Crack control in FRC tunnel linings

The present paper deals with structural behavior of concrete linings at Serviceability Limit State (SLS) in order to evaluate the advantages resulting from the use of fiber reinforcement in addition to rebars with respect to the crack behavior and the durability. Experimental tests have been carried out on reinforced concrete prisms having different size, reinforcement ratio, concrete cover and fiber content. Particular attention was devoted to the influence of fibers in enhancing the post-cracking response in terms of reduction of displacements and crack spacing. An analytical model, validated by means of a comparison with the experimental data, is proposed to estimate the significant improvement of the crack control provided by Fiber Reinforced Concrete (FRC). The model was adapted to describe the longitudinal sectional behavior of concrete tunnel linings and provides useful information for evaluating the maximum bending moment achievable in the lining section, without exceeding a certain required crack opening, which is of main importance for the structural durability