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Structural steel shapes and sections: sizes, grades, and where to use them

A reviewer-grade reference for structural steel shapes, W, HSS, L, C, MC, WT, and PL, covering designation conventions, dimensional tables, ASTM grades, and the use cases that govern where each section belongs on a real project.

Structural steel shapes are standardized cross-sections manufactured by rolling or forming steel into specific profiles. Each shape is designated by a letter prefix (W, HSS, L, C, etc.) followed by dimensions that describe its geometry. Understanding these designations is essential for reading structural drawings, verifying member sizes, and coordinating steel framing with other building systems.

Reading Steel Designations

The designation tells you the shape type, nominal depth, and weight per foot (for rolled shapes) or dimensions and wall thickness (for HSS). For example, W12×26 is a wide flange that is nominally 12" deep and weighs 26 pounds per linear foot.

Steel Shape Types

W (Wide Flange)
W12×26
Beams, columns, girders, the most versatile and common structural shape
Designation Meaning
W = wide flange, 12 = nominal depth in inches, 26 = weight in lbs per linear foot
Profile
I-shaped with parallel flanges of equal width
Standard Grade
A992 (Fy = 50 ksi) standard for W shapes
HSS Rectangular
HSS8×4×3/8
Columns, braces, exposed framing, trusses, good for compression and bi-axial bending
Designation Meaning
HSS = hollow structural section, 8" × 4" outer dimensions, 3/8" wall thickness
Profile
Rectangular hollow tube with rounded corners
Standard Grade
A500 Grade C (Fy = 50 ksi) or A1085 (Fy = 50 ksi)
HSS Round (Pipe)
HSS6.625×0.280
Columns, handrail posts, truss members, exposed architectural steel
Designation Meaning
HSS = hollow structural section, 6.625" outer diameter, 0.280" wall thickness
Profile
Circular hollow tube
Standard Grade
A500 Grade C (Fy = 46 ksi) or A53 Grade B for pipe
L (Angle)
L4×3×3/8
Bracing, lintels, shelf angles, connections, stair stringers
Designation Meaning
L = angle, 4" long leg × 3" short leg × 3/8" thickness
Profile
L-shaped with two perpendicular legs
Standard Grade
A36 (Fy = 36 ksi) standard
C (Channel)
C12×20.7
Stair stringers, light framing, built-up sections, struts
Designation Meaning
C = channel, 12" depth, 20.7 lbs per foot
Profile
U-shaped with flanges on one side only
Standard Grade
A36 (Fy = 36 ksi) standard
MC (Miscellaneous Channel)
MC8×22.8
Similar to standard channels, available in additional sizes
Designation Meaning
MC = miscellaneous channel, 8" depth, 22.8 lbs per foot
Profile
Similar to C but different flange proportions
Standard Grade
A36 (Fy = 36 ksi) standard
WT (Structural Tee)
WT6×13
Truss chords, hanger connections, moment arm supports
Designation Meaning
WT = structural tee, 6" depth, 13 lbs per foot (cut from W12×26)
Profile
T-shaped, half of a wide flange cut along the web
Standard Grade
A992 (Fy = 50 ksi), same as parent W shape
PL (Plate)
PL 3/4×12
Base plates, stiffeners, gusset plates, connection elements
Designation Meaning
PL = plate, 3/4" thick × 12" wide
Profile
Flat rectangular section
Standard Grade
A36 (Fy = 36 ksi) or A572 Gr 50 (Fy = 50 ksi)

Common W Shape Sizes

Wide flange (W) shapes are the workhorse of steel construction. Beam sizes are selected for depth to minimize weight while meeting deflection limits. Column sizes use "square" sections (W14 column series) where flange width roughly equals depth.

