Ncr ,
l0
D .
:
, ( )
I Is ;
φl ,
φl = 1+ M l l / 1
2;
M 1 M 1 l , ( ) , ;
δ - , 0/h, 0,15 ( h D cir);
15-35 , ,
0 = h/ 30, l0 < 20 h
N< φ (RbA + RscAs,tt),
φ - , l0/h.
0.85 0.9.
, , .
,
Rs,xy
nx, Asx, lx , ( ) ;
ny, Asy, ly ,
:
.
N< Rs As,
As - .