Concrete tunnel linings can either be precast segmental linings, shotcrete or poured in place. In the past tunnel contractors have been faced with the arduous task of correctly pacing wire mesh or rebar reinforcement in tunnel linings. It is now common practice to reinforce the linings with fibers or a combination of fibers and rebar. Fibers have been in use for over 25 years as a reinforcing method in linings since they offer a more efficient and cost effective production as well as higher durability and fewer precast panel rejections. The performance characteristics of quality assured steel and macro fibers, now make it possible for tunnel linings to be manufactured entirely from fiber reinforced concrete.
Fiber reinforced tunnel segments can be designed through the use of ITA Technical Guidance notes for Precast Fibre Reinforced Concrete Segments or ACI 544.7R-16 Report on Design and Construction of Fiber-Reinforced Precast Concrete Tunnel Segments.