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AISC Steel Shape Database: The Complete Reference Guide

SteelFlo Team7 min read

AISC Steel Shape Database: The Complete Reference Guide

Every structural steel estimator, detailer, and fabricator needs to be fluent in the AISC steel shape database. It's the definitive catalog of standard structural shapes rolled by domestic mills, and it governs everything from design to pricing to what you can actually order.

This guide breaks down the major shape families, their naming conventions, key properties, and what you need to know for estimating and fabrication.

What Is the AISC Shape Database?

The American Institute of Steel Construction (AISC) publishes and maintains a database of standard structural steel shapes. This database is the backbone of the Steel Construction Manual (currently the 16th Edition) and is available as a downloadable file from AISC's website.

The database contains dimensional and structural properties for every standard shape:

  • Cross-sectional dimensions (depth, flange width, web thickness, etc.)
  • Weight per linear foot
  • Cross-sectional area
  • Moment of inertia, section modulus, radius of gyration
  • Torsional properties
  • Compact/non-compact flange and web ratios

For estimating purposes, the two most critical properties are weight per foot (for material pricing) and dimensions (for connection design and clearance checks).

W-Shapes (Wide Flange)

W-shapes are the workhorses of structural steel. They're used for beams, columns, and sometimes bracing. If you had to pick one shape to know inside and out, this is it.

Naming Convention

W18x35 means:

  • W = Wide flange
  • 18 = Nominal depth (~18 inches, though actual depth varies slightly)
  • 35 = Weight in pounds per linear foot

Key Facts for Estimators

  • Range: From W4x13 (lightest) to W44x335 (among the heaviest standard rolled shapes)
  • Most common in building construction: W8 through W24 for beams; W10, W12, W14 for columns
  • Material grade: Almost universally A992 (Fy = 50 ksi) for new construction
  • Availability: Lighter W-shapes are typically stocked at service centers. Heavier and deeper sections (W36, W40, W44) may require mill orders with minimum tonnage requirements and 6–12 week lead times.

Common W-Shapes You'll See Repeatedly

| Shape | Weight (lb/ft) | Typical Use | |---|---|---| | W8x31 | 31 | Light columns, mezzanine beams | | W10x49 | 49 | Columns in low-rise buildings | | W12x26 | 26 | Filler beams, light framing | | W14x22 | 22 | Light beams, headers | | W16x31 | 31 | Floor beams, moderate spans | | W18x35 | 35 | Floor beams, office buildings | | W21x44 | 44 | Girders, longer spans | | W24x55 | 55 | Heavy girders, transfer beams |

Column W-Shapes

Engineers often select W10, W12, and W14 column sections because their flanges are nearly square, giving roughly equal strength in both axes. The W14 column family is the most extensive, ranging from W14x22 all the way to W14x730 — a single section that weighs 730 pounds per foot.

HSS (Hollow Structural Sections)

HSS members are used for columns, bracing, and exposed architectural steel. They come in three flavors: square, rectangular, and round.

Naming Convention

  • HSS8x8x1/2 = Square, 8" x 8" outside dimensions, 1/2" wall thickness
  • HSS10x6x3/8 = Rectangular, 10" x 6" outside dimensions, 3/8" wall
  • HSS8.625x0.500 = Round, 8.625" outside diameter, 0.500" wall

Key Facts for Estimators

  • Material grade: A500 Grade B (Fy = 46 ksi) or Grade C (Fy = 50 ksi). Always check the spec — Grade C is increasingly specified.
  • Availability: Common square and rectangular sizes are well-stocked. Unusual sizes or heavy walls may be harder to source.
  • Pricing: HSS typically costs more per pound than W-shapes due to the manufacturing process (forming and welding flat strip into a tube).
  • Connections: Welded connections to HSS can be more labor-intensive than W-shape connections. Access to the inside of the tube for through-bolting requires special details.
  • Sealing: Open ends must be sealed (cap plates or weld-closed) to prevent corrosion inside the tube, especially for exterior applications.

