You are viewing this question as it will appear in the manual grading interface. Return to the normal view when you are done.

Compute the normal stress

Consider the I-beam cross-section:

The table below has the geometric properties for different specifications for a steel beam:

Designation	h (in)	w (in)	Ix (in^4)	Iy (in^4)
S12 x 50	12	5.477	305	15.7
S12 x 40.8	12	5.252	272	13.6
S12 x 35	12	5.078	229	9.87
S12 x 31.8	12	5	218	9.36
S10 x 35	10	4.944	147	8.36
S10 x 25.4	10	4.661	124	6.79
S8 x 23	8	4.171	64.09	4.31
S8 x 18.4	8	4.001	57.6	3.73
S7 x 20	7	3.86	42.4	3.17
S7 x 15.3	7	3.662	36.7	2.64

For the beam designations indicated below, determine the maximum normal stress $\sigma_x$ assuming that the maximum moment is equal to $M_{max} = 2 \times 10^5 \rm\ lb \cdot in$.

Designation	$\sigma_x$
S8 x 18.4
S7 x 20
S12 x 35
S10 x 35

Note: this is an example of repeated variant question. Read more here.

Correct answer

Designation	$\sigma_x$
S8 x 18.4	`13.8888888889`
S7 x 20	`16.5094339623`
S12 x 35	`5.24017467249`
S10 x 35	`6.80272108844`

Student view placeholder

In student views this area is used for assessment and score info.

Tools

Staff information

Question

QID:

demo/annotated/engBeamStress

Title:

Compute the normal stress

Variant

Started at:

2026-08-05 00:41:35 (CDT)

Duration:

Show/Hide answer

{
  "sigma1": 13.88888888888889,
  "sigma2": 16.509433962264154,
  "sigma3": 5.240174672489083,
  "sigma4": 6.802721088435375
}

This box is not visible to students.