(orcement on the com$ression (ace o( a %eam as a (raction o( gross area o( crosssection
ρh"min G 7inimum area o( hori)ontal rein(orcement o( a structural #all as a (raction o( gross area o( crosssection ρ!,%e"min G 7inimum area o( !ertical rein(orcement in each %oundar& element o( a structural #all as a (raction o( gross area o( crosssection o( each %oundar& element ρ!,net"min G 7inimum area o( !ertical rein(orcement o( a structural #all as a (raction o( gross area o( crosssection o( the #all ρ!,#e%"min G 7inimum area o( !ertical rein(orcement in #e% o( a structural #all as a (raction o( gross area o( crosssection o( #e%
ρma4 G
s
M u G Sagging design moment o( resistance o(
%eam at end 'h u
M G ogging design moment o( resistance o( %eam at end '
ρmin G 7inimum area o( longitudinal rein(orcement to %e ensured on the tension (ace o( a %eam as a (raction o( gross area o( cross section
's
M u G Sagging design moment o( resistance o(
%eam at end ' '= u
M G Design moment o( resistance o( %eam
τc G
at a section o( RC %eam, column or structural #all
'R
(raming into column (rom the right M u# G Design moment o( resistance o( #e% o( RC structural #all alone
Design shear strength o( concrete
τc, ma4 G 7a4imum nominal shear stress $ermitted
(raming into column (rom the le(t M u G Design moment o( resistance o( %ea m
7a4imum area o( longitudinal rein(orce ment $ermitted on the tension (ace o( a %eam as a (raction o( gross area o( cross section
τv G
>ominal shear stress at a section o( RC %eam, column or structural #all
GENER8L SPECIFIC8TIONS
u G Factored a4ial load
.1 The design and construction o( rein(orced
s! G S$acing o( links along the longitud inal direction o( %eam or column
concrete %uildings shall %e go!erned %& $ro!isions o( IS +B-, e4ce$t as modi(ied %& the $ro!isions o( this standard (or those elements $artici$ating in lateral (orce resistance*
t G Thickness o( #e% o( RC structural #all D= *u,a
D= *u,%
G Factored shear (orce demand at end .2 o( M)!)mm +#a"e o* s(&#a% (o!(#e&e sa%% e %eam due to dead and li!e loads a" more /B m in height in Seismic ?ones M20- & M2 *o# than )%")!+sIII, I@ and @; and G Factored shear (orce demand at end ' o( %eam due to dead and li!e loads
%"
%ut not less than that required %& IS +B %ased on e4$osure conditions* * + G Design shear resistance o( a 6oint B*3 Steel rein(orcement resisting earthquakeinduced * u G Factored shear (orce (orces in RC (rame mem%ers and in %oundar& * us G Design shear resistance o((ered at a section elements o( RC structural #alls shall com$l& #ith %& steel links .3.1, .3.2 and .3.3* u ,-u G De$th o( neutral a4is (rom e4tr eme B*3*/ Steel rein(orcements used shall %e,
a"
o( grade Fe +/B or less con(orming to IS /0-"; and %" o( grade Fe B55 and Fe BB5, that is; high strength de(ormed steel %ars $roduced %& thermomechanical treatment $rocess ha!ing elongation more than /+*B $ercent, and con(orming to IS /0-* B*3* The actual 5* $ercent $roo( strength o( steel %ars %ased on tensile test must not e4ceed their characteristic 5* $ercent $roo( strength %& more than 5 $ercent*
.3.3 The ratio o( the actual ultimate strength to the
When an& such irregularities are ado$ted, detailed nonlinear anal&ses shall %e $er(ormed to demonstrate that there is no threat to loss o( li(e and $ro$ert&*
6 BE8MS 6.1 Ge!e#a% Requirements o( this section shall a$$l& to %eams resisting earthquakeinduced e((ects, in #hich the (actored a4ial com$ressi!e stress does not e4ceed 5*5 f ck * 'eams, in #hich the (actored a4ial com$ressi!e stress e4ceeds 5*5 f ck , shall %e designed as $er requirements o( 7*
actual 5* $ercent $roo( strength shall %e at least /*/B* -*/*/ 'eams shall $re(era%l& ha!e #idthtode$th ratio o( B*+ In RC (rame %uildings, lintel %eams shall $re(era%l& more than 5*3* not %e integrated into the columns to a!oid short column e((ect* When integrated, the& shall %e -*/* 'eams shall not ha!e #idth less than 55 mm* included in the anal&tical model (or structural -*/*3 'eams shall not ha!e de$th % more than /A+th o( anal&sis* Similarl&, $linth %eams #here $ro!ided", clear s$an* This ma& not a$$l& to the (loor %eam o( and staircase %eams and sla%s (raming into columns (rame staging o( ele!ated RC #ater tanks* shall %e included in the anal&tical model (or structural 6.1. )"& o*anal&sis* eam sa%% !o& e(ee" &e )"& o* s55o#&)!+ meme# (2 5%s ")s&a!(e o! e)&e# s)"e o* s55o#&) B*B RC regular momentresisting (rame %uildings shall ha!e $lanar (rames oriented along the t#o $rinci$al $lan dire ctions o( %uildi ngs* Irre gul ari tie s lis ted in IS /93 2art /" shall %e a!oided* 'uildings #ith )"& o* s55o#&)!+ meme#- (2 an& o( the listed irregularities $er(orm $oorl& during 0.7 &)mes earthquake shaking; in addition, %uildings #ith #ea"& o* s55o#&)!+ meme#- (1 see F)+. 18 a!" F)+. 1B4 (loating columns and set%ack columns also $er(orm $oorl&*
1, %lan ie of a )ea# olu#n :oint S>oing +ffecti?e )readt> and idt> of
:oint
1) /a@i#u# +ffecti?e idt> of ide )ea# and Required Trans?erse
FI8* / 'E7 CO=<7> :<>CTIO>S
Reinforce#ent
Trans!erse rein(orcement (or the #idth o( a %eam that e4ceeds #idth o( the column c shall %e $ro!ided as sho#n in Fig* /' throughout the %eam s$an including #ithin the %eam column 6oint
6.2 Lo!+)&")!a% Re)!*o#(eme!& -**/ The longitudinal rein(orcement in %eams shall %e as gi!en %elo#. a"
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'eams shall ha!e at least t#o / mm diameter %ars each at the to$ and %ottom (aces* 7inimum longitudinal steel ratio ρmin required on an& (ace at an& section is.
