Question

strengths

Answer 1

A couple of things, note: all measurements are in kips, inches except M which is in kip-ft.
1. Area-moment of inertia, I
For parts 3 and 4, the depth should be (d-t)=4.3-0.32=3.98
2. I have x_bar=1.836
3. I have I=19.968, for some reason your I is way larger.
I use for each part
I=Area(height^2/12+(x_bar-cg)^2)
Also, for parts 1,2 and 5, I use the full width a & b, so that parts 3 and 4 have their cg at exactly d/2.
4. Moments equal -4.5 kip-ft=54 kip-in.
You have correctly calculated compression at the bottom flange because M=-4.5 kip-ft.
Some of my intermediate values:
Total area = 6.8864 in^2
\(\sum\)Area*x = 12.64064
x_bar = 1.83559
I=19.9676
Sb=I/x_bar=10.8780 (bottom)
St=I/(d-x_bar)=8.1024
M=-54 kip-in
I'll let you figure out \(\sigma_{top}\) and \(\sigma_{bottom}\).

Answer 2

I got it right.


max t = 2548psi = 2.54 ksi

max c = -1894 psi = -1.89 ksi

Answer 3

Excellent!