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Reinforced and Prestressed Concrete -c7 -

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+ if a. < 0,5rl11e valre c,,: 0,5d should be ued

tr--;--lI B=:-lI' zdl

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t-.---''-''-rlr.atpa:r pa -4-rq + (}Jl d-ad,,*J =!-Ed * Ll'u * 4' { a, + d }

,-!

wtrKaatufig3arr

fhe additisaal tensile force, A{,o, ia fhe longitudiml

rehforcement due to shear force I/p; is:

'ltlh,, Yro I I

lFi - section considered

l

The anchorage length fu is measured frsm the linE ol contact betwe€fibearn and support. Transverse pressure may bp takpn into aceour* tor direct support,

r.q ja) Direcr support Beam supporiad by bl hafirect support: Beam inteEecling another

mll or slumn suppoiting beam

fo = gr dzfi3 s4 di(u,.qorb 6.mia &.m b the minimum anchorage leng& if no other limilalisn is epplied;- for anchoreges i$ tension: l6p;q > max{0,36.qd; 10fr 100 mm}- lor anchoragies in compression: [6h > rnax{0,616,qgi 104 100 mm}

= {95i 4} (o"a/ f66}

The design value of ihe ultimate bond stress, ,id, for ribbed barsfi,.= 2.25 4t 4t fa

ferd is the design value of concrete lensile slrengthfa16 = aqt fd13.05 J;6

41 is a coefficient relaied to the quality of the bond condition and the position of the barduring concreting:41 = 1,0 when 'good' eonditions are obtained and41 = 0,7 {or all olher cases and for bars in shuctural elements built with slipfonns,un{ess it can be shovrn thal 'gocd' bond conditions exist

rJ2 is r€lated to the bar diameter:?=1,0forgt:32mm42= {'132 - gil100 for d > 32 mm

al ,l5o<ds90{ c} lr>250mm EDirstion ot cg*creting

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?

-Ao '' 'd, +\r\\\\\\\\)r.

latIt,

t-hl "= 2-l-

b) 'l<250mm

latched zore - 'Bod' bmd condmoffi

tfgn-'Ed *i 1.1y*

Lar = s.5o ' z' { ctg F- ctg a')

fortransversalreinforcement: ctgt{= Q md }/r, =fiValres ot gL dr, dj, (l1 and g5 coefnciants

g! e 0,7 if cd >34totheMi* {1 = 1,0

Olher than stmight(se Fbure 8.1 {b),(c) and (d))

Coafin€ment by*ansveseptssure

ltfi-Galffi

) = {IAc- I4*,nin} As

lAst cross-sectiqnal ar€a of the transverse rein$orcement along the design anchoragelength {,a

.'A$tmin cross-s€ctional al€a of the minimum transverse reinforcernent= 0,25 As for beams and 0 for slabs

As area of a single anchored bar with maximum bar diameterp transverse pressure [MPa] at ultirnate limit state along lbd

A. d,. A. A. 4, Ao

lV/" --r-i--K - 0,1 l{ = 0,05

a)straightbars blBentorhoo*edbars clLoopedbaricd = min {a12, t,, c} cd= mifi {aQ, ci cd= c

Anchorage of links and shear rcinforeer$ent

The anchorage of links and shear reinforcement should normally be effected by means ofbends and hooks, or by welded transverse reinforcement- A bar should be provided inside aho6k or bend,

50,but) 50 mrn

N{'@

1Od, but>g' l:Iff.*

f >rommarfissomm

$ > o.7d Fr{o It

)10 mm

lnrlFf > 1,4r

I

{'rl)@ c)

HEte: For c) and d) the corer ihauH nol beless than either 3d or 50 nKn-

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Anchorage of bottom reinforcement at intermedlate supports

The anchorage lengilh shauld not be less lhan 109 ffor straight bars) or not less than thediarneter of the mandrel {for hooks and bends with bar diameten at least equal to 16 mm) ortwice the diameter of lhe rnandrel {in olher casesi {see Figure {a}).The reinforcement required to resist possible positive moments {e.9. seftlement o{ thesuppo*, explosion, etc.) should be continuoss which may be achieved by meansof lapped bars {see {b} or {ci}.

/* ,fu

a) b,

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Shear reinforcement

The shear reinforcement should form an angle a of between 45" tnd 90" to the longitudinalaxis o{ the structural eiement,

The shear reinforcemeilt may consist of a clmbination of:- links enclosing the longitudinaltension reinforcement and the compression zone- benlq:p bars;- cages, ladders, etc. rphich are casl in wi&out enclosing the longih.dinal reinforcement but

are prcperly anchored in the compression and tension zones.

At least 5oqi of the necessary shear reinforcement should be in the form of iinks.

iln #$milmarginal

opened link

il[interiorlirks

inteJistlink

closed link

!16**ffi

The ratio of shear reinforcernent

/r*=A*/(s.b*.sina)whete:

pw is the shear reinforcement ratiop* should not be less than p*.*

4"" is the area of shear reinforcement within length ss is ths spacing of the shear reinforcement measured along the longitudinal axis ol

the memberb* is the bresdlh of the web of the membera is the angle between shear reinforcement and the longitudinal axis

p_"* ={0,08r,f,)/f,r

il the potartial plalic zones of the beuns" iu seisnic zoues with ds i 0.I2.g -

The maximum longitudinal spacing between sh6ar assemblies should nol exceed st,md.

srm" =0,75d{1 + coto ) < 300mm

d is th€ inclinalion of th€ shear r€|inforcement lo the lonEitudinBl 6xis of fte fleam,

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S'Sa*o {'la,*- 'f. li

{ 300rnm

" S,sr,,*

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't!

t

< 600 mm\di.&

;3-*

The maximum longihrdinal spacing of bent-up bars should not excead sb.ffi:e =0-6d{1 +ccttd)4R

Tha transv€rss spacing of lhe legs in a series of shear links sho'uld ntt exceed q;:' st s'= 0,75d 5 S00mm

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'lr,W,t''.lfirl-(*ffil

.a.t'.

t.,

*tg0 o2 rY*.*=1-200"325-0J4'16,57.*+ = ?34,0-ld N =234,0 kl{ > ps,**

2+j4zg.,r = *= 1ffi * 0,0o1415 >P".ffi =0,0009P

tie $ensile fsrcs in the lonsitudi$al reipforcensnts;

I Y-. --a.iFu='u't -t *Na, =92,07'ld NlL_a_l

(a, =gJr{dgd- aga!-g5s.qg.*$)az , crga=0 , Nsd=0}..

ihe tensilp shess ill lhe lollgifudinql reisfore€rEe[ts:

F" 92.07.td6-, = -J-3- = lill---ll- = 126,8 N/run'?-' a*.s 726

i4..a = 0,25 l8'# = 2t t *rn'_-* ,'.j