Prestressed CFRP for strengthening of reinforced concrete structures: Recent developments at Empa, Switzerland

Masoud Motavalli, Christoph Czaderski, Kerstin Pfyl-Lang

Research output: Contribution to journalArticleResearchpeer-review

77 Citations (Scopus)

Abstract

In civil engineering today, only 20 to 30% of the strength of carbon-fiber-reinforced polymer (CFRP) strips is used when they are applied as externally bonded strips for flexural and shear strengthening or in confinement of reinforced concrete (RC) structural elements. The strips are better used when the CFRP material is prestressed. This offers several advantages, including reduced crack widths, reduced deflections, reduced stress in the internal steel, and possibly increased fatigue resistance. In this paper, recent developments in the field of RC strengthening using prestressed CFRP are presented. The paper focuses on developments in flexural and shear strengthening and column confinement made at the Swiss Federal Laboratory for Materials Testing and Research (Empa). Several innovative ideas have been successfully realized in the laboratory. For example, a gradient prestressing technique without end anchorage plates was developed and successfully applied to a 17m RC bridge girder. A confinement technique using nonlaminated thermoplastic CFRP straps was also investigated and applied to 2m high RC columns. These results are encouraging, although practical and theoretical problems remain to be solved before these techniques can be fully applied.

Original languageEnglish
Pages (from-to)194-205
Number of pages12
JournalJournal of Composites for Construction
Volume15
Issue number2
DOIs
Publication statusPublished - Mar 2011
Externally publishedYes

Keywords

  • Confinement
  • Fiber reinforced polymer
  • Fiber-reinforced polymer
  • Flexural strength
  • Prestressing
  • Rehabilitation
  • Reinforced concrete
  • Shear strength
  • Switzerland

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