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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)
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
S6 x 17.25	6	3.565	26.3	2.31
S6 x 12.5	6	3.332	22.1	1.82
S5 x 14.75	5	3.284	15.2	1.67
S5 x 10	5	3.004	12.3	1.22
S4 x 9.5	4	2.796	6.79	0.903
S4 x 7.7	4	2.663	6.08	0.764

For the beam designations indicated below, determine the maximum normal stress $\sigma_x$ assuming that the maximum moment is equal to $M_{max} = 7 \times 10^5 \rm\ lb \cdot in$.

Designation	$\sigma_x$
S6 x 12.5
S7 x 15.3
S6 x 17.25
S4 x 7.7

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Correct answer

Designation	$\sigma_x$
S6 x 12.5	`95.0226244344`
S7 x 15.3	`66.757493188`
S6 x 17.25	`79.8479087452`
S4 x 7.7	`230.263157895`

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Question

QID:

demo/annotated/engBeamStress

Title:

Compute the normal stress

Variant

Started at:

2026-09-19 09:11:11 (CDT)

Duration:

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{
  "sigma1": 95.02262443438913,
  "sigma2": 66.7574931880109,
  "sigma3": 79.84790874524714,
  "sigma4": 230.26315789473685
}

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