ABSTRACT
The design of steel fiber reinforced concrete (FRC) precast segmental liners was recently developed for the 3RPORT Project following American Concrete Institute (ACI) requirements and European standards. Nine load cases were analyzed including final ground and water loads with up to 8 bar of external hydrostatic pressure, as well as fabrication, handling, and TBM thrust loads. The TBM thrust produces concentrated forces that cause bursting and spalling stresses. Simplified analysis methods cannot describe the development of spalling stresses between TBM jack pads and do not account for the ductility of the steel fibers. Consequently, reinforcement bars may be unnecessarily prescribed based on analyses using such methods. Advanced 3D numerical models were developed including the use of a constitutive law for FRC. This allowed evaluation of post-cracking behavior during TBM thrust, crack width progress and consequent stress redistribution. These results justified exclusive use of steel fiber reinforcement.