ρ min = 5*+
-**- Splicing of 'ongitudinal $ars -**-*/ 'ap splices When ado$ted, closed links shall %e $ro!ided o!er the entire length o!er #hich the longitudinal %ars are s$liced* Further, a" %"
the s$acing o( these links shall not e4ceed /B5 mm see Fig* 3"* the la$ length shall not %e less than the de!elo$ment length o( the largest longitudinal rein(orcement %ar in tension*
c"
la$ s$lices shall not %e $ro!ided, /" #ithin a 6oint ; " #ithin a distance o( d (rom (ace o( the
f ck f &
-** 7a4imum longitudinal steel ratio an& (ace at an& section is 5*5B*
column; and
ρma4 $ro!ided
3" #ithin a quarter length o( the %eam ad6oining the location #here (le4ural &ielding ma& occur under earthquake e((ects*
on
-**3 =ongitudinal steel on %ottom (ace o( a %eam (raming into a column at the (ace o( the column" shall %e at least hal( the steel on its to$ (ace at the same section* t e4terior 6oints, the anchorage length calculation shall consider this %ottom steel to %e tension steel*
d"
not more than B5 $ercent o( area o( steel %ars on either to$ or %ottom (ace shall %e s$liced at an& one section*
-**+ =ongitudinal steel in %eams at an& section on to$ or %ottom (ace shall %e at least /A+th o( longitudinal steel $ro!ided at the to$ (ace o( the %eam at the (ace o( the column; #hen the to$ longitudinal steel in the %eam at the t#o su$$orting column (aces is di((erent, the larger o( the t#o shall %e considered* -**B t an e4terior 6oint, to$ and %ottom %ars o( %eams shall %e $ro!ided #ith anchorage length %e&ond the inner (ace o( the column, equal to de!elo$ment length o( the %ar in tension $lus /5 times %ar diameter minus the allo#ance (or 95 %ends see Fig* "*
FI8 * 3 =2 =E>8T T =OCTIO> OF S2=ICI>8 =O>8IT= 'RS I> 'E7 -**-* Mechanical couplers
OF
7echanical cou$lers con(orming to IS /-/0" shall %e used #hen lon gitudinal steel %ars ha!e to %e c on ti nu ed (o r % eam s $a ns l arg er t ha n t he ir manu(actured lengths* Further, a"
onl& those mechanical s$lices con(orming to the a%o!e code and ca$a%le o( de!elo$ing the s$eci(ied tensile strength o( s$liced %ar shall %e $ermitted #ithin a distance equal to t#o times the de$th o( the mem%er (rom the mem%er (ace or in an& location #here &ielding o( rein(orcement is likel& to take $lace; and
%"
the s$acing %et#een ad6acent longitudinal %ars shall %e %ased also on the outer si)e o( the cou$ler to allo# eas& (lo# o( concrete*
-**-*3 elded splices FI8* >COR8E OF =O>8IT= 'E7 'RS T EJTERIOR 'E7 CO=<7> :OI>T
Welded s$lices shall not %e used in %eams (or a distance equal to t#o times the de$th o( the mem%er (rom the mem%er (ace or in an& location #here
&ielding o( rein(orcement is likel& to take $lace* t an& location,
not more than B5 $ercent o( area o( steel %ars shall %e s$liced at an& one section* Welding o( links, ties, inserts or other similar elements to !ertical rein(orcement %ars required as $er design is not $ermitted, in an& seismic )one*
*u,a / *u,a
s 'h 3 /*+ Mu + M u and
''
*u,% / *u,%D= 0 /*+
u s
"
6.3 T#a!s'e#se Re)!*o#(eme!&
For s#a& to le(t.
M
*
u + M
'h
''
*u,a / *u,aD= 1 /*+
-*3*/Onl& !ertical links shall %e used in %eams see Fig* +"; inclined links shall not %e used* nd, a"
D=
h
* u,% / *u,%D= 0 /*+ M u
and
+ M u's
''
in normal $ractice, a link is made o( a single %ent %ar* 'ut, it ma& %e made o( t#o %ars also,
Mu
h
+ M u
's
'' s
namel& a <link #ith a /3B hook #ith an
u
e4tension o( - times diameter %ut not less than -B mm" at each end, em%edded in the core concrete, and a crosstie see Fig* +'"* %" the hooks o( the links and crossties shall engage around $eri$heral longitudinal %ars* Consecuti!e crossties engaging the same longitudinal %ars shall ha!e their 95 hooks at o$$osite sides o( the %eam* When the longitudinal rein(orcement %ars are secured %& crossties in %eams that ha!e a sla% on one side, the 95 hooks o( the crossties shall %e $laced on that side*
h
#here M u , M , M u
's
'h
and M u
hogging moments o( resistance o( the %eam section at ends " and $, res$ecti!el&* These shall %e calculated D= as $er IS +B-* '' is clear s$an o( the %eam* *u,a and D= *u,% are the (actored shear (orces at ends " and $, res$ecti!el&, due to !ertical loads acting on the s$an; the $artial sa(et& (actor (or dead and li!e loads shall %e /*, and the %eam shall %e considered to %e sim$l& su$$orted (or this estimation* The design shear (orce demand at end " o( the %eam shall %e the larger o( the t#o !alues o( * u,a com$uted a%o!e* Similarl&, the design shear (orce demand at end $ shall %e the larger o( the t#o !alues o( * u,% com$uted a%o!e* a" (actored shear (orce as $er linear structural anal&sis; and %" (actored gra!it& shear (orce, $lus equili%rium shear (orce #hen $lastic hinges are (ormed at %oth ends o( the %eam see Fig* B" gi!en %& . /" For s#a& to right.
FI8* + DETI=S OF TR>S@ERSE R EI>FORCE7E>T 'E7S -*3* The minimum diameter o( a link shall %e mm* -*3*3Shear (orce ca$acit& o( a %eam shall %e more than larger o(,
I>
are sagging and
FI8* B C=C<=TIO> OF DESI8> SER FORCE DE7>D O> 'E7S <>DER 2=STIC I>8E CTIO> T TEIR E >DS -*3*+ In the calculation o( design shear (orce ca$acit& o( RC %eams, contri%utions o( the (ollo#ing shall not %e considered. a"
'ent u$ %ars,
FI8 * - DETI=S %"
Inclined links, and
c"
Concrete in the RC section*
OF
TR>S@ERSE R EI>FORCE7E>T I> 'E7S
-*3*B Close Spacing of 'in2s S$acing o( links o!er a length o( d at either end o( a %eam shall not e4ceed, a"
d A+;
%"
ti mes the di am et er o( the sm al le st longitudinal %ar; and /55 mm see Fig* -"*
c"
-*3*B*/The (irst link shall %e at a distance not e4ceeding B5 mm (rom the 6oint (ace* -*3*B* Closel& s$aced links shall %e $ro!ided o!er a
and inclined mem%ers resisting earthquakeinduced e((ects, in #hich the (actored a4ial com$ressi!e stress due to gra!it& and earthquake e((ects e4ceeds 5*5 f ck * The (actored a4ial com$ressi!e stress considering all load com%inations relating to seismic loads shall %e limited to 5*+5 f ck in all such mem%ers, e4ce$t in those co!ered in 10* For !arious sha$es o( columns other than rectangular an d ci rc ula r l ike 1 T1 s ha$ ed , 1J1 sha$ed, etc*, a$$ro$riate designs and detailing shall %e carried out using s$ecialist literature #here such columns are $art o( lateral load resisting s&stems*
7.1.1 The minimum dimension o( a column shall not %e less than,
length equal to d on either side o( a section #here (le4ural &ielding ma& occur under earthquake e((ects*
a"
7 COL
7.1.2 The crosssection as$ect ratio that is, ratio o(
