Title: Steel-fibre reinforcement for precast lining in tunnels with different diameters

Author(s): Alberto Meda; Zila Rinaldi

Publication: Symposium Paper

Volume: 310

Issue:

Appears on pages(s): 363-372

Keywords: Precast tunnel segment, segmental tunnel lining, fibre-reinforced concrete.

DOI:

Date: 3/17/2017

Abstract:
In the last few years, several research projects were realized at the University of Rome “Tor Vergata” on precast tunnel lining made with fibre-reinforced concrete without any other traditional reinforcement. The proposed technique exhibited several advantages with respect to the traditional reinforced concrete solution related not only to minor construction costs, but also (and more importantly) to high performance of the structure. The use of fibre reinforcement increases the impact strength of the segments, enhances the durability properties and reduces crack openings. Furthermore, it is possible to increase the quality of the production process in the precast plant and reduce the labour cost. The first experience was made in Panama with two hydraulic tunnels having a “small” diameter: “Monte Lirio Tunnel” and “Pando Tunnel” with an internal diameter of 3.2 m. A wide research effort on the definition of optimal fibre-reinforced concrete was developed during the design phase, with a series of full-scale tests. Eventually, the technology was applied on a hydraulic tunnel with a greater diameter: “El Alto Tunnel” with an internal diameter of 5.8 m. All these tunnels were designed according to the prescriptions of the fib Model Code for Concrete Structures 2010. This paper discusses some aspects related to the use of fibre-reinforced concrete in tunnels with different diameters and thicknesses.