The University of Helsinki reused load-bearing structures for the first time
The University of Helsinki’s Learning Centre Aleksandria reopened in the summer. In addition to the pleasant soundscape and ergonomic spaces, the renovation work promoted the circular economy. Sweco’s structural engineers helped to reuse old glass and steel parts as load-bearing structures.
Renovation Structure Design of Learning Centre Aleksandria
Kaisa House, i.e. the extension of the Helsinki University Library, Learning Centre Alexandria opened in the summer of 2025 renewed. The changes were based on the development of teaching methods and changes in study methods, for example as a result of the coronavirus.
“The 20-year-old building already had a lot of things, such as desktop computers, that no longer met the needs of students,” says Anne Pitkänen, Construction Engineer at the University of Helsinki. As distance learning increases, students need more and more self-study spaces.
Sweco’s structural designers were responsible for the main structural design of the repairs and the steel structure design. Structural designer Tommi Mutanen also participated in pop-up workshops, which charted the wishes of users in the spirit of co-creation.
“Tommi was one of the few designers who emphasised at every stage that we are not just doing great new things, but spaces for the users. That was memorable,” Pitkänen says. The project had a tight schedule, but the entire design team had the necessary stretch.
Glass and steel parts were reused as load-bearing structures
The client emphasised the circular economy in the renovation structure design. “The University of Helsinki has ambitious sustainability and responsibility goals, but because no renovation was carried out now, it was not possible to apply for environmental certificates. We wanted to find other ways,” Pitkänen explains.
Mikko Horkonen, Head of Unit at Sweco, thinks it is great that the university did not settle for reusing only furniture and surface materials. “The university also reused old glass and steel structures as load-bearing structures for the first time.”
The necessary parts were obtained when the old staircase, which was located in a remote area, was demolished. The new staircase was designed in a prime location under a glass roof. “About 70 per cent of the load-bearing steel parts were reused, and all of the glass steps of the staircase remained intact,” says Tommi Mutanen.
Safe reuse of structures
The reuse of load-bearing structures was carefully prepared. Sweco’s structural engineers photographed the interior first with Matterport camera. The site-specific approval of the old structures also required an expert statement and a report to the authorities on the suitability of the materials.
“When reusing materials, you must always be careful to ensure indoor environmental conditions, for example, but this time it was also a question of the load-bearing capacity of the structures,” Mutanen emphasises. He thinks that steel and glass are well suited for reuse. “The material properties assumed by the design standards are similar now as they were in the early 2000s, so the load-bearing capacity calculations were comparable.”
The reused glass steps of the staircase are made of frosted milk glass so that it feels safe to step on them. The designers also made sure that the slender structure does not vibrate. The glass railing is supported by architectural cladding mesh, which was used in a rare way. The mesh not only hides the steel structures, but also serves as part of the railing.
“We had to tension the net as a rope-like structure so that it wouldn’t flex too much,” Mutanen says. The staircase, which is about 17.5 metres high, has a glass performance platform, which was reinforced from below with steel cables. “This way, we avoided more visible load-bearing structures, such as pillars.”
Reuse celebrates Alexandria’s historical roots
The steel-glass staircase now offers a new passage and at the same time a magnificent view through all five floors of Alexandria. The staircase also connects the future and history. The staircase is bordered on one side by the old plastered exterior wall of the Kaisa House, to which a new acoustic plaster was added during the renovations to improve the soundscape.
“We were able to support the architect in the implementation of a magnificent project and contribute to the University of Helsinki’s wishes for the reuse of structures with its diverse expertise in steel and glass construction,” Horko says with satisfaction.
The renovated Aleksandria offers students, among other things, 500 different workstations with electric desks, group work spaces, break exercise points and a rest room. There are also more spaces dedicated to quiet work than before. A pleasant sound environment has been created in the rooms, which were originally in the same sound range.
“One of our biggest successes is the acoustics. The new partition walls and structural technology played a major role in this,” says Pitkänen. The steel-glass staircase has not remained a specialty that can only be admired from afar. “Users have already embraced it.”