Steel Member Design — Axial, Flexure & Shear

Axial compression, flexural and shear capacity for a W-shape, box (rectangular HSS) or round HSS member, checked against a demand you enter directly or derive from a load case and support condition.

AISC 360-16

Shape

Section typeDepthdinFlange widthb_finFlange thicknesst_finWeb thicknesst_win

Material & method

Yield strengthF_yksiModulusEksiMethod

Length & bracing

Member lengthLftKxKy

Demand

Axial PuP_ukipMoment / shear sourceMuxk-ftMuyk-ftVukip

Everything you have entered is in the address bar, so the link reproduces this exact calculation.

Available axial strength

513.7 kip

Available flexural strength (major)

532.7 kip·ft

Available shear strength

127.5 kip

Design checks

Check	Demand	Capacity	DCR	Status
Axial: φPn vs Pu	280.000 kip	513.704 kip	0.545	✓ OK
Flexure (major axis): φMnx vs Mux	45.000 kip·ft	532.734 kip·ft	0.084	✓ OK
Flexure (minor axis): φMny vs Muy	15.000 kip·ft	120.879 kip·ft	0.124	✓ OK
Shear: φVn vs Vu	20.000 kip	127.500 kip	0.157	✓ OK

Calculation

1Governing slenderness and elastic buckling stressAISC 360-16, document reference
$\frac{KL}{r} = \max\left(\frac{K_xL}{r_x}, \frac{K_yL}{r_y}\right), \quad F_e = \frac{\pi^2E}{(KL/r)^2}$
$KL/r = 86.600, \quad F_e = 38.18$
$KL/r$ 86.6
2Critical stress and nominal axial strengthAISC 360-16, document reference
$F_{cr} = \begin{cases}0.658^{F_y/F_e}F_y & KL/r \le 4.71\sqrt{E/F_y}\\0.877F_e & \text{otherwise}\end{cases}, \quad P_n = F_{cr}A_g$
$F_{cr} = 28.90, \quad P_n = 570.8$
$P_n$ 570.8 kip
3Nominal flexural strength (full plastic moment)AISC 360-16, document reference
$M_{nx} = F_yZ_x, \quad M_{ny} = F_yZ_y$
$M_{nx} = 591.9, \quad M_{ny} = 134.3$
$M_{nx}$ 591.9 kip·ft
4Nominal shear strengthAISC 360-16, document reference
$V_n = 0.6F_yA_w$
$A_w = 4.25, \quad V_n = 127.5$
$V_n$ 127.5 kip

Assumptions

Concentric axial load, uniaxial or biaxial bending with no torsion, non-slender flanges/webs/walls.
The unbraced length for the W-shape's flexural strength is short enough that lateral-torsional buckling does not govern — Mn is the full plastic moment.
Shear resistance and safety factors are applied uniformly across all three shapes (φv = 1.0, Ωv = 1.5, matching the compact-web I-shape value) pending shape-by-shape confirmation.

What this calculator does not check

Does not check local (slender-element) buckling of any flange, web or wall — every capacity here assumes a non-slender section. Check b/t, h/tw or D/t against the code's own limits separately.
Does not reduce the W-shape's flexural strength for lateral-torsional buckling. Valid only while the unbraced length is short relative to the section depth.
Does not combine axial, flexural and shear demand into a single interaction ratio (AISC Chapter H) — each is checked against its own capacity independently.
Every clause number this calculator would cite is unconfirmed against the published AISC 360-16 text — see docs/OPEN-QUESTIONS.md. Treat every capacity as indicative.
Round HSS shear capacity uses the same general Vn = 0.6 Fy Aw form as the other two shapes, with Aw taken as half the gross area — a common approximation, not the code's own (differently structured) round-HSS shear provision.

Results are for preliminary sizing and educational use. They are not a design and must be reviewed, verified and sealed by a licensed or registered engineer before being used in construction.

steel-member-design v1.0.0 · AISC 360-16 · input 4774ec0b82b83031