The world’s tallest timber building (85.4 metres) is groundbreaking for more than just its height. When Mjøstårnet was to be built, Moelven employed a completely new and untested assembly technique.
“Outsiders may perhaps think that there is great risk involved in using a new assembly method on such a large and prestigious project. However, following many years of development, we were ready to take a new step,” says Rune Abrahamsen, director at Moelven Limtre.
Lego for grown-ups
Mjøstårnet is Moelven’s second world record in terms of tall timber buildings. In 2014 the apartment building Treet was completed in Bergen. The structure, with a height of 51 metres across 14 storeys, was first assembled at the factory in Moelv before being transported to the building site for final assembly. However, with Mjøstårnet the beams went directly to the building site, without any form of trial assembly.
“This is accuracy taken to the extreme. The beams arrived fully processed at the building site, and fit the structure down to a millimetre. There was no scope for errors in the assembly. The principle almost like Lego for grown-ups. All of the pieces have specific place and must fit,” Abrahamsen says.
This new construction method ensures that erecting buildings such as Mjøstårnet is much faster. When the world’s tallest wooden building was completed in March 2019, Moelven had hoisted several hundred glulam beams into place in the structure over the course of 10 months.
“This assembly method is very efficient in terms of time, and will become the new standard for glulam structures like this,” Abrahamsen says.
Several storeys in one hoist
The actual assembly took place using a large crane at the building site. External scaffolding was not used. When Moelven has hoisted the glulam structure into place, several storeys have been hoisted at once.
“We’ve hoisted 4-5 floors at a time. Then we complemented them with Trä8 floor elements (see fact box) from Moelven Töreboda. These are really huge structures, and it’s an incredible feeling to watch almost 20 metres of the building’s height being hoisted into place in one go. Both the building and our pride grow in tandem,” says Lars Ivar Lindberg of Moelven Limtre, who was responsible for assembling Mjøstårnet.