8.1.1 ( ) , .
8.1.20 - 8.1.30.
:
, , , 8.1.4 - 8.1.16;
- .
8.1.2 , , .
, l 0/ i > 14 e 0 η, 8.1.15.
8.1.3 , (. 8.2.8 - 8.2.14), 15 %, .
8.1.4 , , :
;
, Rb ;
() ;
Rs;
Rsc.
8.1.5 , , ξ R, , Rs.
8.1.6 ξ r
(8.1)
ε s,el - , Rs
(8.2)
ε b 2 - , Rb, 6.1.20.
70 - 100 (8.1) 0,8 0,7.
|
|
8.1.7 0 , :
1/600 , ;
1/30 ;
10 .
0 , , .
0 .
8.1.8
£ ult, (8.3)
- :
Mult - , .
8.1.9 lt ( 8.1)
Mult = Rb × b × x (h 0 - 0,5 x) + Rsc × A's × (h 0 - a'), (8.4)
0138S10-03623
(8.5)
8.1.10 Mult , ( ), :
) ( 8.2, ), ..
Rs × As £ Rb × b'f × h'f + Rsc × A's, (8.6)
Mult 8.1.9 b'f;
) ( 8.2, ), .. (8.6) , Mult
Mult = Rb × b × x (h0 - 0,5 x) + Rb (b'f - b) h'f (h 0 - 0,5 × h'f) + Rsc × A's (h 0 - a'),(8.7)
0138S10-03623
(8.8)
0138S10-03623
8.1 - , ,
0138S10-03623
8.2 -
8.1.11 b'f, , , 1/6 :
) h'f ³ 0,1 h - 1/2 ;
) ( , ) h'f < 0,1 h - 6 h'f;
) :
h'f ³ 0,1 h........................... 6 h'f;
0,05 h £ h'f < 0,1 h............. 3 h'f;
h'f < 0,05 h - .
8.1.12 x £ξ R × h 0.
, , x £ξ R × h 0, Mult (8.4) (8.7), x =ξ R × h 0.
|
|
8.1.13 , Rs × A = Rsc × A's, ult
Mult = Rs × As (h 0 - a'). (8.9)
(A's = 0) < 2 ', (8.9) ' x /2.
8.1.14
N × e £ Rb × b × (h 0 - 0,5 ) + Rs × 's (h 0 - a'),(8.10)
N - ;
- N ( ) ,
(8.11)
η - , () 8.1.15.
e 0 - 8.1.7.
:
) ξ = x / h 0 £ ξ R ( 8.3)
0138S10-03623
(8.12)
) ξ = x / h 0 > ξ R
0138S10-03623
(8.13)
0138S10-03623
8.3 - , ,
8.1.15 η
(8.14)
N - ;
Ncr - ,
(8.15)
D - , ;
l 0 - , 8.1.17.
D
D = kbEbI + ksEsIs,
b, Es - ;
I, Is - , ;
ks = 0,7;
φ l - , φ l = 1 + Ml 1/ M 1, 2.
1, l 1 - ( ) ;
δ - e 0/ h, 0,15 1,5.
η , .
8.1.16 ,
, 0 £ h /30 l 0/ h £ 20
N £ Nult,(8.16)
Nult - , ,
Nult = φ × (Rb × A + Rsc × As,tot). (8.17)
- ;
As.tot - ;
φ - , 8.1 ; φ , φ = 0,9 l 0/ h = 10 φ = 0,85 l 0/ h = 20.
8.1
φ l 0/ h, | ||||
20 - 55 | 0,92 | 0,9 | 0,83 | 0,7 |
60 | 0,91 | 0,89 | 0,80 | 0,65 |
80 | 0,90 | 0,88 | 0,79 | 0,64 |
8.1.17 l 0 , .
|
|
l 0 / :
) - 1,0 l;
) ( ) () - 2,0 l;
) , :
( ) - 0,7 l;
( ) - 0,9 l;
) ( ) , :
( ) - 1,5 l;
( ) - 2,0 l;
) :
( ) - 0,5 l;
( ) - 0,8 l;
) : ( ) - 0,8 l;
( ) - 1,2 l.
