Common context
Common project roles are project-specific and may include specialty beams, industrial framing, existing-condition matches, and members selected for unusual proportions.
AISC v16.0 · M shape
M5X18.9
M5X18.9 weighs 18.9 lb/ft, has a depth of 5 in, a cross-sectional area of 5.56 in², and an x-axis elastic section modulus Sx of 9.67 in³. Open the full US customary property record or generate 2D, data, report, and 3D reference files locally in your browser.
Nominal profile
Units · inches
Building nominal profile…
- Weight
- 18.9 lb/ft
- Area
- 5.56 in²
- Depth
- 5 in
- Elastic Sx
- 9.67 in³
From designation to geometry
Reading the M5X18.9 record
The 5 in depth series in M5X18.9 is a designation. The tabulated depth d is 5 in and flange width bf is 5 in. The separately listed detailing depth ddet is 5 in.
The web thickness tw is 0.316 in and flange thickness tf is 0.416 in. Keep the exact designation with these dimensions: matching the depth series does not guarantee matching flanges, web geometry or connection fit.
Ix = 24.2 in⁴ and Iy = 8.7 in⁴ refer to the database x- and y-axes. Here Ix is numerically larger. Axis letters are labels, not a guarantee that x is always the larger axis. These are geometric properties, not allowable loads or complete member capacities.
Match the axis and dimension conventions to the figures in the AISC v16.0 workbook Readme. The profile above simplifies manufacturing geometry; its outline is not used to recalculate the published properties.
Worked quantity example
Nominal weight for M5X18.9
Assume 3 pieces, each 20 ft (6.096 m) long. This is a hypothetical quantity example, not a stock-length or lifting recommendation.
| Quantity | Calculation | Nominal pounds | Kilogram equivalent |
|---|---|---|---|
| One 20 ft piece | 20 ft × 18.9 lb/ft | 378 lb | 171.458 kg |
| 3 pieces | 3 × 378 lb | 1,134 lb | 514.374 kg |
Conversion: 1 lb = 0.45359237 kg; displayed results are rounded. This multiplication excludes connection plates, bolts, weld metal, coatings, cutting allowances and actual material variation. Use the material takeoff for your own lengths and quantities.
Shape family context
What is a miscellaneous hot-rolled shape?
An M-shape is a miscellaneous doubly symmetric section that does not fit the standard W or S series proportions. The exact AISC record—not the nominal depth alone—defines its geometry and properties.
Learn how shape properties workDetailing watch
Verify exact designation, availability, flange geometry, gage, connection compatibility, and substitution criteria before detailing or procurement.
Portable reference files
Download M5X18.9 your way.
Every file is generated locally in your browser from the same nominal profile and AISC v16.0 reference record.
CAD, vector, and image
Use the profile in CAD, illustration, plotting, reports, or presentations.
Tables and portable data
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Extrude a nominal member
Enter a member length in inches. Mesh files are generated from the nominal reference profile.
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Dimensions & properties
M5X18.9 reference data.
Values below are derived from the AISC Shapes Database v16.0 in US customary units. A dash indicates that a property is not applicable or not included for this family.
Nominal dimensions
- W Nominal weight
- 18.9 lb/ft
- A Area
- 5.56 in²
- d Depth / angle leg dimension d
- 5 in
- ddet Detailing depth
- 5 in
- bf Flange width
- 5 in
- bfdet Detailing flange width
- 5 in
- tw Web thickness
- 0.316 in
- twdet Detailing web thickness
- 0.313 in
- tf Flange thickness
- 0.416 in
- tfdet Detailing flange thickness
- 0.438 in
- kdes Design k distance
- 0.813 in
- kdet Detailing k distance
- 0.813 in
- k1 Web-toe k distance
- 0.5 in
Centroid & detailing
- T Detailing T distance
- 3.375 in
- WGi Workable gage, inner
- 2.75 in
X-axis properties
- Ix X-axis moment of inertia
- 24.2 in⁴
- Zx X-axis plastic section modulus
- 11.1 in³
- Sx X-axis elastic section modulus
- 9.67 in³
- rx X-axis radius of gyration
- 2.08 in
- rts Effective radius of gyration
- 1.44 in
- ho Flange centroid distance
- 4.58 in
Y- and z-axis properties
- Iy Y-axis moment of inertia
- 8.7 in⁴
- Zy Y-axis plastic section modulus
- 5.33 in³
- Sy Y-axis elastic section modulus
- 3.48 in³
- ry Y-axis radius of gyration
- 1.25 in
Torsion, warping & perimeters
- J Torsional constant
- 0.313 in⁴
- Cw Warping constant
- 45.7 in⁶
- PA Shape perimeter PA
- 23.8 in
- PB Shape perimeter PB
- 28.8 in
- PC Shape perimeter PC
- 15 in
- PD Shape perimeter PD
- 20 in
Compare published reference values
M5X18.9 alongside nearby M records
No other record shares this exact nominal series; these are the nearest weights in the same family. Peers are ordered by absolute weight difference, then listed depth and designation. The table does not rank structural performance or approve a substitution.
| Record | Weight (lb/ft) | Depth (in) | Area (in²) | Ix (in⁴) | Iy (in⁴) |
|---|---|---|---|---|---|
| M5X18.9 (this record) | 18.9 | 5 | 5.56 | 24.2 | 8.7 |
| M12.5X12.4 | 12.4 | 12.5 | 3.63 | 89.3 | 2.01 |
| M12X11.8 | 11.8 | 12 | 3.47 | 72.2 | 1.09 |
Relative to M5X18.9, M12.5X12.4 changes nominal weight by -6.5 lb/ft, listed depth by +7.5 in, and area by -1.93 in². At the same hypothetical 20 ft length, the nominal weight difference is -130 lb.
Open these records in the full comparison tool
Compare the remaining dimensions, axis conventions, grade, availability and project requirements separately. Weight or section-property similarity does not establish matching connection geometry or member capacity.
Data is derived from the AISC Shapes Database v16.0, consistent with the AISC Steel Construction Manual, 16th Edition, 1st Printing. AISC advises professional verification before use in a specific application. The downloadable DXF is a nominal reference profile and may simplify rolled fillets, flange tapers, angle radii, HSS corner radii, and other manufacturing geometry. Verify all dimensions and suitability before design, detailing, ordering, or fabrication.
From reference to deliverable