: .
( )
q (l 1 2 c 1)² = 8Rs(As1z1+ AsIzI); (1)
(2)
q 1 . ; , = 0,5hc, hc .
, 1
1
l1/l2 | As2/As1 | A sI/As1 AsI/As1 | AsII/As2 AsII/As2 |
1,2 1,4 1,6 1,8 2,0-3,0 | 1-1,2 1,2-1,4 1,3-1,6 1,5-1,8 1,8-2,2 2,0-4,0 | 1,0-2,0 | 1,0-2,0 |
hf = (1/30-1/25) lmax = (1/30-1/25)5200 ≈ 200.
g f | |||
/: r = 2500/³, hf = 200 | 1,1 | ||
/ : r = 2200/³, t = 20 | 1,3 | ||
: r = 1800/³, t = 15 | 1,1 | ||
: g = 6369 | |||
, υ | 1,2 | ||
.. (30%), υ l | 1,2 | ||
: υ = 7080 |
g n =0,95
q = (g + υ)gn = (6369+7080)0,95 = 12777 /²;
, h = 200 = 25:
h = h - =200-25=175;
h =400;
1=0,5 h = 0,5400 = 200;
- . l 1=4700;
, AsI = 1,5 As1 z I= z 1= 0,9 h (1):
1000 .
10Æ6 300; s=280 ²,
S=1000/10 = 100 .
6Æ10 300; sI =471 ², S= 1000/6 = 167
.. , 10 s = 170 .
1 :
2
- :
l 2=5200;
5Æ10 300; s=382 ², S=1000/5 = 200
10Æ8 300; s=500 ², S=100
%<5%
( (2) 1)
.
|
|
F = (g + υ) gn (l1 l2 h );
h = =400 ;
F =12777(47005200 - 400²)10-6 =310,2103;
:
Ab = um ho= 2300x175 = 201250 2
ho =200-25=175 ; :
um =4(h + ho)=4(400+175)=2300 ;
, Fb,ult = RbAb = 0,90,9201250 =163012 H;
.. F = 310,2 > Fb,ult = 163,0 , .
, :
Fsw,ult. =F - Fb,ult = 310,2 163,0 = 147,2 < Fb,ult
Æ6 240 (Rsw =170). h0 /3 sw = 56,6 ² s ≤ 0,25 h = 0,25400 = 100 .
, :
H
, : Fsw,ult = 0,8 qsw u = 0,896,221150 = 88522
Fsw,ult ≤ Fsw,ult. ≤ Fb,ult
.. Fsw,ult = 88522 > 0,25 Fb,ult = 0,25163012 = 40753 , .
.
:
Æ8 240(sw = 100,6 ²)
s = 60 < 0,25 h.