ר
. - 400×400.
, , , . , :
≤ 4,2 Ø 20* ,
= 4,8 Ø 20* ,
= 5,4 Ø 22,
= 6,0 Ø 25.
*-Ø .
1.
Ω = l × l = 5,6×6,0 = 33,62. 2. 4,8 γn = 1,0 :
- 1,0×[0,4×0,4×4,8+(0,3×0,7 +0,35×0,35) ×
×0,4] × 25=22,525
- - 1,1×22,525=24,7775 .
20, 500.
. 1 1 (. 13).
- , , 4 .
N = 338,69 + 3 ∙ 782,712+ 4 ∙ 24,7775 = 2785,94 .
:
(/2)× × | . , | , | ||
1. (, , ..) 2. ≈1,00/2 3. IV | 1,95×33,6×1,0 3,95×33,6×1,0 2,24×33,6 3,2×33,6×1,0 | 65,52 132,72 75,26 | 1,3 1,1 | 85,176 145,992 107,52 |
273,5 | 338,69 | |||
1. (1/2) 2. 3. . 2=0,9 | 3,95×33,6×1,0 2,5×33,6×1,0 0,9×15,0×33,6×1,0 | 132,72 453,6 | 1,1 1,1 1,2 | 145,992 92,4 544,32 |
670,32 | 782,712 |
2 -
|
|
- :
: .
. 2 2 (. 13).
, . max - N, .
(. 15). N , :
N = 338,69 + 3 ∙782,712 453,6 / 3 + 3 ∙ 24,7775 =2609,96
Nl =
. 1 .. k2 = 0,95 :
p = k2 ∙ γn ∙ pn ∙ lk = 0,95 ∙ 1,0 ∙ 1,2 ∙ 15 ∙6,0 =102,6 /.
:
-
: y0- (. );
- 2 = = 4,8 .
:
-
- :
:
= 320 ∙ 600 + 2 ∙ 160 ∙ 100 + 2 ½ 160 ∙ 100 = 240000 2.
:
S = 320 ∙ 600∙ 300 + 2 ∙ 160 ∙ 100 ∙ 150 + 2∙1/2 160 100 ∙ 2/3 ∙ 100 = =63466666,67 3.
:
( 14 ):
= 7083096196 4
2-2 :
-
-
1-1 ( ):
- :
- :
20 Rb =11,5 , Eb =
= 27500 .
500:
.
.
:
:
μ = 0,01
Ƹ:
:
:
= η∙ = 1,6∙37,54 = 60,1 ∙.
:
, .
:
As,tot = 3645,24 2,
As,tot =3265,28 2,
As,tot = AS+AS´=21641=3282 2 As,tot=2As,min=2bh0min=20,0015400350=420 2,
6Ø28 500 As = 36952 (+0,4%).
. 8 240 S = =300 .