Octagons place heavy demands

Ten fish farm tanks cast with Mammut 350 and hinged corners

Data & Facts

  • Project
    • Fish farm, Kragerø, Norway
  • Principal
    • Fossing Storsmolt AS, Helle, Norway
  • Contractor
    • Arne-Olav Tveit AS, Neslandsvatn, Norway
  • MEVA system
  • Engineering and support
    • Maxbo Teknikk, Norway

Easily adaptable formwork panels

Contractor Arne-Olav Tveit AS was mandated by a fish farm in Norway to build ten octagonal concrete tanks. Mammut 350 wall formwork was used in conjunction with MEVA hinged corners to create the precise geometry.

The new, 5 m high tanks installed on the rocky coast near the Norwegian town of Kragerø can hold some 8,000 m³ of water and many tonnes of fish. Four were built with an internal wall-to-wall distance of 16.5 m while the other six spanned 12.5 m. MEVA's Norwegian distributor Maxbo Teknikk supplied the formwork systems along with expert support.

Easily adaptable formwork panels
Instead of a commonly adopted steel or plastics solution, the customer Fossing Storsmolt AS opted for an extra-durable concrete fish farm tank. Formation of the 135° angles required for the octagonal shapes necessitated the incorporation of MEVA's hinged inside and outside corners. These are used for non-orthogonal angles and permit continuous adjustment between 60° and 180°. This allows the simple and precise adaptation of wall formwork, such as the 350 x 250 cm Mammut panels with their 8.75 m² contact area. All that was needed was to fit alignment rails using MEVA's handy flange screws to the intelligent multi-purpose profiles with their welded-in Dywidag nuts. The hinged corners were secured at the required angle with an easy-to-use locking device for frequently adopted configurations (70°, 90°, 120°, 135° and 180°).

The robust Mammut 350 heavy-duty formwork with a full-surface fresh concrete load capacity of 100 kN/m² significantly speeds up concreting operations. The 40 cm thick tank walls were rapidly erected with self-compacting concrete (SCC). ­Mammut 350 is fitted as standard with the high-grade alkus all-plastic facing. The form face is hardwearing, repairable with the same material and absolutely even while delivering a smooth, flawless concrete finish – a crucial requirement in this case to eliminate any risk of injury to the fish.

Given the geographical factors governing the site on Norway's craggy coastline and the unusual concreting geometry, this project called for in-depth formwork planning expertise. Maxbo Teknikk's technical department accordingly drew on its profound experience in formwork design and dimensioning. The solution involved the use of 350 and 250 cm tall panels in three different widths. The ten tanks were completed on time, in the specified quality and to the customer's full satisfaction.


Photos © Maxbo Teknikk