Durability Concerns at the Oliola Water Tunnel
Barchip’s synthetic fiber concrete reinforcement eliminated the risk of corrosion in the sprayed concrete lining and cast in-situ lining, as well as the precast segments of the Oliola water tunel.
The Oliola water tunnel is part of the Segarra – Garrigues canal in North East Spain. This project was awarded to a Joint Venture of Acciona Infrastructures and M. y J. Gruas. The Euro 30.1 million contract comprises of a 4.8 diameter water tunnel approximately 7,000 metres in length.
Both the primary and the secondary linings and the precast segments use BarChip Shogun synthetic fiber in place of steel fiber and / or welded wire fabric. Approximately 30 tonnes of BarChip Shogun reinforcement was used over the entire project, dosed at 5 kg/m3.
Ground support consists of 5 x 2.0 metre rock bolts at 1 metre centres installed behind the cutting head and 50 mm of BarChip fiber reinforced shotcrete. A specially designed precast invert segment which forms part of the final lining is placed behind the TBM for the travelling backup and grouted into place.
The segment is reinforced with a steel cage and Barchip Shogun fiber to impart impact and abrasion resistance. Unlike the steel cage no concrete cover is required for the synthetic fiber so the full depth of the segment can be reinforced ensuring that any crack propagation is significantly reduced, critical in this type of construction where water may cause corrosion over the life of the asset.
The secondary lining is 300 mm in thickness and the form work consists of two 6 metre lengths capable of being moved and positioned individually. BarChip Shogun fiber was used to replace two layers of wire welded fabric. Replacing the steel reinforcement with BarChip Shogun reduced installation and cycle times and eliminated the high risk of corrosion.