In English | ISSUE 3/2023

City block Lyyra was created by precision concreting

City block Lyyra was created by precision concreting
Photo credit: Arco Architecture Company Oy

The Lyyra project under construction in east downtown part of Helsinki will become a whole new city block on top of the Hakaniemi metro station. The developer in the large-scale Lyyra city block project is the Ylva Group owned by the Student Union of the University of Helsinki. The city block will provide facilities for hotels, commercial businesses and offices as well as housing designed for research scientists.

The construction of Lyyra started in January 2020 with the nine-storey office block completed in the spring of 2023. The two other newbuilds, a residential block and a hotel, will be ready in early 2024.

The project started with the demolition of two old office buildings from the lot. The location in a heavily trafficked city area meant challenges to worksite logistics. Deliveries of supplies and materials were restricted on a needs only basis.

The frames of the Lyyra buildings are steel concrete composite structures and cast-in-place structures are also high in number. All basement walls as well as lift shafts and stairwells were cast in place. 3D building information models were produced of all the structures.

Precast concrete products are also used abundantly in the project: wall panels, hollow-core slabs as well as staircase units and concrete ductwork. The facades of the Lyyra buildings feature concrete thin shell panels and a cladding of brickwork laid in place.

Extremely high standards of responsibility and decarbonisation were set for the worksite. Recycling principles were emphasised already at an early stage. A recycling rate of 97 percent was achieved.

There are no ground-supported yards in the Lyyra city block area. The minimalistic courtyards in Lyyra are located on the roofs of the buildings. For this reason, all work on the courtyards is scheduled to the end of the project.

Read the entire article in Finnish and see the images >>