. .
20: Rb=11,5, Rb,ser=15, Rbt=0,9, Rbt,ser =1,4, Eb=24*10 -3 ( ); -V: Rs,ser= 785, Rs=680,Es=1,9 *10-4 , -1: Rs=360, Es=1,7*10-4 .
(. . 1.2). . . :
h1=0,9×d=0,9×15,9=14,3;
h f=h`f=(h-h1)/2=(22-14,3)/2=3,85 ~3,9:
b=117-6×14,3=31,2 , b`f=117, .. h`f / h=3,9/22=0,177>0,1
.
, :
M ≤ Rb× γb2× b`f × h`f (h0 0.5h`f)
=37,8×10³<11,5×106× 0,9×1,17×0,039(0,19 0,5×0,039)=80,286 ×10³
h0= h =22 3 =19
, ,
b`f× h=11722.
, Rbp=0,5× 20=0, 5×30=15 . ().
σsp=0,6×Rsn=0,6×785=471 . n.1.23.[1]
σsp + ≤ Rs,ser; σsp - ≥ 0,3Rs,ser;
:
psp =30+360/l=30+360/5,65=93,7 ;
σsp + sp =471+93,7=564,7<Rsn=785 ;
σsp - sp=471 93,7=377,3 0,3×785=235,5
.. .
,
γsp = 1∆ γsp,
- ∆ γsp=0,5× sp / σsp(1+1/√np)=0,5×93,7/471(1+1/√4)=0,15
np- ; np=4- ( , ) .
γsp=1-0,15=0,85
σsp=0,85×471=400,35
:
0=M/ bf`×h²0×R b × γb2=37,8 ×103/1,17×0,192×11,5 ×106× 0,9=0,09
0=0,09 η=0,952 ξ=0,085
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(26)[1]:
ω=0,85-0,008 ×Rb× γb2 =0,85-0,008×11,5× 0,9=0,767
(25)[1]
ξR= ω/(1+ σsr /σsc,u (1- ω/1.1)=0,767/(1+679,7/500 (1-0,767/1,1)=0,54
σsr= Rs+400- σsp= 680+400-400,35=679,7
γs6, , (27)[1]
γs6= η-(η-1)(2 ξ/ ξR-1)≤ η
η=1,15 -V
γs6=1,15 (1,15-1) × (2×0,085 /0,54-1)=1,25 η=1,15,
γb6= η=1,15
:
sp=M/ η× h0 ×Rs ×γs6=37,8 ×103/680×106×0,19×1,15×0,952=2,7 ²
4 10 -V, Asp=3,140 2
.
Q=27,1. - .3.30[1], φw1=1 ( )
Q=27100 ≤ 0,3×φw1×φb1× Rb×γb2× b×h0,
- φb1=1-β Rb γb2=1-0,01× 11,5× 0,9=0,9
β , - 0,01
Q=27100<0,3× 1× 0,9× 11,5×106 × 0,9×0,312 × 0,19=165658
, .
--.
φ f, ( ), :
φ f=8× (0,75(3 h`f) h`f/b h0 )=7× (0,75× 3× 3,9× 3,9/31,2× 19)=0,40<0,5
φ n, , :
φ n=0,1N/ Rbt γb2 b h0,
N = sp× σsp=3,14×10-4× 400,35×106 =125710 =125,71
φ n=0,1N/ Rbt γb2 b h0=0,1×125710 /0,9×106×0,9×0,312×0,19=0,26<0,5
(1+ φ f +φ n)=1+0.40+0.26=1.66 ≥1.5
1.5
b= φb2(1+ φ f+φ n) Rbt × γb2× b× h²0=2× 1,5×0,9×106 ×0.9× 0,312× 0,19² =27,3. =27,3×10² .
φb2 2.
Qb= Qs=Q/2,
= b/0.5Qmax=27,3 ×10²/0,5 ×27,128= 201,5 2 h0×19=38, =2× h0=38.
Qb= b/=27,3×10²/38=71,8×10³. Q=27,1, , .
Ø5 -1. h≤450 ℓ1= ℓ0/4=600/4=150 5.27[1]:
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s≤ h/2=22/2=11 s≤11
s=10
, .
. , 0.7 . q ( kd=1.6), . 1.13 [1]
= ql21/2 = -0.5×4000×0.72 = -980 ×,
q = kdGc/l = 1.6×14125 /5,65= 4000 /;
Gc = [bf(hf+hf)+bphp] l = 2500[1.17(0.039+0.039)+0.312 ×0.142]5,65 =
14125 (Gc = 25340 H);
hp = h-(hf+hf) = 22-(3.8+3.8) = 14.4 ; b = 46,9 .
-1, 70 .
. :
N= qℓ/2=4000×5,65/2=11300 H.
As = N/Rs=11300/ 225× 106= 0.5 c2;
8 -1, s=0,503 2
:
1 2.03.01-84*