(6 3 )

( ): c=1.5, s=1.15 g=1.35 (1.00), q=1.5 (0.00) /: 25 kN/m3; fcd = fck/c (MPa); fyd = fyk/s (MPa); fcm = fck+8 (MPa); Ecm = 9.5(fck+8)

1/3 (GPa); fctm = 0.3fck2/3 (MPa)

fctk0.05 = 0.7fctm (MPa); Rd = 0.25fctk0.05/c (MPa); fc1=fck+4.13; co1=co(1- 3/fck); Es = 200 GPa

(mm) 8 10 12 14 16 18 20 22 22

s (mm2) 50.3 78.5 113 154 201 254 314 380 491

: 1 2 3 4 : - 5 mm

cmin (mm) = 20 25 30 30-45 cnom = cmin + 5 (mm)

, , &

: fbd = 1234fctk0.05/c : 1 = 1 = 2.25 2 = 1 = 0.7 ( : )

3 = 1 30 = (132-)/100 > 32. 4 = 1 () = 1.4 3 .

: fb = fs/4b . , fb = dM/(jddx) = V/(jd)

: max (max, 20mm, d.+5mm) , : d. : .

: b = (/4)(fyd/fbd) : b,net = b(As,cal/As,eff) b,min , = 1 , = 0.7 (i) (ii) . : As,cal/As,eff = 1.

: b,min = max(0.3b 0.6b , 10)

: 25% .

: Ft = Vsda/d 0.5Vsd. : b 0.66 b,net.

b,min.

5 .

( ): o = a1b,net max(0.3a1b, 15, 200 mm) (.) o = b,net (). : 1.5o, & 0.3o .

a1: :

&

%

20% 25% 33% 50% >50% 10 5 1.2 1.4 1.6 1.8 2.0

> 10 > 5 1.0 1.1 1.2 1.3 1.4

75%

(DA) , (D) S220 S400, S500 S220 S400, S500

< 20 mm 2.5 4.0 c. > 100 mm > 7 10 10

20 mm 5.0 7.0 c. > 50 mm > 3 10 15

c. 50 mm 3 15 20

: 5 (10 )

:

mmd.s

);acot(d.s

f/f.

max,t

max,b

ykckmin,w

600750

1750

080

&

(+)

: : c < 0.002, cd=0.85fcd1000c(1-250c); 0.0020< c < 0.0035, cd=0.85fcd. : yd=fyd/Es, : s < 0.0035 (), s < 0.020 ()

: =c/x = s1/(d-x). x=[c/(c+ s1)]d = d (y) = y. bal = 0.0055/d; xbal=0.64d; bal=0.64

Fc=db0.85fcd; =1000c(6-1000c)/12, c 0.45. : R=MR/bd2fcd=R(ycg/d)-[0.85(0.4)-( s1-s2(d2/d))fyd/fcd]

: R0.266, s10.33fcd/fyd. s1,bal =0.435fcd/fyd. x=1.47s1fyd/fcdb. R= 0.68(1-0.4),

R= s1(fyd/fcd)(1-0.58s1(fyd/fcd)). : R= limbd2+MR. s2=Rfcd/fyd[1/1-(d2/d)].

: s1bd-NSd/fyd. e=MSd/NSd. : Rd,crush=0.85fcd(Ag-As)+Asfyd

: Rd,tension=Asfyd

: : bef = bw+o/5 : bef = bw+o/10 (: bw = ) o = 0.3 ( ), 0.6 ( ), 0.8 ( ), 1.5 (). : = n + ti n = ti = 0.5t t, ti = min (t/3, 0.025n) - t ti = min (t/2, 0.025n) - t.

: < lim,f = hf/0.8d; lim,f=0.68(hf/0.8d)(1-0.5hf/d); Rd=MRd/beffd2fcd< lim,fAs1= s1beffd; ,

w= MRd-lim,fbeffd2fcd, w=/bwd

2fcd

cotfzs

AV

tancot/fvzbV

ywd

sw

s,Rd

cdwmax,Rd

: q=M(A/)/[jd(o/2)]. vRd2=2fcdhf. vRd3=(Asf/s)fyd,f+2.5Rdhf (vc=0 . ). sf,min=Asf/sh (.)

: 1,2=0.5(x+y)[(x-y)2/4+2]1/2. Ls=Mmax/V. VEd>VRd,C VEd < {VRd,s, VRd,max}

VRd,C = [CRdk(100fck)1/3+0.15cp]bwd

(+)

:

:

:

:

realef tc2u

At

cotA2

T

s

A

k

Edywd

sw f

),min(

cot175.0

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hb

d

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s

w

:

:

350 mm

002.0232

243

002.064

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c

cc

cc

c

c

c

002.03

23

002.012

6

c

c

c

ccc

yd

d

yd

cds

NdbA

ff

f

yd

cd

2

imsd2s db

dd1A

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yd

cd

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imsdim1s

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dd1A

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f

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dh601.0

8051

1

min ykim f

imimim 286.0688.0 cd

2

sdsd

db

M

f

(+) (CEB)

1. CEB

2. CEB S220

2. CEB S400

2. CEB S500

1. : 2. : yd

d

yd

cds

NdbA

ff

f

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cd22s

yd

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yd

cd11s dbA

NdbA

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1 2