The steel frame of Turku market square pavilions leaves room for graceful and airy architecture
The award-winning pavilions at Turku market square are a prime example of hybrid construction. The steel and wood pavilions divide the market area and connect seamlessly to the underground structures of the car park. The structural design of both was Sweco’s responsibility.
Three pavilion buildings were completed at Turku market square in 2022, with structures that combine steel, wood, concrete and glass. The pavilions divide the square into human-sized parts like natural trees, where you can stop and enjoy the atmosphere and services. The pavilions include business premises, restaurants and cafés.
“Architecturally, the pavilions are far from straightforward concrete construction, which is why we had to think very carefully about all the possibilities of steel structures,” says Jari Tschernij, chief designer of the project from Arco Architecture Company. The architecture of the pavilions was designed by Schauman & Nordgren Architects.
The pavilions and Toriparkki function as a whole
The pavilion buildings are structurally and functionally tied to the Market Square’s underground parking garage and its superstructures. “That is why it was good that we were already responsible for their structural design,” says Mikko Sirén, Unit Director at Sweco.
The pavilions were taken into account in the structural solutions of the previously completed Toripark, which helped with the coordination, according to Tschernij. The stairwells, lifts and underground ventilation of the parking hall were discreetly adapted to the shelters of the wood-clad pavilions.
“Functional penetrations were also found for a huge amount of building technology in the post-tensioned upper floor slab of the parking garage, which showed the competence and cooperation of Sweco’s different teams.”
The architecture was realised almost perfectly with steel and wood structures
Tschernij considers the site as a whole to be very demanding. Already in the plan, a very limited space and size were defined for the pavilions. “Combined with such a slender structure, it would be a tricky equation even in a larger site.”
In order to implement the architecture, a wide range of materials were utilised in the structures. The stairwells are made of concrete, and most of the load-bearing frame is made of steel. In addition, the graceful and low architecture of the facades was implemented with more than 2,000 glulam beams. “The façade cladding is made of glulam, and finding a functional solution required eight different alternatives,” Sirén recalls.
According to him, the most demanding places were eaves projections up to four metres long and the total stiffening of the load-bearing structure. Stiffening structures could not be used in the wide glass walls. The steel felt roof was merged into the walls like a tree canopy, and the low upper floor structure kept the overall look of the buildings light.
“We had to find room for building services in a tight form, which is why the roof structures were designed parametrically. It made it possible to modify the structures quickly, both in terms of design language and technical building services,” says Sirén.
Tschernij takes his hat off to Sweco’s structural designers, who succeeded in using steel to make the architecture graceful and airy. In restaurants, for example, only four slender pillars are visible, which fade almost completely behind the glass walls in black tones.
“When the structures were kept as low as possible, it was challenging to completely hide the building services behind glulam cladding, but here too the versatility of steel was proven.”
Although there were plenty of challenges in the project, they were solved together. “From the point of view of the chief designer, the client, contractors and designers worked together brilliantly and valuably in the project, which solved the issues!” Tschernij praises.
The renewed Market Square and its pavilion buildings opened in early autumn 2022. The pavilions at Turku Market Square have been chosen as the Steel Structure of the Year (2022) and the winner of the Wood Day general vote 2023.