Italian Concrete Days 2018
GFRP reinforcement for segmental linings of mechanized tunnels
The use of Glass Fibre Reinforced Polymer (GFRP) reinforcements is gradually spreading to replace or to integrate the traditional steel rebar for tunnels excavated with shielded TBMs and lined with precast segmental lining. The complete replace-ment of the steel rebars with GFRP ones is particularly used for segments that should be demolished after their installation, for ex-ample for cross-passages or niches realization. GFRP reinforcements cages placed on segments' edges can play an important role to limit the number of cracks and local breakages caused by impacts and unforeseen load conditions, mainly before and during the lin-ing installation. The analyses' results on a 3D model, which allowed to consider the contribution of such reinforcements both during the lining erection and the service, show that they can increase the lining strength. Moreover, GFRP rebars perimetric cages can be coupled with steel fiber reinforcement (SFRC) to increase the overall flexural and local resistance of segments. Examples of dimen-sioning and results of laboratory tests carried out to show the GFRP reinforcement effectiveness are reported.