The use of fiber reinforced concrete in tunnel linings, with or without conventional rebars, has increased in the two last decades, especially in segmental linings. The design process of segmental concrete linings in ground conditions generally refers to temporary loading conditions (demolding, storage, transportation, grouting process and TBM thrust jack phase) as well as to the final permanent embedded in ground condition. Within this framework, the present study investigates the possibility of using macro-synthetic fiber reinforcement in precast tunnel segments, which are part of a tunnel lining with an internal diameter of 3.5 m. Full-scale tunnel segments were tested under bending and high point loads representative of those exerted by the TBM during the excavation process. Different reinforcement solutions were considered: macro-synthetic fibers only (PFRC segments); combination of rebars and macro-synthetic fibers properly designed to obtain an optimized reinforcement solution (hybrid solution, RCO+PFRC segments) and the reference RC solution (traditional steel rebars only).
An experimental study on the behavior of precast tunnel segments reinforced by macro-synthetic fibers during temporary loading stages
Trabucchi Ivan;Mudadu Antonio;Tiberti Giuseppe
;Conforti Antonio;Plizzari Giovanni;
2020-01-01
Abstract
The use of fiber reinforced concrete in tunnel linings, with or without conventional rebars, has increased in the two last decades, especially in segmental linings. The design process of segmental concrete linings in ground conditions generally refers to temporary loading conditions (demolding, storage, transportation, grouting process and TBM thrust jack phase) as well as to the final permanent embedded in ground condition. Within this framework, the present study investigates the possibility of using macro-synthetic fiber reinforcement in precast tunnel segments, which are part of a tunnel lining with an internal diameter of 3.5 m. Full-scale tunnel segments were tested under bending and high point loads representative of those exerted by the TBM during the excavation process. Different reinforcement solutions were considered: macro-synthetic fibers only (PFRC segments); combination of rebars and macro-synthetic fibers properly designed to obtain an optimized reinforcement solution (hybrid solution, RCO+PFRC segments) and the reference RC solution (traditional steel rebars only).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
