Technical note: Optimum flexural design of steel members utilizing moment gradient and C b

Research output: Contribution to specialist publicationArticle


The application of C b to the design of members subjected to bending including beams as well as members subjected to combined loading, is discussed. The concept of C b and the formula for determining the modification factor is similar when using Allowable Strength Design (ASD) or the Load and Resistance Factor Design (LRFD) method. C b affects cases in which member relax length, L b is greater than L p and thus lateral-torsional buckling (LTB) controls flexural strength. Burgett and Tide offer a method for design of beams with C b >1.0 for the Allowable Stress Design (ASD) method. He recommends using an effective unbraced length instead of the original unbraced length. The amount of gain or benefit from C b varies, depending on section size, material properties, unbraced length, and value of C b.

Original languageEnglish (US)
Number of pages9
Specialist publicationEngineering Journal
StatePublished - Mar 1 2009


ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction

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