40% Reduction in Precast Concrete Tunnel Segment Cost



Spain’s new wastewater tunnel achieves 40% savings on tunnel segment costs with Barchip’s macro synthetic fiber concrete reinforcement.

Project Description

The Santoña – Laredo tunnel is a 1.5 km, 4.3 m diameter TBM driven tunnel currently under construction in northern Spain. The tunnel is part of a wider wastewater collection pipeline designed to protect significant ecological marshlands from urban sprawl. Stakeholders in the project include;

  • Contractor: JV Acciona Infraestructuras – Ascan Empresa Constructora y de Gestión
  • Designer: Ingemey Consultores
  • Owner: Confederación Hidrográfica del Norte

Design Details

The 1.5 km long segmentally lined tunnel is driven by a 4.30 m diameter TBM. The Mixshield machine used for construction has a maximum thrust of 16,725 kN. The universal rings have a 5 + 1 segmentation and a length of 1.20 m. Internal diameter of the lining is 3.50 m with a thickness of 250 mm.

BarChip48 structural synthetic fiber is the primary segment reinforcement. 16 kg/m3 of steel bar, as additional bursting reinforcement, is placed at the jacking face and the radial joints of the segments. The steam cured segments have a characteristic compressive strength of 45 MPa.


EPC Synthetic Fiber Reinforced Precast Concrete Tunnel Segments (7) Barchip's Synthetic Fiber Reinforced Precast Concrete Tunnel Segments (10)


Benefits achieved from Synthetic Fiber Design

Originally the segments were reinforced with 95 kg/m3 of rebar cages. Switching to BarChip fiber reinforcement system eliminated more than 80% of the steel reinforcement. The switch to Barchip’s synthetic fiber eliminated the rebar cage and its inherent labour and reduced production cycle times by nearly 50%.

Cost comparisons undertaken by the contractor showed that the change to Barchip’s synthetic fiber reinforcement system achieved a saving of 40% on the segmental lining cost.

More Information

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