C. J. Burgoyne and J. M. Lees
Department of Engineering, University of Cambridge,
Cambridge, UK
The focus of the present study is
aramid fibre reinforced plastics (AFRPs) in pretensioned concrete applications.
Many of the problems that arise are due to the bittle nature of the tendons.
Complete bond leads to failure by the snapping of the tendon which is
catastrophic and occurs without warning. Unbonded tendons, on the other hand,
can slide relative to the concrete, which allow considerable rotation of
concrete elements at hinge positions when the structure is overloaded
Clearly, some bond is essential,
since the advantages of pretensioning are lost if anchorages are required.
Thus, the project is designed to determine the amount of bond and its optimum
distribution, to allow the concrete/aramid fibre reinforced plastic (AFRP)
composite to achieve its optimum performance.
The work is being carried out in
two phases. The first, experimental, phase investigates flexural tension on
small scales samples made in the laboratory. A second, developmental, phase
will be carried out in conjunction with Costain Dow Mac. During the second
phase, full scale (7-8m) prototype bridge beams using only fibre reinforced
plastic (FRP) reinforcement will be manufactured and tested. The design of
these beams will be based on the results of the experimental phase and will act
to consolidate our knowledge of the structural behaviour of fibre reinforced
plastic (FRP) reinforcement.
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