Size
W8×10
Depth
7.89"
Weight
10 lb/ft
Flange
3.94" wide
Use
Light beams, purlins, girts
Size
W10×22
Depth
10.2"
Weight
22 lb/ft
Flange
5.75" wide
Use
Light floor beams, transfer beams in light structures
Size
W12×26
Depth
12.2"
Weight
26 lb/ft
Flange
6.49" wide
Use
Standard floor beams, infill beams
Size
W14×22
Depth
13.7"
Weight
22 lb/ft
Flange
5.00" wide
Use
Floor beams where depth is available
Size
W16×31
Depth
15.9"
Weight
31 lb/ft
Flange
5.53" wide
Use
Medium-span floor beams
Size
W18×35
Depth
17.7"
Weight
35 lb/ft
Flange
6.00" wide
Use
Long-span floor beams, girders
Size
W21×44
Depth
20.7"
Weight
44 lb/ft
Flange
6.50" wide
Use
Long-span girders, transfer beams
Size
W24×55
Depth
23.6"
Weight
55 lb/ft
Flange
7.01" wide
Use
Heavy girders, long-span beams
Size
W14×90
Depth
14.0"
Weight
90 lb/ft
Flange
14.5" wide
Use
Columns, equal depth and flange width
Size
W14×176
Depth
15.2"
Weight
176 lb/ft
Flange
15.7" wide
Use
Heavy columns in multi-story buildings

Steel Grades

Steel grade specifies the yield strength (Fy) and tensile strength (Fu) of the material. The grade must match the structural engineer's design assumptions.

Grade
A36
Fy (Yield)
36 ksi
Fu (Tensile)
58 ksi
Use
Plates, angles, channels, miscellaneous shapes
Grade
A572 Gr 50
Fy (Yield)
50 ksi
Fu (Tensile)
65 ksi
Use
High-strength plates, angles, channels where A36 is insufficient
Grade
A992
Fy (Yield)
50 ksi
Fu (Tensile)
65 ksi
Use
Wide flange shapes (W), the standard grade for structural beams and columns
Grade
A500 Gr C
Fy (Yield)
50 ksi (rect) / 46 ksi (round)
Fu (Tensile)
62 ksi
Use
HSS rectangular and round tubes
Grade
A1085
Fy (Yield)
50 ksi
Fu (Tensile)
65 ksi
Use
Premium HSS with tighter tolerances and enhanced properties
Grade
A514
Fy (Yield)
100 ksi
Fu (Tensile)
110 ksi
Use
High-strength quenched and tempered plate for specialized applications

Sources

AISC Steel Construction Manual, 16th Edition

AISC 360-22, Specification for Structural Steel Buildings

ASTM A6, Standard Specification for Rolled Structural Steel Shapes

Practitioner insight

“The fastest way to spot a templated structural review is whether the reviewer asked about the grade callout. W12×26 doesn’t tell you anything until you know whether the spec says A992 or A572 Gr 50 — the connection capacities and the shop drawing requirements are different. Every project we run AI plan review on, we flag missing grade callouts on the structural general notes sheet.”

— Source: Conversations with senior structural engineers and AISC-certified steel fabricator detailers on commercial and institutional projects, synthesized from Helonic’s structural review interviews, Q1–Q2 2026.

