Crack control of tunnel linings using steel fibres

The present paper investigates the advantages of the use of steel fibre reinforced concrete for the realization of the lining of an Italian highway tunnel. Both serviceability and ultimate limit states have been considered. The benefits of the use of steel fibres are much more important when the serviceability limit states are concerned. In fact, the crack-bridging effect of the fibres reduces significantly the crack width for a given stress field. An optimization criterion for the lining thickness is proposed here, considering concretes with different amounts of steel fibres. The goal is also to assure a given value of the maximum crack width with a reduced thickness of the lining