In wood construction, one of the most challenging parts of the design and implementation is the intermediate floor, which in multi-storey structures is the part between the roof of the ground floor and the floor of the upper floor, including the joints. The intermediate floor consists of several layers of different materials, the load-bearing structure is usually a timber-framed part and there is a wide variety of solutions and implementation methods. The design must take into account fire, acoustic and vibration characteristics. In practice, deviations from the design have been observed, e.g. in the vibration characteristics, which are on the one hand on the high side, and on the other hand certain methods of implementation are prone to construction errors. The guidelines for the design, measurement and classification of intermediate floors (Eurocode 5) are due to change in 2025 and the need for more efficient design and implementation and new, more cost-effective solutions is evident. The South-East Finland University of Applied Sciences has prepared a project package with Innovation and Knowledge Network funding together with the University of Tampere, Karelia University of Applied Sciences and the Natural Resources Institute of Finland, and each of these co-organizers will submit a separate application to the funder. In addition, the need to develop mezzanine floors and their design has been discussed with companies and design offices during the preparation process. The need to study, model and develop their solutions has been discussed with manufacturers of mezzanine solutions. The aim of the project is to improve the design, cost and material efficiency of wood hybrid mezzanine floors for wooden buildings. This will be achieved by combining user satisfaction in timber buildings, field measurements of timber buildings, laboratory testing of suspended floor solutions and consideration of these sub-sets in the optimization of solutions and design development. One objective of the project is to provide research data on the differences between measured and calculated characteristic frequency values. The project will create a new type of sizing tool for designers, to facilitate and simplify the design of suspended floors. The project will carry out extensive field measurements and user surveys on wooden buildings (public buildings, residential blocks) less than 10 years old or under construction, at different stages of construction. The measurements at different stages of construction will provide more detailed information on the effects of the shape, masses, joints, support and bonding of intermediate floors. The most common types of intermediate floor structures, such as CLT, open box slab and concrete, but also less common hybrid and beam structures will be targeted. Laboratory tests will be carried out to investigate in more detail the same types of structures as in field measurements. As a pilot, the project will build and test new structural solutions for intermediate floors, such as bonded, pre-stressed, multi-layered and composite structures. Prototypes of the new structural solutions can be manufactured in the Savonlinna laboratory. Existing and new structural solutions can be tested in several stages, starting with the testing of a single structural element and progressing to a complete structural solution.
