W-Shapes, HSS, Channels, Angles: Understanding Steel Member Types

If you're entering the structural steel industry — as an estimator, detailer, or shop worker — one of the first things you need to master is the vocabulary of steel shapes. Engineers and fabricators talk about W-shapes, HSS, channels, and angles the way carpenters talk about 2x4s and 2x12s. It's the basic language of the trade.

This guide covers every major structural steel member type you'll encounter, what they look like, where they're used, and what matters for estimating.

W-Shapes (Wide Flange Beams)

W-shapes are the most common structural steel member in building construction. They have an I-shaped cross section: two parallel flanges connected by a vertical web.

Profile

Imagine looking at the end of a steel beam. You see an "I" or "H" shape. The top and bottom horizontal pieces are the flanges. The vertical piece connecting them is the web. On W-shapes, the flanges are relatively wide compared to the depth — hence "wide flange."

Designation

W18x35 = Wide flange, 18" nominal depth, 35 pounds per linear foot

The actual depth may vary slightly from the nominal depth. A W18x35 is actually 17.7" deep, while a W18x97 is 18.6" deep — the heavier sections in a depth group have thicker webs and flanges, which adds to the actual depth.

Where They're Used

Beams — Spanning between columns to support floor and roof loads. The most common application.
Columns — W10, W12, and W14 column sections have nearly square profiles, providing similar strength in both directions. The W14 column family is the most extensive, from W14x22 to W14x730.
Transfer beams — Heavy W-shapes (W24, W30, W36) carrying concentrated loads from columns above.

Estimating Considerations

Grade: A992 (Fy = 50 ksi) is standard for all W-shapes in new construction
Availability: W8 through W24 in common weights are readily available from service centers. Heavier and deeper sections may require mill orders.
Cost per pound: W-shapes are generally the cheapest structural shape per pound — typically $0.55–$0.70/lb delivered from a service center.

HSS (Hollow Structural Sections)

HSS members are closed tubular shapes — square, rectangular, or round cross sections formed from flat steel plate or strip.

Profile

Think of a steel tube. Square HSS looks like a box. Rectangular HSS is a wider box. Round HSS is a pipe. All have uniform wall thickness around the perimeter.

Designation

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

Where They're Used

Columns — HSS columns are popular when the column is exposed (lobbies, atriums) because the clean profile looks better than a W-shape
Bracing — Square and round HSS are commonly used for diagonal bracing in braced frame buildings
Trusses — HSS chord and web members in architecturally exposed trusses
Canopies and exposed structures — The smooth surface finishes well for visible applications

Estimating Considerations

Grade: A500 Grade B (Fy = 46 ksi) or Grade C (Fy = 50 ksi). Check the spec — Grade C is increasingly standard.
Cost per pound: Higher than W-shapes, typically $0.70–$0.90/lb. The manufacturing process (roll forming and welding) adds cost.
Connections: HSS connections are generally more complex and expensive to fabricate than W-shape connections. You can't easily bolt to the inside of a tube, so connections rely more on welding, slotted gusset plates, or through-plates.
End sealing: Open ends of HSS must be sealed with cap plates to prevent interior corrosion.

Channels (C and MC Shapes)

Channels have a C-shaped cross section — a web with two flanges extending from the same side.

Profile

Looking at the end of a channel, you see a squared-off "C" shape. Unlike a W-shape where flanges extend equally from both sides of the web, channel flanges only go one direction.

Designation

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

The MC (miscellaneous) designation covers channels with non-standard proportions. In practice, C and MC sections are used interchangeably for many applications.

Where They're Used

Stair stringers — Channels are the most common stringer shape for steel stairs
Light framing — Girts (horizontal wall members), purlins (horizontal roof members), and small framing elements
Bracing connections — Channel caps over back-to-back angles or as strut members
Lintels — Over door and window openings, sometimes combined with angles
Edge framing — At floor openings, elevator shafts, and roof openings

Estimating Considerations

Grade: A36 (Fy = 36 ksi) is standard for channels
Cost per pound: Similar to angles, generally $0.55–$0.70/lb
Weight caveat: Channels are lighter than they look. A C12x20.7 weighs only 20.7 lb/ft — much lighter than a W12x26. Don't confuse channel weights with W-shape weights during takeoff.

Angles (L-Shapes)

Angles are L-shaped members with two legs meeting at a 90-degree corner.

