Limitations of method for calculating slenderness using PD 6695-2:2008

Advisory Desk Note 545

Steel Construction Institute, 2025
Limitations of method for calculating slenderness using PD 6695-2:2008 Download document

Document Status

Current

Supplement

Civil & Structural Supplement

Series

Advisory Desk Note

Abstract

This SCI Advisory Note clarifies the limitations of using PD 6695-2:2008 Clause 5.2 for calculating the non-dimensional slenderness of steel beams, particularly in cases involving continuity over supports or end restraint. It explains that the method is intended for simply supported beams and may underestimate slenderness for more complex configurations, leading to overestimated buckling resistance. The note recommends using SCI P360 for improved accuracy, as it includes the influence of the bending moment diagram (C2 factor) and refined values for stability parameters. Alternatively, slenderness may be determined using finite element analysis to obtain the elastic critical moment (Mcr).

History

2025 edition.

Subjects

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

Publisher History

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

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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.

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