Advanced composites are being widely considered for use as reinforcement and prestressing tendons in concrete. However, many of the proposed applications consider them as direct replacements for existing steel products, which leads to nonsensical designs. This talk will consider the properties of the materials themselves, and in particular those aspects which differ from steel, to draw conclusions about the most logical ways in which they can be used. The elastic properties, the bond properties and the lack of ductility, imply that structures should be designed as over-reinforced, with partially bonded internal tendons, and resin-free external tendons. It will be shown that enhancement of the compression zone is possible by fibre-reinforcing or confining the concrete, and that requirements for shear need to be totally reworked in the absence of plasticity. The economic justification of advanced composites in concrete will be discussed, and commercial aspects will be covered.
Some novel forms of bridge structure will be presented, together with some successful applications.