Requirements o( this section shall a$$l& to
FI8 * 0 7I>I7<7 SI?E
is diameter o( the largest
diameter longitudinal rein(orcement %ar in the %eam $assing through or anchoring into the column at the 6oint, or %" 355 mm see Fig* 0"*
O!er the remaining length o( the %eam, !ertical links shall %e $ro!ided at a s$acing not e4ceeding d A*
7.1 Geome$
5 d %, #here d %
OF
columns
RC C O=<7>S 'SED
O>
smaller dimension to larger dimension o( the cross section o( a column or inclined mem%er" shall not %e
DI7ETER
OF
=R8EST =O>8IT= R EI>FORCE7E>T 'R
I>
'E7S FR7I>8
I>TO IT
less than 5*+B* @ertical mem%ers o( RC %uildings %eams corres$onding to )ero a4ial (orce on the design #hose crosssection as$ect ratio is less than 5*+ 1M interaction diagram* shall %e designed as $er requirements o( 9* 0**/* This check shall %e $er(ormed at each 6oint (or %oth 7.2 Re%a&)'e Se!+&s o* Beams a!" Co%m!s a& $ositi!e and negati!e directions o( shaking in the a >o)!& $lane under consideration* Further, in this check, design moments o( resistance in %eams" meeting at a 0**/ t each %eamcolumn 6oint o( a momentresisting 6oint shall %e considered in the same direction, and (rame, the sum o( nominal design strength o( similarl& the design moments o( resistance o( columns meeting at that 6oint #ith nominal strength columns" at the same 6oint shall %e considered to %e calculated (or the (actored a4ial load in the direction in the direction o$$osite to that o( the moments in o( the lateral (orce under consideration so as to gi!e the %eams* least column nominal design strength" along each $rinci$al $lane shall %e at least /*+ times the sum0**/*3 o( This check shall %e #ai!ed at all 6oints at roo( le!el nominal design strength o( %eams meeting at that onl&, in %uildings more than + store&s tall* 6oint in the same $lane see Fig* "* The $ro!isions o( 7.2 are not a$$lica%le (or (lat sla% In the e!ent o( a %eamcolumn 6oint not con(orming structures* to a%o!e, the columns at the 6oint shall %e considered 7.3 Lo!+)&")!a% Re)!*o#(eme!& to %e gra!it& columns onl& and shall not %e considered as $art o( the lateral load resisting s&stem* 0*3*/ Circular columns shall ha!e minimum o( - %ars* 0**/*/ The design moments o( resistance o( a %eam shall %e estimated %ased on the $rinci$les o( mechanics and the limiting strain states o( the limit state design method enunciated in IS +B-* The design moment o( resistance o( a column shall %e estimated as in case o(
0*3* Splicing of 'ongitudinal $ars 0*3**/ 'ap splices When ado$ted, closed links shall %e $ro!ided o!er the entire length o!er #hich the longitudinal %ars are s$liced* Further,
FI8* STRO>8 CO=<7> 3 WEK 'E7 R ELT
FI8 * 9 R EI>FORCE7E>T R ELT a" %"
c"
I>
CO=<7>S WIT 2RO:ECTIO> 7ORE T> /55 77 'EHO>D CORE
the s$acing o( these links shall not e4ceed /55 mm* the la$ leng th shall not %e less than the de!elo$ment length o( the largest longitudinal rein(orcement %ar in tension* la$ s$lices shall %e $ro!ided onl& in the central hal( o( clear column height, and not
columns, it shall ha!e at least the minimum longitudinal and trans!erse rein(orcement gi!en in this standard* %"
/" #ithin a 6oint, or
When the contri%ution o( this area is not considered in the estimate o( strength o( columns, it shall ha!e at least the minimum longitudinal and trans!erse rein(orcement gi!en in IS +B-*
" #ithin a distance o( d (rom (ace o( the 7. T#a!s'e#se Re)!*o#(eme!& %eam* 0*+*/ Trans!erse rein(orcement shall consist o( closed loo$, d" not more than B5 $ercent o( area o( steel %ars shall %e s$liced at an& one section* a" s$iral or circular links in circular columns, and e"
la$ s$lices shall not %e used (or %ars o( diameter larger than 3 mm (or #hich mechanical s$licing shall %e ado$ted*
0*3** Mechanical couplers 7echanical cou$lers con(orming to IS /-/0" shall %e use d* Furt her, onl & tho se mechanical s$ li ces con(orming to the a%o!e standard and ca$a%le o( de!elo$ing the s$eci(ied tensile strength o( s$liced %ar shall %e $ermitted #ithin a distance equal to t#o times the de$th o( the mem%er (rom the column (ace in an& location #here &ielding o( rein(orcement is likel& to take $lace* 0*3**3 elded splices Welded s$lices shall not %e used in columns (or a distance equal to t#o times the de$th o( the mem%er (rom the mem%er (ace or in an& location #here &ielding o( rein(orcement is likel& to take $lace* t an& location, not more than B5 $ercent o( area o( steel %ars shall %e s$liced at an& one section* 'ut, #elding o( links, ties, inserts or other similar elements to !ertical rein(orcement %ars required as $er design is not $ermitted, in an& seismic )one* 0*3*3 column that e4tends more than /55 mm %e&ond the con(ined core o#ing to architectural requirement see Fig* 9" shall %e detailed in the (ollo#ing manner. a " Wh en t he c on tr i% ut io n o ( t hi s a re a i s considered in the estimate o( strength o(
%"
rectangular links in rectangular columns*
In either case, the closed link shall ha!e /3B hook ends #ith an e4tension o( - times its diameter %ut not -B mm" at each end, #hich are em%edded in the con(ined core o( the column see Fig* /5"* 0*+* When rectangular links are used, a"
the minimum diameter $ermitted o( trans!erse rein(orcement %ars is mm, #hen diameter o( longitudinal %ar is less than or equal to 3 m m, an d / 5 mm, #h en diameter o( longitudinal %ar is more than 3 mm; %" the ma4imum s$acing o( $arallel legs o( links shall %e 355 mm centre to centre; c" a crosstie shall %e $ro!ided, i( the length o( an& side o( the link e4ceeds 355 mm see Fig* /5'"; the crosstie shall %e $laced $er$e ndicu lar to thi s link #hose length e4ceeds 355 mm* lternati!el&, a $air o( o!erla$$ing links ma& %e $ro!ided #ithin the column see Fig* /5C"* In either case, the hook ends o( the links and crossties shall engage around $eri$heral longitudinal %a rs * Consecuti!e crossties engaging the same longitudinal %ars shall ha!e their 95 hooks on o$$osite sides o( the column* Crossties o( the same or smaller %ar si)e as the hoo$s shall %e $ermitted; and,
FI8* /5 DETI= d"
OF
TR>S@ERSE R EI>FORCE7E>T
the ma4imum s$acing o( links shall %e hal( the least lateral dimension o( the column, e4ce$t #here s$ecial con(ining rein(orcement is $ro!ided as $er /*
I>
CO=<7>S
/" For s#a& to right.
( M) * = /*+ u
7. =es)+! Sea# Fo#(e )! Co%m!s
( M s
= /*+
h
's
#here M , M , M u
structural anal&sis; and
u
hst
h u
* u
(actored shear (orce demand as $er linear
u
,
" For s#a& to le(t.