Profile

Simple — two flat pieces meeting at a right angle. Equal-leg angles have the same dimension on both legs. Unequal-leg angles have one leg longer than the other.

Designation

L4x4x3/8 — Equal-leg angle, 4" x 4" legs, 3/8" thick
L6x4x1/2 — Unequal-leg angle, 6" long leg, 4" short leg, 1/2" thick

Where They're Used

Angles are the Swiss army knife of structural steel. You'll find them everywhere:

Bracing — Single angles or double angles (two angles back-to-back) are the most common bracing members in older and smaller structures
Lintels — Steel angles supporting brick or CMU over openings. A L5x3-1/2x5/16 is probably the most common lintel angle in commercial construction.
Shelf angles — Continuous angles supporting brick veneer at floor lines. These are critical and often heavy.
Connections — Clip angles, seat angles, and gusset stiffening angles
Miscellaneous framing — Supports, brackets, frames, and every other odd condition that needs a piece of steel

Estimating Considerations

Grade: A36 is standard. A572 Gr. 50 for higher-strength applications.
Cost per pound: Among the cheapest shapes, typically $0.50–$0.65/lb
Don't underestimate the tonnage. Angles seem small individually, but a building with 200 lintel angles, 50 bracing angles, and 300 connection angles adds up fast. This is the category most likely to be underestimated.

WT-Shapes (Structural Tees)

WT-shapes are made by splitting a W-shape in half along its web, resulting in a T-shaped cross section.

Designation

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

The naming convention tells you: a WT8 comes from a W16, a WT6 from a W12, and so on.

Where They're Used

Truss chords — The top and bottom members of steel trusses
Bracing connections — Gusset connections at the intersection of braces and beams
Hanger details — Supporting beams or equipment from above
Heavy connections — Where angles don't provide enough section

Estimating Considerations

Availability: WT-shapes are not always stocked. Service centers may need to split them from W-shapes, adding a cutting charge ($0.03–$0.08/lb).
Lead time: Factor in extra procurement time if your project uses non-standard WT sizes.

Plates

While not a rolled "shape," steel plate is present on every structural steel project.

Common Plate Applications

Base plates — Under every column, transferring load to the foundation
Gusset plates — At brace connections, distributing forces between members
Stiffener plates — Inside W-shapes at heavy connection points
Shear tab plates — Single-plate connections (the most common beam connection)
Cap plates — Sealing the tops of HSS columns

Estimating Considerations

Grade: A36 for most plates. A572 Gr. 50 for base plates and gusset plates in seismic applications.
Weight calculation: Steel plate weighs 40.8 lbs per square foot per inch of thickness (or 490 lbs per cubic foot).
Easy to miss: Plate material is scattered across detail sheets and connection standards, not concentrated on framing plans. Budget 5–15% of total structural weight for plate and connection material.

How This Applies to Estimating

Understanding member types matters for estimating because different shapes carry different costs:

Material cost varies by shape. HSS costs more per pound than W-shapes. Plates cost more per pound than both if purchased cut-to-size.
Labor varies dramatically. HSS connections take more hours than W-shape connections. Angle-intensive projects (lots of miscellaneous framing) have high piece counts and high handling time.
Availability affects schedule. Heavy W-shapes, unusual HSS sizes, and specialty grades may require mill orders with 8–14 week lead times.

When building a BOM, group your takeoff by shape type so you can apply appropriate pricing to each category. Tools like SteelFlo automatically categorize detected members by type and apply the correct unit weights from the AISC database, which eliminates a common source of error in the weight calculation step.

Quick Reference Card

| Shape | Common Grades | Cost/lb Range | Typical Use | |---|---|---|---| | W-Shape | A992 | $0.55–$0.70 | Beams, columns | | HSS (Square/Rect) | A500 Gr. B/C | $0.70–$0.90 | Columns, bracing, trusses | | HSS (Round) | A500 Gr. B/C | $0.75–$0.95 | Columns, bracing | | Channel (C/MC) | A36 | $0.55–$0.70 | Stairs, girts, framing | | Angle (L) | A36 | $0.50–$0.65 | Bracing, lintels, connections | | WT | A992 | $0.65–$0.85 | Trusses, connections | | Plate | A36 / A572-50 | $0.60–$0.90 | Base plates, gussets, connections |

These prices are approximate 2026 service center rates for common sizes and will vary by region, quantity, and market conditions.