ISO 657-11:1980

Overview

ISO 657-11:1980 is an International Organization for Standardization (ISO) standard that defines metric-series hot-rolled sloping flange channel sections (channel or U-sections). It specifies the designation, dimensions and sectional properties for sloping flange channel sections used in structural steelwork. Published as Part 11 of the ISO 657 series (first edition, 1980), the document includes a sample designation (for example CH 160 × 18) and a figure plus a tabulated dataset of geometric and mechanical section properties.

Key topics and requirements

• Designation format: Sections are designated by the letters CH followed by the depth and the mass per metre (e.g., CH 160 × 18).
• Dimensional data: Table entries provide key geometry parameters such as depth (H), flange width (B), web and flange thicknesses (T, t), and fillet/toe radii (R, r). The radii are given for information and for property calculations.
• Sectional properties: The standard tabulates engineering properties commonly required for design and analysis, including:
  • Mass per metre and cross-sectional area
  • Centroid location
  • Second moments of area (I) about principal axes (X–X and Y–Y)
  • Section modulus and radii of gyration
• Use for calculations: The dimensional and property data are intended for use in structural design, strength checks and stability analyses where standardized hot-rolled sloping flange channels are specified.

Practical applications

ISO 657-11 is used wherever standardized channel sections are required for reliable design data:

• Structural steel design of beams, purlins, bracing, frames and secondary members
• Steel fabrication and detailing for building, bridge and industrial structures
• Procurement and specification to ensure interchangeability and consistent supply of hot-rolled channel sections
• CAD libraries and structural analysis software that include catalogued section properties

Who uses this standard

• Structural, civil and mechanical engineers performing section sizing, load and stability checks
• Steel fabricators, roll-formers and manufacturers producing or supplying hot-rolled channels
• Detailers and BIM/CAD modelers creating accurate section libraries
• Procurement and quality assurance professionals specifying conformity to international section dimensions and properties

Related standards

• ISO 657 is a multi-part series covering hot-rolled steel sections; ISO 657-11 is one part addressing sloping flange channel sections. Designers should consult other parts of the ISO 657 series and national/industry standards for complementary section types or material specifications.

Keywords: ISO 657-11, hot-rolled steel sections, sloping flange channel, metric series, dimensions, sectional properties, CH designation, channel sections.