The design shear (orce demand on columns is the larger o(,
a"
+ M 'h
s
u
u
+ M u
)
hst
,
'h
and M u are design sagging and
%"
(actored equili%rium shear (orce demand #hen $lastic hinges are (ormed at %oth ends o( the %eams gi!en %&.
hogging moments o( resistance o( %eams (raming into the column on o$$osite (aces " and $, res$ecti!el& , #ith one hogging moment and the other sagging see Fig* //"; and hst the store& height* The design moments o( resistance o( %eam sections shall %e calculated as $er IS +B-*
7..1 The calculation o( design shear (orce ca$acit&
" /A- o( clear s$an o( the mem%er; or 3" +B5 mm*
o( RC columns shall %e calculated as $er IS +B-*
/ SPECI8L CONFINING REINFORCEMENT
%"
ha!e a s$acing not more than, /" "
/A+ o( minimum mem%er dimension o( the %eam or column; - times diameter o( the smallest longitudinal rein(orcement %ars; and
3" /55 mm link* Te #e;)#eme!&s o* &)s se(&)o! sa%% e me& )& )! ea ms a!" (o% m!s- !% ess a %a# +e# amo !& o* a!s'e#se #e)!*o#(eme!& )s %ar #e;)#e" *#om sea# c" ha!e area "sh o( cross section o( the /.1 Fle4ural &ielding is likel& in %eams during (orming links or s$iral o( at least. /" in circular links or s$irals.
strong earthquake shaking and in columns #hen the shaking intensit& e4ceeds the e4$ected intensit& o( earthquake shaking see Fig* /"* This s$ecial con(inin g rein(orcement shall, a"
"sh = Maimum of
%e $ro!ided o!er a length l o (rom the (ace o(
/*9 s % f ck "g −/ ! k f "k & f 5*5+ s ck
%
the 6oint to#ards mids$an o( %eams and mid heights o( columns, on either side o( the 6oint; #here l o is not less than /"
larger lateral dimension o( the mem%er at the section #here &ielding occurs,
#here
!
k
f &
sv G $itch o( s$iral or s$acing o( links, %k G diameter o( core o( circular column measured to outside o( s$iralAlink,
FI8* // EL SER FORCE DE7>D O> CO=<7> 'E7 E >DS
WE>
2=STIC I>8ES
RE
FOR7ED
T
FI8* / CO=<7>
>D :OI>T
f ck G characteristic com$ressi!e strength o( concrete cu%e, f &
G 5* $ercent $roo( strength o( trans!erse steel rein(orcement %ars,
DETI=I>8
/.2 When a column terminates into a (ooting or mat, s$ecial con(ining rein(orcement shall e4tend at least 355 mm into the (ooting or mat see Fig* /3"*
"g G gross area o( column crosssection, and "k G area o( concrete core o( column G
"
"s h
%k +
in rectangular links.
= Maimum of
π
5*/ s s! 5*5B h
h f "g ck f &
−/ "k
f ck f &
#here h G l on ge r d im en si on o( r ec ta ng ul ar l in k measured to its outer (ace, #hich does not e4ceed 355 mm see Fig* /5'", and "k G area o( con(ined concrete core in rectangular link measured to its outer dimensions* h o( the link could %e reduced %& introducing crossties see Fig* /5C"* In such cases, "k shall %e measured as o!erall core area, regardless o( link
FI8* /3 2RO@ISIO> OF S2ECI= CO>FI>I>8 R EI>FORCE7E>T I> FOOTI>8
/. 3 When the calculated $oint o( contra(le4ure, under arrangement* ooks o( crossties $eri$heral longitudinal %ars*
shall
engage
the e((ect o( gra!it& and earthquake e((ects, is not #ithin the middle hal( o( the mem%er clear height, s$ecial con(ining rein(orcement shall %e $ro!ided o!er the (ull height o( the column* *+ S$ecial con(ining rein(orcement shall %e $ro!ided o!er the (ull height o( a column #hich has
signi(icant !ariation in sti((ness along its height* This !ariation in sti((ness ma& result due to a%ru$t changes in cross section si)e, or unintended restraint to the column $ro!ided %& stairsla%, me))anine (loor, $linth or lintel
FI8 * /+ CO=<7>S WIT @RI'=E STIFF>ESS #c
%eams (raming into the columns, RC #all or masonr& #all ad6oining column and e4tending onl& (or $artial column height*
min [# %
+ 5*B
]
<
# % *
hc if #c
; #here
*B Columns su$$orting reactions (rom discontinued sti(( mem%ers, such as #alls, shall %e $ro!ided #ith s$ecial con(ining rein(orcement o!er their (ull height* see Fig* /+"* This rein(orcement shall also %e $laced a%o!e the discontinuit& (or at least the de!elo$ment length o( the largest longitudinal %ar in the column* Where the column is su$$orted on a #all, this rein(orcement shall %e $ro!ided o!er the (ull height o( the column; it shall also %e $ro!ided %elo# the discontinuit& (or the same de!elo$ment length*
# % G #idth o( %eam and #cG #idth o( column hc G de$th o( column in considered direction*
9*/* %esign Shear Stress %emand on a +oint a " De si gn s he ar st re ss d em an d a ct in g hori)ontall& along each o( the t#o $rinci$al $lan directions o( the 6oint shall %e estimated (rom earthquake shaking considered along each o( these directions, using
9 BE8M,COLOINTS OF MOME NT,
τ 6dJ
RESISTING FR8MES
τ
9.1 =es)+! o* Beam,Co%m! >o)!& *o# =)s&o#&)o!a% Sea#
6dH
9.1.1 Shear Strength of Concrete in a +oint
B
τ 6c = /* /* 5
%"
"e6 f ck "
e6
f
ck
"e f ck 6
(or 6oints con(ined %& %eams on all (our (aces (or 6oints con(ined %& %eams on three (aces (or other 6oints
=
* d6J # 6 6 * d6H # 6 6
(or shaking along $lan direction J o( earthquake shaking,
(or shaking along $lan direction H o( earthquake shaking
It shall %e ensured that the 6oint shear ca$acit& o( 6oint concrete estimated using 9.1.1 e4ceeds %oth τ 6dJ and τ 6dH*
The nominal shear strength τ 6c o( concrete in a %eam column 6oint shall %e taken as
/*
=
Design shear (orce demands * 6dJ and * 6dH acting hori)ontall& on the 6oint in $rinci$al $lan directions J and H shall %e estimated considering that the longitudinal %eam %ars in tension reach a stress o( /*B f & #hen o!er strength $lastic moment hinges are (ormed at %eam ends"*
#here "e6 is e((ecti!e shear area o( 6oint gi!en %& # 6 6, 9.1.3 idth of $eam Column +oint in #hich # 6 is the e((ecti!e %readth o( 6oint direction &#o+ o( shear (orce and 6 e! eam $er$endicular to #e)!*o#(eme!&the e&e!"s eam, the m)!)mm e((ecti!e #idth o( o* 6oint the direction o( eam sa%% e 20 &)mes &e ")ame&e# o* &e %a#+es& %o!+)& (o%m! ?o)!&- &e )"& &ealong (o%m! 5a#a%%e% &o shear (orce* The e((ecti!e #idth o( 6oint # 6 see Fig* /B" shall %e o%tained (rom (ollo#ing.
