Interest in building with timber is growing and players in the construction industry are choosing to distinguish themselves by taking on the challenge of building really high with timber, up to and above 20 floors. The challenge drives development and advances timber construction. In a series of projects, RISE together with academia, building system suppliers, consultants and clients have studied the challenges, developed and described technical solutions for a number of them.
Taller buildings with timber frames are still uncommon, although examples as high as 20 storeys can be found in Sweden, but buildings up to eight storeys are very widely built. Building high, regardless of the materials used, poses some new challenges compared to building lower buildings. Challenges drive the development of construction in timber, which benefits construction in general for the industry.
For high-rise timber buildings, the challenges are mainly related to stabilisation, fire safety and production aspects. The "High-rise timber buildings" project has established that it is entirely possible to design and build 22-storey buildings with a timber frame that meet the requirements for stability, vibration and fire safety. Two critical aspects were fire safety and the risk of movement caused by wind loads at the top of the building. RISE and the consulting companies BRIAB and Brandskyddslaget have developed guidelines for fire safety challenges that have been developed to support similar design processes. Wind-induced movements proved to be a challenge already at 10-12 storeys, but became manageable even for 22-storey buildings with the help of related projects. The magnitude of wind-induced movements depends on the weight, stiffness and damping of the building, but due to the few other examples of tall timber buildings, there is great uncertainty as to how large the damping can be. To increase the understanding, it was studied in a European co-operation project, with RISE as coordinator, by evaluating the damping in eight large timber buildings in Europe.
In Sweden, Linnaeus University and RISE carried out measurements in a building in Mariestad to evaluate the properties of the building with respect to wind load. Results from the project will be summarised in recommendations for how calculation models for wind load of tall buildings should be designed to best describe the actual load. Funding Formas, Vinnova, Energimydnigheten and ForestValue.
Further reading
Tall timber buildings - concept study (Link)
This is an article from our magazine Trävärden, view it here! (Link)
