The W21x166 is a wide-flange structural steel shape listed in the W-shape reference data on this page. Use the dimensions and section properties below when reviewing a model, preparing connection details, or comparing the shape with other W sections.
This page identifies the governing reference as AISC 360-16, the AISC Specification for Structural Steel Buildings. The downloadable DWG file can support drafting and coordination, but the source geometry and project requirements should always be checked before it is used in design documentation.
W Beam
refer to : AISC 16
the American Institute of Steel Construction (AISC) Specification for Structural Steel Buildings (AISC 360-16), which is the 2016 edition of the AISC Specification for Structural Steel Buildings. It provides guidelines and requirements for the design, fabrication, and erection of steel structures in the United States.
Depth : 571.5 mm
Width : 315 mm
Web Thickness : 19 mm
Flange Thickness : 34.5 mm
Root Fillet Radius : 12.7 mm
Sectional Area : 314.84 cm2
Unit Weight : 247.1 kg/m
How to read the W21x166 reference data
The listed depth and width describe the principal envelope of the W shape. Web thickness describes the thickness of the central web, while flange thickness describes the thickness of the top and bottom flange material. The root fillet radius identifies the curved transition between the web and each flange; this detail can matter when checking clearances, cope geometry, and connection detailing.
Sectional area is a cross-sectional property used in member calculations and material quantity reviews. Unit weight expresses the mass of the shape per unit length and can assist with estimating member weight and handling requirements. These values should be used together with the applicable project specifications, material requirements, load effects, stability checks, and connection design.
Drafting and design workflow
For drafting, compare the DWG geometry with the dimensional reference before placing the section in a plan, elevation, or connection detail. For design work, do not treat the tabulated dimensions alone as a complete design check. Member selection, detailing, fabrication, and erection decisions require review of the complete project context and by a qualified engineer where applicable.
Related resources on this site may include the W-shapes reference, steel section properties, structural steel connections, and DWG drafting resources. These topics provide useful context when comparing this section or developing a coordinated steel detail.
W21x166 frequently asked questions
What type of section is W21x166?
W21x166 is a W-shape, also called a wide-flange structural steel section. The source data on this page provides its dimensional and mass properties.
What does the AISC 360-16 reference indicate?
The page identifies AISC 360-16 as the AISC Specification for Structural Steel Buildings. It provides a reference framework for the design, fabrication, and erection of steel structures in U.S. practice.
What is the root fillet on a W shape?
The root fillet is the curved transition where the web meets a flange. It is part of the rolled section geometry and should be considered when evaluating fit-up, clearances, and connection details.
Can the DWG file be used directly for fabrication?
The DWG is a drafting reference and should be reviewed against the project model, drawings, and applicable requirements before use. It should not replace fabrication documents, approved shop drawings, or engineering review.
Are the listed dimensions sufficient for member design?
No. The listed dimensions and properties are useful reference data, but member design also depends on loads, unbraced conditions, material requirements, limit states, connections, and project-specific engineering verification.
