Diseño óptimo de dovelas de hormigón reforzado con fibras para el revestimiento de túneles

The use of fibre reinforced concrete (FRC) in precast segments for tunnel support is an increasing practice. However, although the suitability of this material seems to be proven at a technical and economic level, there is still some reluctance towards the natural implementation of this material. In fact, in those cases in which fibres were added to concrete, the structural contribution was not taken into account in the design. This is mainly due to the lack of specific regulations to deal with this, as well as other aspects related to the control, production and design of FRC structures. Fortunately, at national level, Annex 14 of the Spanish EHE-08 already proposes guidelines as regards these aspects, and the new Model Code 2010 also considers the FRC as a structural material. This paper aims, on the one hand, to analyse the most important applications of FRC in tunnel linings worldwide and, on the other hand, presents a design methodology which enables the reinforcement configuration of fibre reinforced concrete in precast segments to be optimised. Furthermore, three real examples of application in which this method has been applied are described.