The construction of underground infrastructures for both transport purposes (roads, railways, and metro) to face and solve the need of urban mobility but also for mountain, sea straits or rivers crossing and for water transportation (clean or sewage water) has today a relevant role in modern society. In this context, it assumes a particular importance the construction of tunnel linings in a shorter time and in safe conditions to remain within the project budget; full face mechanized tunnels are consequently under considerably improving all over the world with the adoption of bigger and more powerful machines; in this case, the linings are usually made of precast segments. Parallel to the improvement of mechanized methods of excavation, it is evident the need to also develop the behavior of these tunnel elements in terms of bearing capacity, crack control and water-tightness. To this aim, in the last two decades, Fiber Reinforced Concrete (FRC) was progressively adopted in several tunnel projects. The benefits related to the inclusion of fiber reinforcement in the cementitious composites are several but, the most important, is the noticeable increase of the post-cracking tensile residual properties. Moreover, the fiber reinforcement enables a considerable boost of the tunnel elements production process. The enhancement of the general structural behavior together with the improvement of the industrialization process of tunnel segments are probably the two main key-factors of the continuously growing use of FRC in precast tunnel linings. Within this framework, the aim of this report is to provide advances in the design of FRC tunnel lining in accordance with the objectives of the International Tunnelling Association (ITA) prescribed in Section II of the Statutes of the ITA (ITA, 1976). In fact, even if general standards or recommendations concerning the design of FRC elements are already available, the needed to shed some new light on the specific requirements and loading conditions of tunnel elements is considerable. This document was conceptually agreed during the meeting of ITA Working Group 2 in Budapest, 2009. The first early draft document was presented in Vancouver, 2010. After several discussions and meetings the current version was completed and presented herein.

Twenty years of FRC tunnel segments practice: lessons learnt and proposed design principles

TIBERTI, Giuseppe;PLIZZARI, Giovanni
2016-01-01

Abstract

The construction of underground infrastructures for both transport purposes (roads, railways, and metro) to face and solve the need of urban mobility but also for mountain, sea straits or rivers crossing and for water transportation (clean or sewage water) has today a relevant role in modern society. In this context, it assumes a particular importance the construction of tunnel linings in a shorter time and in safe conditions to remain within the project budget; full face mechanized tunnels are consequently under considerably improving all over the world with the adoption of bigger and more powerful machines; in this case, the linings are usually made of precast segments. Parallel to the improvement of mechanized methods of excavation, it is evident the need to also develop the behavior of these tunnel elements in terms of bearing capacity, crack control and water-tightness. To this aim, in the last two decades, Fiber Reinforced Concrete (FRC) was progressively adopted in several tunnel projects. The benefits related to the inclusion of fiber reinforcement in the cementitious composites are several but, the most important, is the noticeable increase of the post-cracking tensile residual properties. Moreover, the fiber reinforcement enables a considerable boost of the tunnel elements production process. The enhancement of the general structural behavior together with the improvement of the industrialization process of tunnel segments are probably the two main key-factors of the continuously growing use of FRC in precast tunnel linings. Within this framework, the aim of this report is to provide advances in the design of FRC tunnel lining in accordance with the objectives of the International Tunnelling Association (ITA) prescribed in Section II of the Statutes of the ITA (ITA, 1976). In fact, even if general standards or recommendations concerning the design of FRC elements are already available, the needed to shed some new light on the specific requirements and loading conditions of tunnel elements is considerable. This document was conceptually agreed during the meeting of ITA Working Group 2 in Budapest, 2009. The first early draft document was presented in Vancouver, 2010. After several discussions and meetings the current version was completed and presented herein.
2016
9782970101352
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Descrizione: ITA report n.16 - Twenty years of FRC tunnel segments practice: lessons learnt and proposed design principles
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11379/486251
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