Common context
Common project roles include floor beams, roof beams, girders, columns, transfer members, and parts of braced or moment frames.
AISC v16.0 · W shape
W18X40
W18X40 weighs 40 lb/ft, has a depth of 17.9 in, a cross-sectional area of 11.8 in², and an x-axis elastic section modulus Sx of 68.4 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
- 40 lb/ft
- Area
- 11.8 in²
- Depth
- 17.9 in
- Elastic Sx
- 68.4 in³
From designation to geometry
Reading the W18X40 record
The 18 in depth series in W18X40 is a designation. The tabulated depth d is 17.9 in and flange width bf is 6.02 in. The separately listed detailing depth ddet is 17.875 in.
The web thickness tw is 0.315 in and flange thickness tf is 0.525 in. Keep the exact designation with these dimensions: matching the depth series does not guarantee matching flanges, web geometry or connection fit.
Ix = 612 in⁴ and Iy = 19.1 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 W18X40
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 × 40 lb/ft | 800 lb | 362.874 kg |
| 3 pieces | 3 × 800 lb | 2,400 lb | 1,088.622 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 wide-flange shape?
A W-shape is a hot-rolled, doubly symmetric wide-flange section commonly used for beams and columns. Its relatively wide flanges and web distribute material efficiently for many bending and axial-force applications.
Learn how shape properties workDetailing watch
Confirm orientation, camber, flange and web connection access, unbraced length assumptions, copes, stiffeners, and the exact grade and availability required by the project.
Portable reference files
Download W18X40 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
Take a printable datasheet, spreadsheet, structured record, or plain-text table.
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
W18X40 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
- 40 lb/ft
- A Area
- 11.8 in²
- d Depth / angle leg dimension d
- 17.9 in
- ddet Detailing depth
- 17.875 in
- bf Flange width
- 6.02 in
- bfdet Detailing flange width
- 6 in
- tw Web thickness
- 0.315 in
- twdet Detailing web thickness
- 0.313 in
- tf Flange thickness
- 0.525 in
- tfdet Detailing flange thickness
- 0.5 in
- kdes Design k distance
- 0.927 in
- kdet Detailing k distance
- 1.188 in
- k1 Web-toe k distance
- 0.813 in
Centroid & detailing
- T Detailing T distance
- 15.5 in
- WGi Workable gage, inner
- 3.5 in
X-axis properties
- Ix X-axis moment of inertia
- 612 in⁴
- Zx X-axis plastic section modulus
- 78.4 in³
- Sx X-axis elastic section modulus
- 68.4 in³
- rx X-axis radius of gyration
- 7.21 in
- rts Effective radius of gyration
- 1.56 in
- ho Flange centroid distance
- 17.4 in
Y- and z-axis properties
- Iy Y-axis moment of inertia
- 19.1 in⁴
- Zy Y-axis plastic section modulus
- 10 in³
- Sy Y-axis elastic section modulus
- 6.35 in³
- ry Y-axis radius of gyration
- 1.27 in
Torsion, warping & perimeters
- J Torsional constant
- 0.81 in⁴
- Cw Warping constant
- 1,440 in⁶
- PA Shape perimeter PA
- 52.6 in
- PB Shape perimeter PB
- 58.6 in
- PC Shape perimeter PC
- 41.8 in
- PD Shape perimeter PD
- 47.8 in
Compare published reference values
W18X40 alongside nearby W records
These records share the same nominal series, outside envelope or leg arrangement, depending on the 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) |
|---|---|---|---|---|---|
| W18X40 (this record) | 40 | 17.9 | 11.8 | 612 | 19.1 |
| W18X35 | 35 | 17.7 | 10.3 | 510 | 15.3 |
| W18X46 | 46 | 18.1 | 13.5 | 712 | 22.5 |
Relative to W18X40, W18X35 changes nominal weight by -5 lb/ft, listed depth by -0.2 in, and area by -1.5 in². At the same hypothetical 20 ft length, the nominal weight difference is -100 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