Invisible joints between structures

Sweco Finland Oy was responsible for the structural engineering of the Pro Nemus visitor centre. All of the element models used in the design of the centre either had been used before or were applications of existing structures. The structure of the intermediate floor element had been used in apartment buildings, and the structure of the roof element had been used in hall buildings.

“We wanted to showcase wood products and various structural solutions in the visitor centre, which required good cooperation between the architect and the structural engineer,” says Jussi Björman, Director of Technical Customer Service at Metsä Wood.

The use of prefabricated elements means specific features for structural engineering. For example, the order in which the elements are installed must be planned carefully, along with the feasibility of joints and fastenings.

“In the visitor centre, the joints between structures have been implemented innovatively: the intermediate floor elements have been hung using their top panels. No holes or grooves needed to be made in the load-bearing structures, which made the elements very quick and easy to install,” says Björman.

Wood construction often involves various types of diagonal screw joints, which was also the case with this project. Steel parts screwed into wooden structures were used in joints between beams and columns. 

The building was designed by means of information modelling, using the Tekla Structures application for structural engineering and element design, and traditional AutoCAD for the design of the details.

On a tight schedule in a tent

Building a visitor centre in the mill area was a challenge in itself. The bioproduct mill attracts a great deal of interest and a large number of visitors throughout the year. For this reason, the construction site needed to be presentable at all times, despite the tight schedule.

“The schedule was by far the greatest challenge during the project. The decision to build the visitor centre was made in September, and the centre was scheduled to open in June. After the construction work had been completed, we also needed to allow time for building the exhibition,” says Tapio Vesander from Rakennustoimisto Alonen, who served as the site manager during the construction project.

The building was completed on schedule, in just seven months.

“I’m proud that we stayed on schedule despite the cold temperatures and other challenges. Around 50 people worked on the site, and they were divided into two shifts at an early stage. Effective planning played a major role in this project. The requirements for the precision of the work were exceptionally strict in the Pro Nemus project, as many technical details were designed to be left visible. Every millimetre counted,” says Vesander.

The construction work was completed in a tent, which offered weather protection from start to finish. During the construction phase, key criteria that affect the indoor climate include humidity, cleanliness and dust management.

Kerto LVL is a fire-safe building material

The wooden Pro Nemus building is an exhibition space with an area of around 1,000 square metres. Kerto LVL is a fire-safe material for the frame structure, as it behaves predictably and its exact charring rate is known. In the event of a fire, the surface of the material chars, which insulates it from heat and slows down the charring of the structure.

All of the facilities in the building are covered by a fire detection system. In addition, a functional fire dimensioning was prepared for the building, which made it possible for the architects to make better use of the spacious facilities allowed by Kerto LVL.  

An unprecedented exhibition about the story of Metsä

A masterpiece of modern wood architecture, the Pro Nemus visitor centre is a completely new kind of forest experience. By building an exhibition space that combines pure nature with virtual reality and experiences in conjunction with the bioproduct mill, Metsä Group wants to lead the way and establish itself as a strong forerunner of the bioeconomy.