Characterization of Residual Stresses in Modern Welded Girders

• Author / Creator

  Unsworth, Daniel

• Residual stresses can have a significant impact on the stability of structural members. In the case of I-section beam elements, such stresses can impact lateral--torsional buckling (LTB) capacity, particularly in the inelastic range. I-sections are typically fabricated by either rolling as a single shape or welding three plates together; residual stress distributions can differ considerably between the two section types. It is therefore possible for a built-up welded girder to have a lower LTB capacity than that of a rolled one of identical cross-section. Concerns have been raised that such a difference may render Canadian steel design standards unconservative for welded girders. Because of the lack of recent physical LTB tests on welded girders, finite element modelling has been done to attempt to assess the design standard. Assumed residual stress distributions were based on data from 1970 to 1980 that may not be representative of modern fabrication processes. A paucity of residual stress data for current welded girders, however, prevents assessment of these assumed distributions. In this study, residual stress measurements are carried out on a series of four reduced-scale welded steel test girders. Testing consists of destructive sectioning tests and non-destructive ultrasonic measurements. A predictive residual stress model for modern welded girders is proposed, and the feasibility of the ultrasonic method for residual stress measurements addressed.

• Subjects / Keywords

  • Ultrasonic
  • Welding
  • Residual Stress
  • Non-destructive Testing
  • Steel

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-s130-jt41

• License

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