Tcxdvn 338 2005-ket cau thep-tieu chuan thiet ke
- 1. B¶ng 14 – C«ng thøc tÝnh ®é m¶nh t¬ng ®¬ng cña cÊu kiÖn rçng
§é m¶nh t¬ng ®¬ng λ o
Lo¹i
S¬ ®å tiÕt diÖn Víi b¶n gi»ng khi
tiÕt diÖn Víi thanh gi»ng
Ib l /(If b) < 5 Ib l /(If b) ≥ 5
1 y
A
x x λ0 = λ2 + 0,82λ2 (1 + n )
y 1 λ0 = λ2 + λ1
y
2
λ0 = λ2 + α1
y
1 Ad 1
(5.24) (5.27)
1 y (5.30)
b
1 y
2 2
α α
x x λ0 = λ2 + 0,82[λ1 (1 + n1 ) + λ2 (1 + n2 )]
2
2 λ0 = λ2 + λ1 + λ2
2
2 λ 0 = λ 2 + A 1 + 2
A
2
(5.25) (5.28)
d 1 Ad 2
1 y (5.31)
b
y
3 3
2A
x x λ0 = λ2 + 0,82[λ3 (1 +3n3 )]
2
λ0 = λ2 +1,3λ3
2 λ0 = λ2 + α1
3 3 Ad
(5.26) (5.29)
b (5.32)
y