:
,
n , n = 1,2;
- ;
= 0,3 ( );
= 2,06∙104 /2.
1)
H=
2)
H=
3)
H=
3.3 12
1 2 :
t ;
ρ = 7850/3 .
1)
;
2)
;
3)
4. ( )
. . 4.1.
:
- , ;
, .
1)
2)
3)
:
,
γ = 1,2, γg = 1,05 ;
( ).
- .
1)
;
2)
;
3)
;
4.2 Mmax Qmax
( 6):
, = 6
.
1)
2)
3)
. 4.1
4.3
, ,
= 1,1 ;
Ry =240 = 24 /2 ;
γ = 1 .
1) ;
30 8239-89 ., I = 7080 4, W = 472 c3, = 46.5 2. , .. W=371 3 > W=269.32 3
,
,
.;
.
2) ;
33 8239-89 ., I =9840 4, W = 597 c3, = 53.8 2.
.
3) ;
36 8239-89 .,
I = 13380 4, W = 743 c3, = 61.92.
.
4.4 1 2 :
1)
2)
3)
4.6 1 2:
1)
2)
3)
.
4.7 ( + ) 1 2 :
- 1 .
4.3 /
, | 27772-88 | |||
235 | 245 | 255 | ||
2-20 | 16 000 | 18 000 | 20 000 | |
2-20 | 18 000 | 20 000 | 22 000 |
1)
.
2)
.
3)
.
4.4 - -
I | II | III | ||
/2 | ||||
/2 | ||||
- : | . . |
- I.
|
|
5. .
.
. -, 6 ( 5.1.1.).
5.1.1. .
- :
g = (g +g0)∙∙1,02,
g0 , 1 2 ;
1,02 ;
( ).
g = 1,02∙(26+0.95)∙6=164.9 /.
:
g = (g∙γ +g0∙γg)∙∙1,02,
g = (26∙1,2+0.95∙1.05)∙1,02∙6 =197/.
:
max = = = 4161.63 ∙ = 416163 ∙.
:
Qmax = = 1280.5 .
, 5.1.2.
5.1.2. .
.
.
W = = 18904 3.
, :
h = ,
tω = 7+3∙h , ;
k = 1,15;
;
.
tw = 12 .
h = 1,15∙ = 144.3 .
:
hmin = ,
hmin = = 63.3 .
.. h > hmin, h = 140. ,
:
tω = = 1 ,
, :
.
:
I = W∙h/2 = 18904∙140/2 = 1323280 c4.
, 2,1.
Iω = tω∙h3ω/12 = 1,1∙1353/12 = 205031.3 4.
, :
If = I Iω = 1323280-205031.3= 1118248.7 4.
:
f = ,
h0 = h-tf = 140-2,5 = 137.5 .
f = = 118.3 2.
f =bf×tf,
tf=2tω=2.5 .
480×25 .
:
, .
b t : , :
; (48-1,2)/2/2,5 0,5×29,9.
9.36 < 15.
. :
I = Iω + If = Iω + 2∙bf∙tf∙ ,
|
|
I = 205031.3 + 2∙48∙2.4∙ = 1339406.3 c4;
W = = = 19134.4 c3;
:
= = = 22,7 /2 < R=23/2.
1.3 %, 5%.
, .. .