The Hybox 355 SHS 400x400x12.5 is a square hollow structural section (SHS) reference for steel design, detailing, and CAD work. This page brings together the section dimensions, corner radii, sectional area, unit weight, and the applicable EN 10219-2 reference identified in the source data.
Use the values below when checking a preliminary layout, comparing hollow-section options, or preparing a fabrication drawing. Final member selection and connection design should be verified against the governing project requirements and by a qualified engineer.
Hybox 355 SHS 400x400x12.5
Hybox 355 Square Hollow Sections
refer to : EN 10219-2:2006-04
the European standard that specifies tolerances, dimensions, and sectional properties for cold-formed welded structural hollow sections made of non-alloy and fine grain steels. It complements EN 10219-1, which covers technical delivery conditions.
Dimension : 400x400x12.5
Depth : 400 mm
Width : 400 mm
Thickness : 12.5 mm
Outer Corner Radius : 37.5 mm
Inner Corner Radius : 25 mm
Sectional Area : 187 cm2
Unit Weight : 146.8 kg/m
Understanding the Hybox 355 SHS reference
SHS means square hollow section. Unlike an open steel profile, an SHS has four closed walls, which gives it a consistent square outside form and makes the section useful for columns, bracing, frames, posts, and fabricated assemblies where appearance and torsional behavior are important design considerations.
The designation 400x400x12.5 identifies the nominal outside depth, outside width, and wall thickness shown in the source data. The listed outer and inner corner radii are important for accurate detailing because the corners are rounded rather than perfectly sharp. They should be considered when sections meet plates, stiffeners, end connections, or other hollow sections.
How to use the listed section properties
The sectional area is useful for material takeoff, axial-resistance calculations, and comparison with other profiles. The listed unit weight supports preliminary mass estimates, handling planning, and shipping calculations. These values are reference properties for this section and should not be treated as a substitute for a complete resistance, stability, fatigue, fire, or connection check.
The source identifies EN 10219-2:2006-04 for dimensional tolerances, dimensions, and sectional properties of cold-formed welded structural hollow sections. It also notes the relationship with EN 10219-1, which addresses technical delivery conditions. Refer to the project specification and the applicable standard requirements when confirming material documentation, tolerances, inspection, and fabrication details.
CAD and detailing workflow
The downloadable DWG file can help users begin a two-dimensional drafting workflow for the profile. Confirm the drawing units, layer conventions, corner geometry, and project-specific tolerances before incorporating the file into production documentation. For related reference work, link this page with the site’s resources on square hollow sections, rectangular hollow sections, steel section properties, hollow-section connections, and DWG downloads.
Frequently asked questions
What does SHS mean?
SHS means square hollow section. It describes a closed steel profile with a square outside form and hollow interior.
What does 400x400x12.5 describe?
In this reference, the designation identifies the listed outside depth, outside width, and wall thickness of the section.
Why are corner radii listed?
Corner radii describe the rounded transitions between the flat walls. They matter when checking clearances, fitting plates or stiffeners, and representing the section accurately in drawings.
What is the sectional area used for?
Sectional area is commonly used in material quantity estimates and in engineering checks involving the steel area. It is only one of the properties needed for a complete member design.
What does the unit weight represent?
The unit weight indicates the listed mass per unit length of the section. It can support preliminary estimating, handling, and logistics calculations.
Is the DWG file ready for fabrication?
The DWG is a drafting reference for this section. Review its units, geometry, tolerances, and project requirements before using it in fabrication or issued construction documents.