FI8* /B 2=> @IEW OF 'E7 CO=<7> :OI>T SOWI>8 EFFECTI@E 'REDT >D WIDT OF :OI>T
9.2 T#a!s'e#se Re)!*o#(eme!& 9**/ Confining Reinforcement in +oints
9** In the e4terior and corner 6oints, all /3B hooks o( crossties should %e along the outer (ace o( columns*
10 SPECI8L SE8R 8LLS e! a%% *o# 'e#&)(a% *a(es o* &e ?o)!& a#e a')!+ eams *#am)!+ )!&o &em (o'e#)!+ a& %eas& 7 5e#(e!& o* &e )"& o! ea( *a(e10.1Ge!e#a% 8& %ea s& a% * &e s5e ()a % (o! @ !)! + #e)!*o#(eme!& #e;)#e" as 5e# / aℜ)#eme!&s &e &o e!"s o* (o% m!s- sa% % e 5#o' S5a()!+ o* &ese a!s'e#se %)!s sa%% !o& e(ee" 10 mm. /5*/*/ The requirements o( this section a$$l& to s$ecial e! a%% *o# 'e#&)(a% *a(es o* &e ?o)!& a#e !o& a')!+ eamsshear *#am)!+ *o#resisting 'e#&)(a% *a(es a'e #alls )!&o that &em are $arto#o(e! laterala%%(orce s5e()a% (o!@!)!+ #e)!*o#(eme!& #e;)#e" as 5e# / a& &e &o e!"s o* (o%m!s sa%% e 5#o')"e" &#o+ &e ?o)!& )&) s&stem o( earthquakeresistant RC %uildings* s5a()!+ o* &ese a!s'e#se %)!s sa%% !o& e(ee" 10 mm. /5*/* The minimum thickness o( s$ecial shear #alls shall not %e less than, a"
/B5 mm; and
%"
355 mm (or %uildings #ith cou$led shear #alls in an& seismic )one*
The minimum thickness $ro!ided must con(orm to the (ire resistance requirements %ased on occu$anc& as laid do#n in IS +B-* /5*/*3 The minimum ratio o( length o( #all to its thickness shall %e +* /5*/*+ S$ecial shear #alls shall %e classi(ied as squat, intermediate or slender de$ending on the o!erall height h# to length '# ratio as a"
Squat #alls. h# A '# /,
%" c"
Intermediate #alls. / ≤ h# A '# ≤ , and Slender #alls. h# A '# M *
Ta%e 1 M)!)mm Re)!*o#(eme!& )! RC Sea# a%%s
/5*/*B In the design o( (langed #all sections, onl& that $art o( the (lange shall %e considered #hich e4tends %e&ond the (ace o( the #e% o( the structural #all at least (or a distance equal to smaller o(,
Clause /5*/*- " S%. T$5e No o* a%% . i"
a"
actual #idth a!aila%le;
%"
hal( the distance to the ad6acent structural #all
Re)!*o#(eme!& =e&a)%s
p h 4min
Squat #all s B
5*55
( p ! ) min
( t l�
p!,net
/5*/*- S$ecial shear #alls shall %e $ro!ided #ith uni(orml& s$aced rein(orcement in its crosssection along !ertical and hori)ontal directions* t least minimum area o( rein(orcement %ars as indicated Ta%le / shall %e $ro!ided along !ertical and hori)ontal directions*
a in
p
ii)
#alls
)
p !,#e%
)
v $ro!ided
Intermediate ph )
)
%"
*B p !,#e% ) J
* 1 5*5
� ' )
L
$ro!ided
5*55 B
)
5*55 B
min
)
p
and
iii" Slender
)
min
pv,#e
)
p!,net
5*55
� '
5
mi n
5*55 B
)
5*55 B + 5*5/3 0B
( t l # * ' � #)
min
#all thickness is 55 mm or higher*
h
)
#
)min
pv,e#
72a; or
5*55 B + 5*5/3 0B( t # l * ' � #) ( h# l 5*55 B + 5*B p 5*55 B)
min
p h
#alls
(actored shear stress demand in the #all e4ceeds 5*B f ck
)
5*55 5
p !,#e%
/5*/*0 Rein(orcement %ars shall %e $ro!ided in t#o curtains #ithin the crosssection o( the #all, #ith each
a"
#
5*55 B )
mi
!,net
curtain ha!ing %ars running along !ertical hori)ontal directions, #hen,
)+
< ph )
min
p !,%e
(ph
5*55 B + 5*B /
t
/A/5th o( the total #all height*
l
h #
#e%; and c"
(
When steel is $ro!ided in t#o la&ers, all !ertical steel /5** Design shear strength τc o( concrete shall %e %ars shall %e contained #ithin the hori)ontal steel calculated as $er Ta%le /9 o( IS +B-* %ars; the hori)ontal %ars shall (orm a closed core /5**3 When nominal shear stress demand τv on a #all is, concrete area #ith closed loo$s and crossties* a" more than ma4imum design shear strength /5*/* The largest diameter o( longitudinal steel %ars used in an& $art o( a #all shall not e4ceed /A/5th o( τc,ma o( concrete gi!en in Ta%le 5 o( IS the 4 +B-", thickness o( that $art* the #all section shall %e redesigned; /5*/*9 The ma4imum s$acing o( !ertical or hori)ontal %" less than ma4imum design shear strength rein(orcement shall not e4ceed smaller o(, τc,ma4 o( concrete and more than design shear strength τc o( concrete, design a" /ABth hori)ontal length '# o( #all; hori)ontal shear rein(orcement shall %e %" 3 times thickness t # o( #e% o( #all; and $ro!ided o( area "h gi!en %&. c" +B5 mm* /5*/*/ 5 S$ ecial shear #alls shal l %e (ounded on $ro$er l& des ign ed (ou ndati ons and sha ll not %e discontinued to rest on %eams, columns or mem%ers*
inclined
* us
"h
=
5*0 f
&
d s Integral
=
* u
5*0 f
− τc t # d # &
d s Integral
,
#hich shall not %e less than the minimum area o( hori)ontal steel as $er 10.1. ; and
10.2 =es)+! *o# Sea# Fo#(e 10.2.1 >ominal shear stress demand shall %e estimated as.
τ =
* u t # d #
,
τ!
on a #all
c"
less than design shear strength τc o( concrete, hori)ontal shear rein(orcement shall %e the minimum area o( hori)ontal steel as $er 10.1. *
10.3=es)+! *o# 8)a% Fo#(e a!" Be!")!+
#here * u is (actored shear (orce, t # thickness o( the Mome!& #e%, and d # e((ecti!e de$th o( #all section along the Design moment o( resistance M u o( the #all section length o( the #all", #hich ma& %e taken as 5* '# /5*3*/ (or su%6ected to com%ined %ending moment and rectangular sections* com$ressi!e a4ial load shall %e estimated in accordance #ith requirements o( limit state design method gi!en
in IS +B-, using the $rinci$les o( mechanics in!ol!ing equili%rium equations, strain com$ati%ilit& conditions and constituti!e la#s* The moment o( resistance o( slender rectangular structural #all section #ith uni(orml& distri%uted !ertical rein(orcement ma& %e estimated using e4$ressions gi!en in nne4 * E4$ressions gi!en in nne4 are not a$$lica%le (or structural #alls #ith %oundar& elements* /5*3* The cracked (le4ural strength o( a #all section shall %e greater than its uncracked (le4ural strength*
and ha!e a s$acing not more than, a"
/A3 o( minimum mem%er dimension o( the %oundar& element; %" - times diameter o( the smallest longitudinal rein(orcement %ars; and c" /55 mm %ut ma& %e rela4ed to /B5 mm, i( ma4imum distance %et#een cross tiesA$arallel legs o( links or ties is limited to 55 mm,
& !ee" !o& e %ess &a! 100 mm.
