Project Show Case

Lower Otta Hydropower Project of Norway announces ITA award winners

Since 2015,” the ITA Tunnelling and Underground Space Awards” international competition has honoured the most ground-breaking developments and outstanding initiatives in tunneling and underground space use. The event went digital after a difficult year, notably on health and safety issues, and awarded the best achievements across eight categories in the industry. Furthermore, ITA earned more than 52 submissions from 23 nations.

This virtual edition allowed more than 1,200 participants to gather, after editions in Switzerland, Singapore and France, China and the USA, revealing that the tunneling industry is still robust even through digital.

This Year’s project incl. Lower Otta Hydropower Project-Norway Renovation (up to € 50 M). The Nedre Otta Hydropower Project (Lower Otta HPP) is located on the Otta River, one of the Lågen River’s tributaries to the Glomma River, which is Norway’s longest river. The scope of the project phases consists of the construction of an intake system with a trash rack area of 200 m2 and two intake gates, 10.1 km unlined headrace and tailrace tunnel (90 m2), upstream and downstream surge tubes, 65,000 m3 powerhouse with concrete works of 15,000 m3.

The scheme includes 11 km of tunnels with a cross-section of up to 90 m2 (waterway) and a 65,000 m3 underground power plant with 2 Kaplan units (90 m3/s each). The project was divided into several building and supply contracts and managed with the assistance of Norconsult AS as the Owner’s Designer and Technical Advisor by the Management and Supervision Team from Hafslund-ECO.

The project was grounded on a phase of virtual design and construction (VDC) where a “digital twin” with feedback from all disciplines and suppliers was developed. The construction was carried out directly on the basis of the BIM without 2D drawing development. The underground operations (tunnels and caverns) have been carried out in a very successful way.

For the tunnelling works, Skanska used 2 Atlas Copco XE3 jumbos with 3 booms, drilling 5.2 m rounds to a 2/8 maximum cross section. For a 51-ton Cat 988, the packing was completed. The tunnel muck was transported by Cat 772 trucks with a gross weight of 51.6 tons. They had a capacity of 6 trucks in service at the field. There was one set of dump trucks in practice that supported all tunnel fronts. Notably, Average production rates of 55 m/week with production of up to 68 m/week for headrace and tailrace tunnels with a cross-section of 90 m2 were achieved (slightly better than planned) in a few weeks.

List of Winners

  • Project of the Year (between €50M and €500M) – Chinatown Station of the Central Subway Program – USA
  • Project of the Year incl. Renovation (up to €50M) – 2 Winners
  • Major Project of the Year (over €500M) – John Holland CPB Ghella Joint Venture Tunnelling and Station Excavation Works for the Sydney Metro City & Southwest Project – Australia
  • Technical Innovation of the Year – An Innovative Automated Geological Forward-prospecting Technique Mounted on Hard-rock TBM – China
  • Oddities of the Underground – Tunneling in the service of archeology – Israel
  • Innovative and Contributing Underground Spaces – Union Square Market Street Station – Battered Drilled Shafts as Permanent Ground Support – USA
  • Overcoming the challenges – Chengdu-Guiyang High-speed Railway—Yujingshan Mountain Tunnel Crossing Giant Karst Cave and Underground River – China
  • Young Tunneller of the Year – Josh Barry – Australia

–FEDRO’s Tunnel Renovation Method – renovation of a non-reinforced primary lining using night shifts while keeping all traffic lanes open during the day – Switzerland
– Lower Otta Hydropower Project – Norway

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