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.
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
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.
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.
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