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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)
S15 x 50	15	5.64	486	15.7
S15 x 42.9	15	5.501	447	14.4
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

For the beam designations indicated below, determine the maximum normal stress $\sigma_x$ assuming that the maximum moment is equal to $M_{max} = 3 \times 10^5 \rm\ lb \cdot in$.

Designation	$\sigma_x$
S12 x 31.8
S12 x 50
S15 x 42.9
S10 x 25.4

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Correct answer

Designation	$\sigma_x$
S12 x 31.8	`8.25688073394`
S12 x 50	`5.90163934426`
S15 x 42.9	`5.03355704698`
S10 x 25.4	`12.0967741935`

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Question

QID:

demo/annotated/engBeamStress

Title:

Compute the normal stress

Variant

Started at:

2026-08-04 22:47:28 (CDT)

Duration:

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{
  "sigma1": 8.256880733944955,
  "sigma2": 5.901639344262295,
  "sigma3": 5.033557046979865,
  "sigma4": 12.096774193548388
}

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