Mehdi Bakhshi - AECOM, New York, USA
Verya Nasri - AECOM, New York, USA

Precast concrete segments installed behind TBMs are designed as part of the one-pass lining system to resist the permanent, transient and construction loads. This paper discusses ultimate limit state (ULS) design of precast tunnel segments for all load cases including stripping, storage, transportation, handling, TBM thrust jack forces, grouting pressure, as well as final service stage loads including ground and groundwater loads and force transfer in segments joints. Best method of practice for ULS analysis and design are recommended. Required serviceability limit state (SLS) verifications for the design life of precast concrete segmental linings are discussed including stress, deformation and cracking of segments, as well as stress and deformation of joints. Particular attention is paid to flexural crack width calculation to compare with allowable crack width specified in various guidelines and standards. In addition, latest developments, technologies and innovations in segmental tunnel lining systems are presented including advanced ring configurations, ring connectors, sealing gaskets, and fiber reinforcement for segmental linings and shear recovery systems in penetration areas to tunnels

Crack width, design, fiber, lining, reinforcement, segment