Structural Steel Shapes FAQ

What are structural steel shapes?
Structural steel shapes are standardized cross-sections rolled or fabricated from steel and used as the primary load-carrying elements in a steel-framed building. The most common shapes are W (wide flange), HSS (hollow structural section, rectangular and round), L (angle), C (channel), MC (miscellaneous channel), WT (structural tee), and PL (plate). Each shape is governed by AISC 360 and ASTM material specifications, and each has standard dimensions and weights published in the AISC Steel Construction Manual.
What does W12×26 mean in steel?
W12×26 is a wide flange (W) section that is nominally 12 inches deep and weighs 26 pounds per linear foot. The actual depth is usually slightly different from the nominal (W12×26 is 12.22” deep), so always verify against the AISC table when checking clearance against ductwork or sprinkler heads. W12 is one of the most common floor beam sizes in commercial construction.
What is the difference between W and HSS shapes?
W (wide flange) shapes are I-shaped solid rolled sections — strong in bending about the major axis and the standard for beams and columns where bending dominates. HSS (hollow structural sections) are tube-shaped — strong in compression and torsion and equally strong about both axes. HSS is the standard for bracing, exposed columns, and members where bi-axial bending matters. The grades are different too: W is typically ASTM A992 (Fy = 50 ksi); HSS is typically ASTM A500 Gr C or A1085.
What are the standard grades for structural steel?
ASTM A992 (Fy = 50 ksi) is the standard for W shapes and most rolled structural beams and columns. ASTM A36 (Fy = 36 ksi) is the standard for plates, angles, channels, and miscellaneous rolled shapes. ASTM A572 Gr 50 (Fy = 50 ksi) is used for higher-strength plate. ASTM A500 Gr C is the standard for HSS, with Fy = 50 ksi for rectangular and 46 ksi for round. ASTM A1085 is a premium HSS grade with tighter tolerances and uniform Fy = 50 ksi. Always confirm grade on the structural notes — substitutions are not free.
What is the difference between structural steel sections and structural steel shapes?
The terms are used interchangeably in industry. “Shape” is more common in the United States (AISC terminology); “section” is more common internationally and in academic structural engineering. Both refer to the same family of standardized cross-sections: W, HSS, L, C, MC, WT, S, M, HP, and PL. AISC publishes the dimensional and strength data for every shape in the Steel Construction Manual.
What are mild steel shapes?
“Mild steel” is an informal term for low-carbon structural steel — typically A36 plate, angles, and channels with Fy = 36 ksi. The term predates modern higher-strength rolled shapes. Today, most W shapes are A992 (Fy = 50 ksi), which is technically not “mild” steel. Use the ASTM designation on drawings, not “mild steel,” to avoid ambiguity with fabricators.
What are the types of structural steel members in a building?
By function: columns (vertical members carrying axial load to the foundation — typically W14 or HSS), beams and girders (horizontal members carrying floor and roof loads — typically W shapes), braces (diagonal members resisting lateral load — typically HSS or W in special concentrically braced frames), trusses (web members connecting top and bottom chords — WT, L, or HSS), and connection elements (gusset plates, base plates, angles — typically A36 plate). By cross-section: W, HSS, L, C, MC, WT, S, M, HP, and PL as covered in the AISC manual.
Where do I find a steel shapes chart?
The authoritative source is the AISC Steel Construction Manual, currently in its 16th edition (2023). It contains the complete dimensional table, design properties, and connection limits for every standard shape. For quick reference, AISC also publishes free shape databases (“v16.0 Shape Database”) as Excel files for use in structural design software. We summarize the most common W shapes and grades on this page; the full database covers hundreds of additional sections.
MG

Manas Gandhi

Co-founder & CTO, Helonic

Manas is the co-founder and CTO of Helonic, where he leads engineering and AI research for construction drawing analysis. He works directly with structural, MEP, civil, and fire protection engineers to translate the way they review drawings into AI systems that flag the issues that actually matter in the field. Before Helonic, he built machine learning pipelines for technical document understanding and has spent the last several years interviewing licensed design engineers and discipline leads to ground product decisions in real practice rather than industry assumptions.

Areas of focus
  • AI for technical document understanding
  • Cross-discipline coordination workflows
  • Code compliance automation (IBC, NEC, NFPA, IPC, IMC, ASCE)
  • Structural and MEP drawing review systems

How this page was researched: Shape designations, dimensions, and grade properties cross-checked against the AISC Steel Construction Manual (16th Edition), AISC 360-22 (Specification for Structural Steel Buildings), and ASTM A6 (Standard Specification for Rolled Structural Steel Shapes). Use-case mapping built from the structural framing plans of a sample of commercial drawing sets reviewed inside Helonic during Q4 2025\u2013Q2 2026.

Last reviewed by Manas Gandhi · May 2026

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