Special design aspects in SFRC tunnel segments

This paper addresses design aspects of segmental tunnel linings made of steel fiber reinforced concrete (SFRC). An introduction to the de-sign of segmental linings with SFRC will be given. Particular design aspects will be addressed by referring to the new Line 9 of the Bar-celona Metro in Spain. Spalling cracks have been observed during the early phase of the construction. Research has been carried out to an-alyze the influence of irregularities on the load-bearing behavior of the segments. After the experimental determination of the material properties, non-linear analyses allowed to study the structural behavior of the tunnel segments under TBM thrust jack forces during the construction process. Following an introduction to the design particularities of SFRC segments, the attention is mainly focused on the ir-regularities that can occur in practice during the TBM operations and on the advantages coming from the use of SFRC in terms of crack control and load-bearing capacity of the tunnel segments.