8.1.18
N £ Nult,(8.18)
N - ;
Nult - , .
Nult
Nult = Rs × As,tot, (8.19)
As,tot - .
8.1.19 N:
) N S S' ( 8.4, ) -
N × e £ Mult;(8.20)
N × e' £ M'ult,(8.21)
N × e N × e' - ;
ult M'ult - , .
ult M'ult
ult = Rs × A's (h 0 - a'); (8.22)
'ult = Rs × As (h 0 - a');(8.23)
) N S S' ( 8.4, ) - (8.20), ult
ult = Rb × b × x (h 0 - 0,5 x) + Rsc × A's (h 0 - a'), (8.24)
0138S10-03623
(8.25)
(8.25) > ξ R × h 0, (8.24) x = ξ R × h, ξ R 8.1.6.
0138S10-03623
- S S'; - S S'
8.4 - , , N
8.1.20 , , , , :
|
|
( );
() .
, ε bi ³0 σ bi = 0. (, , ) .
8.1.21 . : () - ; () - . ().
8.1.22 :
, ;
, .
, Y. ( 0 8.5) .
0138S10-03623
8.5 -
8.1.23 (. 8.5) :
:
0138S10-03623
(8.26)
0138S10-03623
(8.27)
0138S10-03623
(8.28)
,
0138S10-03623
(8.29)
0138S10-03623
(8.30)
,
σ bi = b × vbi × εbi;(8.31)
σ sj = sj × vsj × εsj;(8.32)
(8.26) - (8.32):
, My - ( XOZ YOZ ), :
Mx = Mxd + N × ex;(8.33)
My = Myd + N × ey;(8.34)
Mxd, Myd - , ;
N - ;
ex, ey - N ;
bi, Zbzi, Zbyi, σ bi - , i - ;
sj, Zsxj, Zsyj, σ sj - , i - ;
ε0 - , ( 0);
1/ rx, 1/ ry - ;
b - ;
Esj - j - ;
vbi - i - ;
vsj - j - .
vbi vsj , 6.1.19, 6.2.13.
vbi vsj , , b s ( - b,red). - (6.5) - (6.9), (6.14) (6.15) .
(8.35)
(8.36)
8.1.24 :
|ε b,max | £ ε b,ult;(8.31)
ε s,max £ ε s,ult,(8.38)
|
|
ε b,max - ;
ε s,max - ;
ε b,ult - , 8.1.30;
ε s,ult - , 8.1.30.
8.1.25 , ( 8.5), ε b,max ε s,max (8.39) - (8.41) (8.29) (8.30)
0138S10-03623
(8.39)
0138S10-03623
(8.40)
0138S10-03623
(8.41)
Dij (i,j - 1, 2, 3) (8.39) - (8.41)
0138S10-03623
(8.42)
0138S10-03623
(8.43)
0138S10-03623
(8.44)
0138S10-03623
(8.45)
0138S10-03623
(8.46)
0138S10-03623
(8.47)
- . 8.1.23.
8.1.26 , ( ), (8.41) N = 0.
8.1.27 X = 0 D 12 = D 22 = D 23 = 0. :
0138S10-03623
(8.48)
0138S10-03623
(8.49)
8.1.28 X N = 0, = 0 D 12 = D 22 = D 23 = 0. :
0138S10-03623
(8.50)
0138S10-03623
(8.51)
8.1.29 (8.37) 8.1.24 - 8.1.28, 8.1.25 Dij Asj = 0.
, ,
ε bt, max £ ε bt,ult, (8.52)
ε bt, max - , 8.1.25 - 8.1.28;
ε bt,ult - , 8.1.30
8.1.30 ε b,ult (ε bt,ult) ( ) (, ) ε b 2(ε bt 2).
ε b,ult (ε bt,ult) ε1 ε2 (|ε2| ³ |ε1|) :
0138S10-03623
(8.53)
0138S10-03623
(8.54)
ε b 0, ε bt 0, ε b 2 ε bt 2 - (6.1.14, 6.1.20, 6.1.22).
ε s,ult :
0,025 - ;
0,015 - .