A fully braced structural member in a building is subjected to several different loads, including roof loads of D = 5 k and L_r
= 7 k; floor loads of D = 6 k and occupancy L = 15 k; S = 18 k; and W = 17 k and E = 12 k (resulting from overturning forces on the lateral-force-resisting system). Consider the ASD load combinations described in Sec. 2.17 and assume the wind and seismic loads act in the same direction as the gravity toads. Find: The critical ASD combination of loads.
1 answer:
You might be interested in
Answer:
a)σ₁ = 265.2 MPa
b)σ₂ = -172.8 MPa
c)
d)Range = 438 MPa
Explanation:
Given that
Mean stress ,σm= 46.2 MPa
Stress amplitude ,σa= 219 MPa
Lets take
Maximum stress level = σ₁
Minimum stress level =σ₂
The mean stress given as
2 x 46.2 = σ₁ + σ₂
σ₁ + σ₂ = 92.4 MPa --------1
The amplitude stress given as
2 x 219 = σ₁ - σ₂
σ₁ - σ₂ = 438 MPa --------2
By adding the above equation
2 σ₁ = 530.4
σ₁ = 265.2 MPa
-σ₂ = 438 -265.2 MPa
σ₂ = -172.8 MPa
Stress ratio
Range = 265.2 MPa - ( -172.8 MPa)
Range = 438 MPa