W-Shape Section Properties Quick Reference — Top 50 W Shapes

Quick-reference table of section properties for the top 50 most commonly used AISC W-shapes. Properties listed include depth (d), flange width (bf), flange thickness (tf), web thickness (tw), cross-sectional area (A), moment of inertia about the strong axis (Ix), elastic section modulus (Sx), radius of gyration (rx), and plastic section modulus (Zx).

These properties are the foundation of all structural steel beam and column design. Every flexural capacity check, deflection calculation, and buckling analysis starts with these geometric values. For the complete database of 148 W-shapes, use the section properties tool.

Understanding Section Properties

PRELIMINARY — NOT FOR CONSTRUCTION. All results are for educational and reference use only. Must be independently verified by a licensed Professional Engineer (PE) or Structural Engineer (SE) before use in any project.

Top 50 W-Shapes — Section Properties Table

All values per AISC Steel Construction Manual, 16th Edition, Table 1-1. Shapes are grouped by nominal depth and sorted by increasing weight within each depth group.

W4 through W8

W10

W12

W14

W16 through W18

W21 through W30

Source: AISC Steel Construction Manual, 16th Edition, Table 1-1. All values in US customary units.

How to Use This Table for Beam Selection

Given a required moment (Mu) and span (L), the selection process is:

1. Calculate required Zx: Zreq = Mu / (0.90 * Fy). For Fy = 50 ksi: Zreq = Mu(kip-ft) * 12 / 45 = Mu * 0.267 in^3.
2. Scan the Zx column for the lightest shape exceeding Z_req.
3. Check deflection: If deflection limits control (common for longer spans), calculate required Ix = 5wL^4 / (384E _ delta_allowable). For typical floor beams with L/360 live load deflection limit: I_req = 5 _ w*ll * L^4 / (384 _ 29000 _ L/360) = 0.000194 _ w_ll * L^3.
4. Check bf/2tf ratio (flange local buckling) against lambda_pf = 0.38 * sqrt(E/Fy) = 9.15 for Fy = 50 ksi.
5. Verify h/tw ratio (web local buckling) against lambda_pw = 3.76 * sqrt(E/Fy) = 90.6 for Fy = 50 ksi.

For most W-shapes in the table above, both flange and web are compact (bf/2tf < 9.15 and h/tw < 90.6), so full plastic moment capacity can be used.

Column Selection Using rx

For column design, rx (strong-axis radius of gyration) and ry (weak-axis radius of gyration) control the buckling resistance. A column with KL = 15 ft (180 in) requires:

• For KL/rx = 50: rx_needed = 180/50 = 3.60 in (W8x31 through W14x48 meet this)
• For KL/ry = 50 (if braced equally in both axes): ry_needed = 3.60 in — only W8x31 (ry = 2.02), W10x49 (ry = 2.54), W14x90 (ry = 3.70) approach this

The weak axis (ry) typically controls column design. W14 sections with their wide flanges and balanced rx/ry ratio (rx/ry near 3.0) are the most efficient column sections. HSS square sections (rx = ry) are even more efficient, which is why they dominate column design in braced frames.

Frequently Asked Questions

What does Sx represent and when do I use it? Sx is the elastic section modulus (I/c), the ratio of moment of inertia to the distance from the neutral axis to the extreme fiber. It is used for elastic stress calculations: bending stress fb = M/Sx. In Allowable Strength Design (ASD), the allowable bending stress is Fb = 0.66Fy (for laterally braced compact sections), so allowable moment = Sx _ 0.66Fy. For A992 steel (Fy = 50 ksi): allowable moment = Sx _ 33 ksi.

How does Zx differ from Sx? Zx is the plastic section modulus, which accounts for the full plastification of the cross-section. When a beam reaches its plastic moment, the entire cross-section yields in tension or compression rather than just the extreme fibers. The shape factor Zx/Sx for W-shapes is approximately 1.12-1.18. In LRFD: phi*Mn = 0.90 * Zx _ Fy. The difference means a W12x26 (Sx = 33.4 in^3, Zx = 37.2 in^3) has 11% more moment capacity in LRFD than ASD.

What is rx and why does it matter? rx is the radius of gyration about the strong axis: rx = sqrt(Ix/A). It measures how efficiently the section's area is distributed relative to the x-x axis. A higher rx means greater buckling resistance. The slenderness ratio KL/rx determines whether a column buckles elastically or inelastically per AISC 360 Chapter E. For long columns, compressive strength Fcr decreases rapidly as KL/r increases.

Which W-shapes are best for floor beams? For typical office floor loading (50 psf live + 15 psf dead at 8-10 ft spacing), W18 through W24 shapes provide the best Ix-to-weight ratio. W21x44 through W24x68 are workhorse sections for 25-35 ft spans. For short spans (15-20 ft), W12 through W16 sections are more economical. For long-span girders (35-50 ft), W27 through W30 sections are needed.

How do I convert these properties to metric? Multiply inches by 25.4 for mm dimensions. Ix in in^4 _ 41.62 = cm^4. Sx and Zx in in^3 _ 16.39 = cm^3. rx in inches _ 25.4 = mm. Area in in^2 _ 645.16 = mm^2.

Where can I find the complete W-shape database? The AISC Steel Construction Manual contains all 148 W-shapes in Tables 1-1 through 1-12. Our free section properties tool provides instant access to all properties for all shapes online.

Try it now: Search any W-shape with our free section properties lookup tool

Related Pages

• Section Properties Database — Full searchable database of 500+ shapes
• W Beam Span Tables — W-shape spans for every loading condition
• Moment of Inertia Calculator — Calculate Ix, Iy from dimensions
• Steel Column Design Guide — Using rx, ry in buckling calculations
• Beam Capacity Calculator — Uses Sx, Zx in flexure checks

Disclaimer

This page is for educational and reference use only. It does not constitute professional engineering advice. All design values must be verified against the applicable standard and project specification before use. The site operator disclaims liability for any loss arising from this information.

Design Resources

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• Column Capacity Calculator
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• How to Read Steel Section Tables
• Steel Beam Design Guide