. 9.
n = 1*8,2/4*7,9 = 0,25
. 1 max N max N
β = 2916.43/712.12 = 4.09
α1 = 7.9/8.2*√4/4.09 = 0.95, μ1 = 2, μ2 = 2,1
:
l = 2*8,2 = 16,4 l = 2,1*7,9 = 16,59
:
l = 8,2 l = 7,9-1,6+1,7 = 4,6
l= l/0.43h = 16,59/0,43*0,65 = 59,35
l = 2,06
ex = M/N = 637,82/712,12 = 0,89 ., mef = 3.1ex/h = 3,1*0,89/0,65 = 4,27 ϕ = 0,26
:
A = 712,12/0,26*24 = 109,55 2
500
= 110 2 ix = 31,3
Jx = 49750 4 iy = 7
Jy = 5400 4 h = 700
Wx = 1990 3 b = 400
Wy = 360 3 t = 18
. 10.
lx=16,59/0,313 = 53;
l=4,6/0,07 = 65,71;
mx=ex/Wx= 0.89*110/1990 = 3.93;
A/=1,4×32/(0,8×46)=1,2;
h /=0.94: h=1.46;
m1x=h×mx=1.46*3.93 = 5.73
l = 65,71 m1x= 5,73 j=0,26. s=712,12/0,26*110 = 24,9 /2 < R=25 /2.
. 11. M
< 24 /2
mx=M×A/(N×Wx) = 209,91*110/712,12*1990 = 0,016
c=b/(1+a×mx) = 1/1+0,7*0,016 = 0,98
ly=65,71 < (180-60α) = 160.2, jy=0,77
b a: b=1 1<mx<5; a=0,65+0,05×mx=0.33
( ) .
:
1:
, ex = M/N = 1610.64/1348.36 = 1,19
2:
, ex = 0,34
3:
, ex = 0,34
. ( ); , . t = 8 , h = 1255 .
. 12. :
) ; )
, (. 12,), , 2 *t (. 12, ). = 61,72
, , = 2*t* = 2*0,8*61,72 = 98,76 2
= = h/2 = 125.5/2 = 62.75 ,
|
|
= = /2 = 50,07 2
36
= 61,9 2 ix = 14,7
Jx = 13380 4 iy = 2,89
Jy = 516 4 h = 360
Wx = 743 3 b = 145
Wy = 71,1 3 t = 12,3
b t b/t <30.
, 450/16 = 28,12 <30, b = 450 , t = 16 .
= +b*tn +2*a*tc .
= 61,9+450*16+2*61,72*0,8 = 232,65 2
.
:
=
Jx = 268542.15 4
Jy = 6589.10 4
i = 28.17
iy = 4.8
= 61,9 + 0,8*125,5+1,6*45 = 234,3 2
Wx = 268542,15/36,6 = 7337,21 3
Wx = 268542,15/41,3 = 6520,23 3
λ = 227/28,17 = 8,05
λ = 113,5/4,8 = 23,64 < (180-60α) = 162
. . = +bn tn +hc tc. , , .
,
125,5/0,8 = 156,87 > 1.12
, .