Constant life diagrams to prevent fatigue crack initiation in metallic beams using CFRP plates

Elyas Ghafoori, Masoud Motavalli, Alain Nussbaumer, Andrin Herwig, Gary S. Prinz, Mario Fontana, Xiao Ling Zhao

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

Abstract

The majority of fatigue strengthening studies using CFRP materials focus on reducing propagation rates of existing cracks or flaws, ignoring the crack initiation stage. However, many existing metallic bridge members do not contain existing cracks, but rather are nearing their design fatigue life wherein crack initiation is approaching. Limited research exists on the prevention of crack initiation using CFRP materials. In this paper, the use of CFRP plates with tuned degrees of pre-stress are investigated, to extend steel bridge member fatigue life (prevent crack initiation). The modified Goodman constant life diagram (CLD) is used to determine the safe regime of constant amplitude loading required to extend an existing member into the infinite fatigue-life zone. Following, the minimum level of CFRP pre-stress is determined to achieve this safe loading regime, and experimental testing of four metallic beams containing pre-stress CFRP retrofits validate the proposed method. Experimental results show that strengthening using pre-stressed CFRP plates can shift the working stresses from a finite fatigue-life zone to an infinite fatigue-life zone indefinitely preventing crack initiation.

Original languageEnglish
Title of host publicationProceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014
EditorsRaafat El-Hacha
PublisherInternational Institute for FRP in Construction (IIFC)
ISBN (Electronic)9781771363082
Publication statusPublished - 2014
Externally publishedYes
Event7th International Conference on FRP Composites in Civil Engineering, CICE 2014 - Vancouver, Canada
Duration: 20 Aug 201422 Aug 2014

Publication series

NameProceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014

Conference

Conference7th International Conference on FRP Composites in Civil Engineering, CICE 2014
Country/TerritoryCanada
CityVancouver
Period20/08/1422/08/14

ASJC Scopus subject areas

  • Polymers and Plastics
  • Civil and Structural Engineering

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