/5*3*3 In structural #alls that do not ha!e %oundar& elements, at least a minimum o( + %ars o( / mm diameter arranged in la&ers, shall %e concentrated 10.. Bo!"a#$ e%eme!&s !ee" !o& e 5#o')"e"- )* &e as !ertical rein(orcement at the ends o( the #all o!er e!&)#e a%% se(&)o! 10.Co5%)!+ Beams)s 5#o')"e" )& s5e()a% (o!@!)!+ #e) a length not e4ceeding t#ice the thickness o( RC #all* /5*B*/ Co$lanar s$ecial structural #alls ma& %e connected %& means o( cou$ling %eams*
10.Bo!"a#$ E%eme!&s
/5*B* I( earthquake induced shear stress τve in cou$ling 'oundar& elements are $ortions along the #all edges %eam e4ceeds that are strengthened %& longitudinal and trans!erse ' f ck rein(orcement e!en i( the& ha!e the same thickness as %s , τ>!e5*/ that o( the #all #e%* It is ad!antageous to $ro!ide %ou nda r& elemen ts #ith dimen sion greate r th an #here 's is clear s$an o( cou$ling %eam and % o!erall thickness o( the #all #e%* de$th, the entire earthquakeinduced shear, %ending moment and a4ial com$ression shall %e resisted %& /5*+*/ 'oundar& elements shall %e $ro!ided along the diagonal rein(orcement alone* Further, !ertical %oundaries o( #alls, #hen the e4treme (i%re com$ressi!e stress in the #all e4ceeds 5* f ck due to (actored gra!it& loads $lus (actored earthquake (orce* 'oundar& elements ma& %e discontinued at ele!ations #here e4treme (i%er com$ressi!e stress %ecomes less than 5*/B f ck * E4treme (i%re com$ressi!e stress shall %e estimated using a linearl& elastic model and gross section $ro$erties* /5*+* %oundar& element shall ha!e adequate a4ial load carr&ing ca$acit&, assuming short column action, so as to ena%le it to carr& a4ial com$ression arising (rom (actored gra!it& load and lateral seismic shaking e((ects*
10..2.1 The load (actor (or gra!it& load shall %e taken as 5*, i( gra!it& load gi!es higher a4ial com$ressi!e strength o( the %oundar& element* /5*+*3The !ertical rein(orcement in the %oundar& elements shall not %e less than 5* $ercent and not greater than - $ercent; the $ractical u$$er limit #ould %e + $ercent to a!oid congestion*
a"
area o( this diagonal rein(orcement along each diagonal shall %e estimated as. " sd
* u
=
,
/*0+ f & sin α
Where * u is (actored shear (orce on the cou$ling %eam and the angle made % & diagonal rein(orcement #ith the hori)ontal* %" at least + %ars o( mm diameter shall %e $ro!ided along each diagonal* ll longitudinal %ars along each diagonal shall %e enclosed %& s$ecial con(ining trans!erse rein(orcement as $er / at a s$acing not e4ceeding /55 mm*
10..3 The diagonal o( a cou$ling %eam shall %e anchored in the ad6acent #alls #ith an anchorage length o( /*B times the de!elo$ment length in tension see Fig* /-"*
10.6O5e!)!+s )! a%%s
/5*+*+ 'oundar& elements, #here required as $er /5*-*/ Shear strength o( a #all #ith o$enings should %e 10..1 , shall %e $ro!ided #ith s$ecial con(ining checked at critical hori)ontal $lanes $assing through rein(orcement throughout their height, gi!en %& o$enings* /5*-* dditional steel rein(orcement shall %e $ro!ided
"sh h
= 5*5B s!
f ck f &
along all (our edges o( o$enings in #alls* Further, a"
the area o( these !ertical and hori)ontal steel should %e equal to that o( the res$ecti!e
FI8* /- CO<2=I>8 'E7S WIT DI8O>= R EI>FORCE7E>T interru$ted %ars, $ro!ided hal( on either side o( the #all in each direction* these !ertical %ars should e4tend (or (ull height o( the store& in #hich this o$ening is $resent* c" the hori)ontal %ars should %e $ro!ided #ith de!elo$ment length in tension %e&ond the edge o( the o$ening*
%"
the la$ length shall not %e less than the de!elo$ment length o( the largest longitudinal rein(orcement %ar in tension*
c"
la$ s$lices shall %e $ro!ided onl& in the central hal( o( clear #all height, and not,
%"
10.7 Co!s(&)o! >o)!&s @ertical rein(orcement across a hori)ontal construction 6oint shall ha!e area, "st gi!en %&. "st "g
≥
u τ − ! "g
5*9 f &
#here τ! is (actored shear stress at the 6oint, u (actored a4ial (orce $ositi!e (or com$ression", and "g gross crosssectional area o( 6oint*
10./=e'e%o5me!&- S5%)(e a!" 8!(o#a+e Re;)#eme!& /5**/ ori)ontal rein(orcement shall %e anchored near the edges o( #all or in con(ined core o( %oundar& elements* /5** In slender #alls 3I'# M ", s$licing o( !ertical (le4ural rein(orcement should %e a!oided, as (ar as $ossi%le, in regions #here (le4ural &ielding ma& take $lace, #hich e4tends (or a distance larger o( a" '# a%o!e the %ase o( the #all; and %" /A-th o( the #all height; %ut not larger than 4'#* /5**3 Splices /5**3*/ 'ap splices When ado$ted, closed links shall %e $ro!ided o!er the entire length o!er #hich the longitudinal %ars are s$liced* Further,
/"
#ithin a 6oint; or
#ithin a distance o( d (rom a location #here &ielding o( rein(orcement is likel& to take $lace* d" not more than B5 $ercent o( area o( steel %ars shall %e s$liced at an& one section* "
10./.3.2 7echanical cou$lers con(orming to IS /-/0" shall %e used* Further, onl& those mechanical s$lices con(orming to the a%o!e standard and ca$a%le a" the s$acing o( these links shall not e4ceed /B5 mm*
o( de!elo$ing the s$eci(ied tensile strength o( s$liced %ar shall %e $ermitted #ithin a distance equal to t#o times the de$th o( the mem%er (rom the %eamcolumn 6oint or in an& location #here &ielding o( rein(orcement is likel& to take $lace
10./.3.3 elded splices
Welding o( links, ties, inserts or other similar elements to !ertical rein(orcement %ars required as $er design is not $ermitted, in an& seismic )one*
10./. In %uildings located in Seismic ?ones II and III, closed loo$ trans!erse links shall %e $ro!ided around la$$ed s$liced %ars larger than /- mm in diameter* The minimum diameter o( such links shall %e /A+th o( diameter o( s$liced %ar %ut not less than mm at s$acing not e4ceeding /B5 mm centres.
