Design buckling resistance of angle sections

Advisory Desk Note 542

Steel Construction Institute, 2025
Design buckling resistance of angle sections Download document

Document Status

Current

Supplement

Civil & Structural Supplement

Series

Advisory Desk Note

Abstract

This SCI Advisory Note clarifies the distinction between flexural and torsional buckling resistances used for angle sections in the Blue Book. It explains that flexural buckling resistance (F) accounts for torsional-flexural effects and varies with member length, while torsional buckling resistance (T) does not, due to the absence of a warping term in angle sections. The note derives expressions for torsional resistance based on critical axial load, emphasising that warping is negligible for thin, intersecting rectangular elements. It references Eurocode guidance for effective slenderness in practical design, offering simplified methods for accounting for complex buckling interactions.

History

April 2025 edition.

Subjects

  • Steel building systems/frame
  • Building systems/frame
  • Building structure
  • Metal sections/other items
  • Steel
  • Materials

Publisher History

With over 30 years experience, the Steel Construction Institute provide technical expertise and best practice to the steel construction sector.

Information

NBS

NBS has produced specification systems and information products for construction industry professionals for more than 40 years. The National Building Specification is the recognised UK national standard and is used by over 5,000 organisations. NBS is part of RIBA Enterprises Ltd.

Accuris

We connect trusted knowledge to customers' workflows – mitigating risk, increasing efficiency and accelerating innovation For more than 60 years, leading R&D and engineering-intensive organizations have relied on us to achieve on-time, on-budget delivery of complex projects and new products. We deliver an unparalleled combination of technical content and Artificial Intelligence (AI) technologies to surface answers from the vast universe of technical knowledge, both inside and outside the organization. In a single interface, we connect the dots between information scattered across many different sources, allowing technical professionals to make better, more informed decisions faster.