Mechanics of failure in FRP strengthened reinforced concrete in shear

Monika Grusova, T J Ibell, A P Darby, M Evernden, J J Orr

Research output: Contribution to conferencePaperpeer-review


Carbon fibre reinforced polymer (CFRP) composite sheets and bars were used to strengthen reinforced concrete across a known plane to resist shear friction. The uncracked push-off specimens were either externally reinforced with CFRP sheets with a reinforcement ratio of 0.8% and 1.6% or internally with CFRP bars as additional shear reinforcement corresponding to 0.8% reinforcement ratio. Two ratios of internal steel reinforcement were considered representing the nominal stirrup reinforcement according to both historic (0.17%) and current design codes (0.26%). The effects of varying anchorage length of the CFRP on the shear friction capacity of the push-off specimens with externally bonded reinforcement (EBR) were studied through various strengthening schemes. Experimental results showed an increase in shear strength ranging from 23 – 84% compared to the unstrengthened control specimens. Tests with various wrapping schemes showed no evidence that additional shear friction capacity can be developed when beyond a sufficient anchorage length. However, specimens with short anchorage length failed prematurely due to the early debonding of the CFRP. The shear friction strength of the initially uncracked push- off specimens was determined using experimental results combining the shear friction contribution of the individual structural components, extending the currently accepted approach for internal steel reinforcement.
Original languageEnglish
Number of pages13
Publication statusPublished - Feb 2014
EventThe Fourth International fib Congress - Mumbai, India
Duration: 10 Feb 201414 Feb 2014


ConferenceThe Fourth International fib Congress


  • reinforced concrete
  • strengthening
  • FRP
  • shear
  • anchorage
  • deep embedment


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