11 GR8ITY COL
IS 13920 : 2016
a((o#")!+ &o 11.1 a!" 11.2 *o# e!")!+ mome!&s )!"(e" e! s?e(&e" &o DRD &)mes &e "es)+! %a&e#a% ")s5%a(eme!& !"e# &e *a(&o#e" e;)'a%e!& s&a& 11.1.2 G#a')&$ (o%m!s )& *a(&o#e" +#a')&$ a)a% sess e(ee")!+ 0.* ( sa%% sa&)s*$ 11.1.1 a!" sa%% a'e a!s'e#se #e)!*o#(eme!& a& %eas& o!e a%* o* s5e()a% (o! %o!+)&")!a% a# o# 10 mm. //*/ The $ro!isions in 11.1.1 and 11.1.2 shall %e //* When induced %ending moments and shear (orces satis(ied, #hen induced %ending moments and under said lateral dis$lacement com%ined #ith hori)ontal shear (orces under the said lateral (actored gra!it& %ending moment and shear (orce dis$lacement com%ined #ith (actored gra!it& %ending e4ceed design moment and shear strength o( the moment and shear (orce do not e4ceed the design (rame, 11.2.1 and 11.2.2 shall %e satis(ied* moment o( resistance and design lateral shear ca$acit& o( the column* 11.2.1 7echanical and #elded s$lices shall 7.3.2.2 satis(& and 7.3.2.3. //*/*/ 8ra!it& columns shall satis(& 7.3.2, 7..1 and //** 8ra!it& columns shall satis(& 7. and /* 7..2. 'ut, s$acing o( links along the (ull column height shall not e4ceed - times diameter o( smallest
8NNE 8 Clause /5*3*/" 8,1 MOMENT OF RESIST8NCE RECT8NG
β =(
OF
(
) < ( ,N
u
M u ck # #
t
#
)
u
'
#
u
#
f ck t # '# #here
) < /*5
−α − u −α u
=α
'# /
'#
ϕ α = 5*/B + /− β + 3 − 3β and
; /
λ
3
β / α/ = 5*3- + ϕ /− − β β /
#here
=
) < (
M u
#
/ λ 5*+/- u / = ϕ + − ' ϕ #
ϕ+λ
For ' ( ,N ' u
u β − ' 5*/- + 3 #
u
,
5*553 B
u G (actored com$ressi!e a4ial (orce on #all*
%"
For '
)
& s G elastic modulus o( steel, and
The moment o( resistance M u o( a slender rectangular structural #all section #ith uni(orml& distri%uted !ertical rein(orcement ma& %e estimated as.
a"
5*55 + 5*0 f & & s
ϕ+ 5*3-
'#
α3 = ϕ
N
u
=
5*553 B
(
5*553 B + 5*55 + 5*0 & s f & ; 5*0 f & ρ ϕ= f ck ; '#
− 3 *
/
-β
' u
uA '# to %e used in this e4$ression shall %e o%tained %&
)
sol!ing the equation.
α/ + α+ u − αB = 5 # ' '# #here ϕ α = − λ , and
( λ = u ; "st f ck t # '# , ρ G !ertical rein(orcement ratio G
u
t ' # #
β ϕ αB = β* +
"st G area o( uni(orml& distri%uted !ertical rein(orcement,
/9
8NNE B Foreord " COMMITTEE COMPOSITION Earthquake Engineering Sectional Committee, CED 39 Chairman DR D* K* 2<= Indian Institute o( Technolog& Roorkee, Roorkee rgani5ation
Representative(s)
ssociation o( Consulting Ci!il Engineers, 'angalore
SRI S>DEE2 SIRKEDKR DR SWT 7* <* "lternate"
tomic Energ& Regulator& 'oard, 7um%ai
DR =* R* 'IS>OI SRI R OS> * D* "lternate"
'harat ea!& Electricals =imited, >e# Delhi
SRI R @I K <7R
'uilding 7aterials Technolog& 2romotion Council, >e# Delhi
SRI :* K* 2RSD SRI 2>K: 8<2T "lternate"
CSIRCentral 'uilding Research Institute, Roorkee
DR >@:EE@ SJE> DR :H C
CSIR>ational 8eo$h&sical Research Institute, &dera%ad
DR 7* R @I K <7R DR >* 2C>DR R O "lternate"
CSIRStructural Engineering Research Centre, Chennai
DR >* 8O2=KRIS>> DR K S K RIS>7OORTH "lternate"
Central 2u%lic Works De$artment, >e# Delhi
SRI *K* 8R8 SRI R :ES K RE "lternate"
Central Soils and 7aterials Research Station, >e# Delhi
SRI >RI2E>DR K <7R DR 7>IS 8<2T "lternate"
Central Water Commission, >e# Delhi
DIRECTOR , C7DD E >E" DIRECTOR , E7'>K7E>T "lternate"
Creati!e Design Consultants Enginee rs 2!t =td, 8ha) ia%ad
SRI 7>DEE2 8R8 SRI 'R:I>DER SI>8 "lternate"
DCD Technologies, >e# Delhi
DR K* 8* 'TI
DDF Consultants 2!t* =td, >e# Delhi
DR SRI7TI " 2RTI7 R* 'OSE SRI SD>>D O: "lternate"
Directorate 8eneral o( 'order Roads, >e#
Delhi
SRI '* S* 2>DEH
Engineers India =imited, >e# Delhi
7S I= DSS DR 8 8 SRI>I@S CRH "lternate"
8ammon India =imited, 7um%ai
SRI @* >* E88DE SRI >>D DESI "lternate"
8eological Sur!e& o( India, =uckno#
SRI K* C* :OSI
ousing e# Delhi
SRI S7IR 7ITR
Indian Concrete Institute, Chennai
DR * R* S>TK<7R
Indian Institute o( Technolog& 'om%a&,
7um%ai
DR R @I SI> DR =OK 8OH= "lternate"
Indian Institute o( Technolog& 'hu%anes#ar, 'hu%anes#ar
DR S:> DS
Indian Institute o( Technolog& 8u#ahati, 8u#ahati
DR E7>T '* K
Indian Institute o( Technolog& :odh$ur, :odh$ur
DR C* @* R* 7
Indian Institute o( Technolog& Kan$ur, Kan$ur
DR D
Indian Institute o( Technolog& 7adras, Chennai
DR * 7EER 2RSD DR R <2E> 8OSW7I "lternate I" DR R<> 7E>O> "lternate II"
Indian Institute o( Technolog& Roorkee,
2ROF SOK :I> DR 7>IS SRIK>DE "lternate"
Roorkee
IS 13920 : 2016 rgani5ation
Representative(s)
Indian Institute o( Technolog& 8andhinagar, 8andhinagar
DR S* K* :I>
Indian Institute o( In(ormation Technolog&,
DR 2RDEE2 K <7R R 7>CR=
&dera%ad
Indian 7eterological De$artment, >e# Delhi
SRI S
Indian Roads Congress, >e# Delhi
SECRETRH 8E>ER= DIRECTOR "lternate"
Indian Societ& o( Earthquake Technolog&, Roorkee
2ROF * R* WSO> 2ROF 7* =* SR7 "lternate"
7ilitar& Engineer Ser!ices, EngineerinChie(1s 'ranch, >e# Delhi
'RI8* '* D* 2>DEH SRI R @I SI> "lternate"
>ational Council (or Cement and 'uilding 7aterials, 'alla%garh
SRI @* @* ROR
>ational Disaster 7anagement uthorit&, >e# Delhi
DR R @I>DER SI>8
>ational Thermal 2o#er Cor$oration, >oida
DR 2R@EE> K >DE=W= SRI S
>uclear 2o#er Cor$oration o( India =imited, 7um%ai
SRI R@I>D SRI@ST@ SRI R 8<2TI R OH "lternate"
Research, Design and Standards Organi)ation, =uckno#
SRI 2IH
Risk 7anagement Solutions Inc R7SI", >oida
SRI S
RITES =imited, 8urgaon
SRI * K* 7T
Tandon Consultants 2!t =imited, >e# Delhi
2ROF 7ES T>DO> SRI @I>H K* 8<2T "lternate"
Tata Consulting Engineers, 7um%ai
SRI K* @* S<'R7>I> SRI '* '* 8RT "lternate"
@akil7ehtaSheth Consulting Engineers, 7um%ai
7S =2 R* SET SRI R* D* C
@is!es!ara&a >ational Institute o( Technolog&,
DR O* R* :ISW= DR R* K* I >8=E "lternate"
Wadia Institute o( imala&an 8eolog&,
>ag$ur
Dehradun
In $ersonal ca$acit&, '1674, %esign "rch, Sector18, *aishali, 9a5ia#ad 47: 7:7"
DR S
e13omes,
2ROF *S* RH
In $ersonal ca$acit&, :;
DR S* K* TKKR
In $ersonal ca$acit&, >=, ld Sneh Nagar, ardha Raod, Nagpur <<7 7:8"
SRI =* K* :I>
