Timber–Concrete Floor Slab Combines Compact Construction With Flexible Layouts
Researchers at the University of Stuttgart have successfully tested UniversalTimberSlab, a timber–concrete composite floor system for multi-storey buildings. The system combines a compact structural profile with flexible layouts and reduced concrete use. A first pilot building is planned in Oberkochen, Germany. According to the university, reinforced concrete floor slabs account for around 40 per cent […]
Researchers at the University of Stuttgart have successfully tested UniversalTimberSlab, a timber–concrete composite floor system for multi-storey buildings. The system combines a compact structural profile with flexible layouts and reduced concrete use. A first pilot building is planned in Oberkochen, Germany.
According to the university, reinforced concrete floor slabs account for around 40 per cent of buildings’ embodied carbon emissions. UniversalTimberSlab explores an alternative using renewable timber, material-efficient construction and circular design principles.
Compact Floors And Adaptable Spaces
The researchers describe UniversalTimberSlab as the first point-supported timber–concrete composite flat slab designed for long spans in two directions. Columns support the floor, removing the need for load-bearing partition walls. This allows architects to arrange spaces for retail, hospitality, offices or housing and adapt layouts when uses change.
Compared with conventional timber post-and-beam floors, which need deep beams for larger spans, the system reduces structural height by 30–70 cm. This could accommodate additional storeys within a given building height while maintaining ceiling heights. The university also reports potential façade area reductions of up to 20 per cent.
Prefabricated Timber And Digital Design
A new, patent-pending segmentation method enables both regular and irregular floor geometries. Prefabricated glued-laminated timber segments use straight laminations to simplify production. Their fibre orientation follows the flow of structural forces to optimise load-bearing capacity.
The team also developed AI-assisted digital design tools that generate detailed building variations and support optimisation. Moving a column, for example, reveals the implications for cost, slab height and sustainability during planning.
Full-Scale Load Test
The researchers built a 9 × 5 m demonstrator with spans of 8 × 4 m in three months. At 36 cm thick, it matched the depth of a reinforced concrete slab designed for equivalent loads and spans, while requiring approximately two-thirds less reinforced concrete.
During a public test at the Future Cleantech Festival in Remscheid in June, the slab carried 20 tonnes in addition to its own weight. The test assessed office-use conditions with finish loads of 1.4 kN/m² and a live load of 3.0 kN/m².
Measurements confirmed earlier finite element simulations. Maximum deformation reached 12 mm, while a natural frequency above 8 Hz met the stated deflection and vibration requirements for multi-storey buildings.
From Demonstrator To Pilot Building
Oberkochen’s planned Zukunftsforum will provide the first pilot application: a three-storey, 1,400 m² building containing exhibitions, workspaces, makerspaces, workshops and laboratories. Further development remains necessary before wider deployment.
Funded through the European Innovation Council’s Horizon Europe EIC Pathfinder programme, the project forms part of Stuttgart’s IntCDC research cluster. It involves the university’s computational design, structural design, acoustics, building physics and construction materials institutes, its Materials Testing Institute, and BUILT CoLAB in Porto.
Industry partner HASSLACHER Group manufactured the demonstrator’s timber segments, which Dünschede Holzbau installed in two days. By using established timber manufacturing expertise, the researchers aim to support transfer into larger construction projects.
Source & photos: University of Stuttgart