PROJECT DATA

NOvA detector plant cast in concrete into the rock, Minnesota

Project:  Detector plant cast in concrete into the rock below grade - 106 m long, 21 m wide and 21 m high

Contractor: Adolfson & Peterson Construction

MEVA Systems: MEVA wall formwork Imperial, climbing brackets KLK, support frame STB, heavy-duty braces Triplex

Formwork Engineering: MEVA Formwork Systems, Springfield, Ohio

 
 
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Project

Research on Origin of Matter sends Neutrino Beam travelling underground from Illinois to Minnesota

130 research scientists from more than 30 institutions will conduct first-time ever experiments to investigate the origin of matter by sending a beam of particles called neutrinos 810 km underground from their laboratory in Illinois to the woods of Minnesota, close to the Canadian border. The beam, travelling at close to the speed of light, will end in the so called NOvA Far Detector plant in which the properties of the particles will be examined in a huge tank of scintillator oil. The project entitled NOvA (short for NuMI Off-Axis ve Appearance) is being funded by the U.S. Department of Energy. The scientists hope to shed light on the question of antimatter, which some believe to be tied to the properties of neutrinos. 

Detector plant cast in concrete into the rock below grade
For scientific reasons, the NOvA Far Detector plant is secluded and its enclosure embedded 12 m in rock below grade. The 3,800 m² detector enclosure is 106 m long, 21 m wide and 21 m high. It will have cast-in-place concrete floor slab and walls. Its roof will be a composite construction of precast concrete planks with a cast-in-place concrete topping. Cosmic ray shielding will be provided by a 15 cm deep barite aggregate layer. The enclosure includes support facilities such as computer, control and electrical equipment rooms. The adjacent service building, built at grade, includes a loading dock, office, scintillator and mechanical equipment rooms. Adjacent to the loading dock is a tanker unloading facility sized to accommodate four trailers as well as safety and spill containment.

Pouring concrete against rock:
single-sided formwork solution from MEVA wins on technical counts
After the mud and base slab was poured, single-sided formwork was assembled to pour against the rock:

  • MEVA’s heavy-duty Imperial wall formwork not only offers the largest sized panel (12 x 8 ft, approx. 3.5 x 2.5 m) of any modular system, it also takes the most concrete pressure with a capacity of 97 kN/m2. The Imperial comes with US measures and is the twin system of MEVA’s metric Mammut wall formwork that is used outside North America.
  • The alkus all-plastic facing in all MEVA formwork panels is resistant to UV-rays, is impervious to water, climatic influences, heat or cold, remains stable under all conditions. Important for a job of this duration: the facing doesn’t rot and thus never needs replacing, saving the contractor unforeseen work flow disruptions.
  • The Imperial panels are supported by the STB 450 support frames. 150 cm extension units are added on top of the basic 450 cm support frame height. This simplifies adapting the height without disassembling the support frame.
  • KLK climbing brackets are employed both as working platforms and as support platforms for the formwork.
  • Triplex heavy-duty braces offer safe support for heights above 6 m. Their outstanding advantages: strength and modular flexibility.

The 12 m high single-sided walls were poured in two cycles with formwork lifts of approx. 7 m and 5 m. At height, the wall formwork rested on KLK support platforms that climbed the walls in 2.5 m lifts. The rebars were anchored to the rock on the outside of the walls using rock-anchors that were cast before rebar work.

The entire formwork equipment was delivered and serviced from MEVA Formwork Systems Inc. logistics center in Springfield, Ohio, USA.