In $ersonal ca$acit&, ?1'I4 ?avi Nagar, 9ha5ia#ad 47: 774"
DR * K* 7ITT=
In $ersonal ca$acit&, 5/+A , Sarasati ?un+, IIT Roor2ee, Roor2ee 4<; ==; "
DR I* D* 8<2T
In $ersonal ca$acit&, Flat No. 447, "n2ur "partments, Mother %air! Road, atpar 9an+, %elhi, ::7 7@4"
DR @* TIR<@E>8D7
'IS Directorate 8eneral
SRI '* K* SI>, Scientist 1E1 and ead Ci!il Engg" PRe$resenting Director 8eneral &1officio"Q Mem#er Secretar! SRI S* R<> K <7R Scientist 1D1 Ci!il Engg", 'IS
Continued from second cover "
c"
estimating the design moment o( resistance o( structural #alls #ith %oundar& elements* Instead, $rocedure is mentioned (or estimating the same* dditional signi(icant modi(ications incor$orated are as under . /" The detail o( anchorage o( longitudinal %eam %ars at e4terior %eamcolumn 6oint has %een re!ised see 6.2."* 24 Clauses gi!ing detail a%out mechanical cou$lers, #elded s$lices in %eam, column and shear #all ha!e %een added see 6.2.6.2- 6.2.6.3- 7.3.2.2- 7.3.2.3- 10./.3.2 and 10./.3.3 ". 3" The minimum diameter o( a link has %een changed to mm in all cases see 6.3.2"* +" The (actored a4ial com$ressi!e stress consisting o( all load com%inations related to seismic loads is limited to 5*+5 f c2 has %een added see 7.1"*
The minimum dimension o( a column has %een modi(ied to 5 d # or 355 mm see 7.1.1"* The minimum dimension o( a column has %een modi(ied to 5 d % or 355 mm see 7.1.1"* The e4$ression (or area o( cross section " sh (or the %ars (orming circular and rectangular links or s$iral ha!e %een modi(ied P see /.1c"Q* " Design o( %eamcolumn 6oints o( moment resisting (rames has %een added and e4$ressions (or e!aluating nominal shear strength is also gi!en see 9.1.1"* 9" E4$ression (or calculating s$ecial con(ining rein(orcement in %oundar& element in shear #all is added see 10.. "* /5" (igure sho#ing rein(orcement detail o( cou$led shear #all #ith diagonal rein(orcement has %een added see 10..3 "* Further, #hile the common methods o( design and construction ha!e %een co!ered in this standard (or RC structural s&stems #ith moment resisting (rames and RC structural s&stems #ith structural #alls that $artici$ate in resisting earthquake (orce, design and construction o( other lateral load resisting structural s&stems made o( rein(orced concrete %ut not co!ered %& this standard, ma& %e $ermitted %& the a$$ro!ing agenc& or a Committee constituted %& the agenc& onl& on $roduction o( satis(actor& e!idence (rom e4$eriments on $rotot&$e su% assem%lages and structures, and nonlinear anal&ses demonstrating their adequac& to resist earthquake shaking e4$ected in the region #here the structures are e4$ected to %e %uilt* Such nonlinear anal&ses shall demonstrate that the colla$se mechanism o( the $ro$osed structure is desira%le and that the lateral de(ormation ca$acit& o( the structure is su((icient to resist the ground de(ormation im$osed in the region #here the structure is located* The Committee o( the a$$ro!ing agenc& shall com$rise o( com$etent engineers #ith the necessar& e4$erience and shall ha!e the authorit& to re!ie# the data su%mitted, ask (or additional data, tests and to (rame s$ecial rules (or such structural s&stems not co!ered under this Code* B" -" 0"
The Committee res$onsi%le (or the (ormulation o( this standard has taken into consideration the !ie#s o( manu(acturers, users, engineers, architects, %uilders and technologists, and has related the standard to the $ractices (ollo#ed in the countr& in this (ield* lso, due #eightage has %een gi!en to the need (or international coordination among standards $re!ailing in di((erent seismic regions o( the #orld* In the (ormulation o( this standard, assistance has %een deri!ed (rom the (ollo#ing $u%lications. CI 3///, 1'uilding code requirements (or structural concrete and commentar&1, issued %& merican Concrete Institute* I'C 5/ 1International 'uilding Code1, $u%lished %& International Code Council, Inc* $rE> /99/ . 55BE" Eurocode . 1Design o( structures (or earthquake resistance 2art /. 8eneral rules, seismic actions and rules (or %uildings1, issued %& Euro$ean Committee (or Standardi)ation, 'russels* >?S 3/5/2art /" . 55- 1Concrete structures standard1, issued %& Standards Council, >e# ?ealand*
3
The com$osition o( the Committee res$onsi%le (or the (ormulation o( this standard is gi!en at nne4 '* For the $ur$ose o( deciding #hether a $articular requirement o( this standard is com$lied #ith, the (inal !alue, o%ser!ed or calculated, e4$ressing the result o( a test or anal&sis, shall %e rounded o(( in accordance #ith IS . /9-5 1Rules (or rounding o(( numerical !alues revised "1* The num%er o( signi(icant $laces retained in the rounded o(( !alue should %e same as that o( the s$eci(ied !alue in this standard*
B#ea o* I!")a! S&a!"a#"s 'IS is a statutor& institution esta%lished under the $ureau of Indi an Standards "ct , /9- to $romote harmonious de!elo$ment o( the acti!ities o( standardi)ation, marking and qualit& certi(ication o( goods and attending to connected matters in the countr&*
Co5$#)+& 'IS has the co$&right o( all its $u%lications* >o $art o( these $u%lications ma& %e re$roduced in an& (orm #ithout the $rior $ermission in #riting o( 'IS* This does not $reclude the (ree use, in the course o( im$lementing the standard, o( necessar& details, such as s&m%ols and si)es, t&$e or grade designations* Enquiries relating to co$&right %e addressed to the Director 2u%lications", 'IS*
Re')e o* I!")a! S&a!"a#"s mendments are issued to standards as the need arises on the %asis o( comments* Standards are also re!ie#ed $eriodicall&; a standard along #ith amendments is rea((irmed #hen such re!ie# indicates that no changes are needed; i( the re!ie# indicates that changes are needed, it is taken u$ (or re!ision* o*. CED 39 09+/"*
8me!"me!&s Isse" S)!(e P%)(a&)o! mend >o*
Date o( Issue
Te4t ((ected
'DI> ST>DRDS
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