Channels (C and MC Shapes)

Channels have a C-shaped cross section with flanges on one side of the web.

Naming Convention

  • C12x20.7 = American Standard Channel, 12" deep, 20.7 lb/ft
  • MC12x10.6 = Miscellaneous Channel, 12" deep, 10.6 lb/ft

Key Facts for Estimators

  • Common uses: Stair stringers, light framing, struts, lintels, wall girts, channel caps on HSS columns
  • Material grade: A36 (Fy = 36 ksi) is standard for channels, though A572 Gr. 50 is sometimes specified
  • Pairing: Two channels back-to-back are sometimes used as columns or compression members, tied together with stitch plates

Angles (L-Shapes)

Angles are L-shaped members available in equal-leg and unequal-leg configurations.

Naming Convention

L4x3x3/8 means:

  • L = Angle
  • 4 = Long leg (inches)
  • 3 = Short leg (inches)
  • 3/8 = Thickness (inches)

Equal-leg example: L3x3x1/4

Key Facts for Estimators

  • Common uses: Bracing (single angle or double angle), lintels, shelf angles for masonry support, connections, miscellaneous framing
  • Material grade: A36 is standard; A572 Gr. 50 for higher-strength applications
  • Shelf angles: L-shapes supporting brick veneer are common in commercial construction. These are typically 5" or 6" leg, and lengths must match the facade layout exactly.
  • Pricing: Angles are among the cheapest structural shapes per pound

WT-Shapes (Structural Tees)

WT-shapes are made by cutting a W-shape in half along its web. The result is a T-shaped cross section.

Naming Convention

WT8x25 = Structural tee, 8" deep (cut from a W16x50), 25 lb/ft

Key Facts for Estimators

  • Common uses: Truss chords, bracing connections, hanger details
  • Not always stocked: Since they're cut from W-shapes, availability depends on the parent shape. Your service center may need to split them from stock W-shapes, adding a cutting charge.

Pipe

Standard, Extra Strong, and Double Extra Strong pipe sections are used for columns, bollards, and handrails.

Naming Convention

Pipe 6 Std = 6" nominal diameter, Standard wall Pipe 6 XS = 6" nominal diameter, Extra Strong wall

Key Facts for Estimators

  • Pipe and round HSS overlap significantly. Round HSS has largely replaced pipe in structural framing, but pipe still appears in older specs and for certain applications.
  • Material grade: A53 Gr. B for pipe; check if the spec distinguishes pipe from round HSS.

Plates

While not a "shape" in the rolled sense, steel plates are a massive part of every steel project.

  • Base plates — Under every column
  • Gusset plates — At brace connections
  • Stiffener plates — Inside beams and columns at connections
  • Shear plates — Single-plate connections (shear tabs)

Plates are specified by thickness and grade (typically A36 or A572 Gr. 50) and priced by weight. Plate pricing varies by thickness — very thin plates (<3/8") and very thick plates (>2") carry premiums.

Using the Shape Database for Estimating

When building a BOM or pricing a takeoff, the shape database gives you the weight per foot for every member. Your basic calculation:

Total weight = Quantity x Length (ft) x Weight per foot (lb/ft)

For example: 12 pieces of W18x35, each 28 feet long: 12 x 28 x 35 = 11,760 lbs (5.88 tons)

Tools like SteelFlo have the full AISC shape database built in, so when you identify a member as W18x35 during a takeoff, the weight calculation happens automatically.

Where to Get the Database

The AISC shape database is available for free at aisc.org/shapes. You can download it as an Excel file, and AISC also provides an online shape search tool. The database is updated periodically as mills add or discontinue shapes.

For your shop, keeping a current copy of the AISC Steel Construction Manual (16th Edition) on hand is still the gold standard. It includes not only the shape tables but also design aids, connection details, and specification commentary that inform estimating decisions daily.

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