The paper deals with the concrete lining behaviour at Serviceability Limit State (SLS) in order to evaluate the advantages that result from an optimized reinforcement based on the combination of rebars and fibers with respect to the crack behaviour of segmental lining. For Serviceability Limit State, an analytical model was developed to describe the tension stiffening of a concrete element reinforced with traditional rebars and fibers. A parametric study was carried out to better understand the behaviour of segmental lining with different tunnel depth projections. It is shown that fibers can substitute part of conventional reinforcement and, as additional benefit, significantly improve cracking behaviour of the segment.