Contrôle de la résistance de la conception
N ua ϕ steel N sa
=
N ua ϕ masonry N mbg
=
N ua ϕ bond N mag
=
250 lbs 0.75 8, 230 lbs = 4. 05 %
500 lbs 0.65 4, 737 lbs
= 16. 24 %
500 lbs 0.65 9, 106 lbs = 8. 45 %
Modes de défaillance par cisaillement
Défaillance de l’ acier- Résistance nominale
V sa = 0.60 A se, V f uta V sa =( 0.60)( 0.1419 in. 2)( 58, 000 psi) V sa = 4, 938 lbs
Rupture de la maçonnerie- Résistance nominale
V mbg = A Vm
A Vmo ψ ec, V, m ψ ed, V, m ψ m, V ψ h, V, m ψ parallel, V, m V b, m
A
Na = c Na + 8 in. + c Na c Na + 2. 187 in. A Na = 2 4.94 in. + 8 in. 4.94 in. + 2. 187 in. A Na = 127 in. 2
A Nao =( 2c Na) 2 A Nao =( 2( 4.94in.)) 2 A Nao = 98 in. 2 ψ ec, Na = 1.0( No Eccentricity Present)
ψ ed, Na = 0.7 + 0.3 c a, min c Na 2. 187 in. ψ ed, Na = 0.7 + 0.3
4.94 in. ψ ed, Na = 0.833
N ba, m = τ uncr, m πd a h ef N ba, m = 1, 074 psi π 0.5in.)( 5 in.) N ba, m = 8, 435 lbs
N mag = A Na A Nao
N mag = ψ ec, Na ψ ed, Na N ba, m
127 in. 2
1. 0 0. 833 8, 435 lbs 98 in. 2 N mag = 9, 106 lbs
A vm = 2 1.5c a1 + 1.5c a1 MIN h; 1.5c a1 A Vm = 2 6. 563 in. MIN 7.625 in.; 3. 281in. A Vm = 43 in. 2
2
A Vmo = 4.5 × c a1 AVmo = 4. 5 × 2. 187 in. 2 A Vmo = 22 in. 2
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