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Title: Bond behaviour of FRP bars in concrete
Author: Achillides, Zenon
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 1998
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This thesis investigates the bond behaviour of Fibre Reinforced Polymer (FRP) reinforcing bars in concrete elements both analytically and experimentally. Two series of experiments were conducted. In the first series, more than 100 cube specimens were tested in direct pullout. The mode of bond failure of FRP bars in the pullout tests was found in most cases to differ substantially from that of deformed steel bars. Within this series the parameters that influence bond development were examined. The bond strengths developed by CFRP and GFRP bars appear to be very similar, and just below what is expected from deformed steel bars. In the second series of experiments, nine beams were tested in four-point bending to examine the bond splitting behaviour of FRP single anchorages and splices. CFRP bars develop higher bond splitting strength than respective GFRP bars, which contradicts the findings of pullout tests. The lower elastic modulus of GFRP bars is thought to play an important role to their lower bond splitting strength. For this reason, the suitability of the cube tests for measuring the bond strength ofFRP bars for practical purposes is questioned. Spliced bars appear to develop similar bond splitting strength to single bar anchorages. The distribution of bond stresses along the anchorage length and the effect of flexural cracks on the bond development were also examined. The thesis also discuss other parameters that influence bond splitting such as transverse reinforcement, concrete cover, and support action. An analytical study was conducted to enhance further the understanding of the bond behaviour of FRP bars. Both the pullout and beam tests were modelled by using FE packages. Non-linear springs describing the bond behaviour of short embedment lengths were chosen and used for predicting the behaviour of longer embedments. The influence of flexural cracking was also considered in the case of beams. The analytical results showed a good correlation with the respective experimental. Finally, some important issues regarding the design of anchorage lengths for FRP reinforcing bars were addressed and a method of working towards the formulation of design recommendations is suggested.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available