Demountable wood-concrete composite elements from Brüninghoff
12.03.2025
Figure: Brüninghoff
The construction industry is facing a transformation: sustainability and resource conservation are no longer just communicative buzzwords, but an urgent necessity. Innovative circular concepts such as the demountable wood-concrete composite elements from Brüninghoff show how SMEs can act as drivers of transformation. These ceiling elements are therefore not only an example of technological innovation, but also of forward-looking construction practice that favours reusability.
The SME construction industry is extremely efficient, flexible and can adapt quickly to changing market conditions. This agility makes it possible to react efficiently to customer wishes and market requirements. In addition, SMEs are often highly innovative, particularly in the application of new technologies and processes - and generally attach great importance to customer satisfaction and responsible corporate governance. So much for the theory. The Brüninghoff Group impressively demonstrates what this looks like in practice and how this pioneering role can be fulfilled with the further development of hybrid wood-concrete composite elements into a dismantlable, practical system. The hybrid ceiling elements can be given a second or third life cycle thanks to the sophisticated deconstruction concept. The uncomplicated removability is achieved through newly developed reversible component connections, an optimised Kerve and special connectors as lift-off protection. This makes it easy and economical to reuse the entire element while retaining its shape and properties, as well as to separate and recycle wood and concrete according to type.
Long-term thinking
Long-term, future-orientated thinking is deeply rooted in Brüninghoff's corporate DNA. With this in mind, we are aware of our responsibility to society as a whole to develop sustainable construction practices that reduce the consumption of resources and minimise environmental impact. After all, the construction industry in Germany is responsible for a considerable proportion of resource consumption. Smooth, high-quality dismantling and reusability are crucial and must be taken into account as early as the planning stage of buildings or the production of prefabricated components. This approach not only promotes the conservation of resources, but also economic efficiency by reducing waste and improving material efficiency.
Clearly structured innovation process
The innovation process is clearly structured within the Group and actively integrates employees into the idea generation process. Through a systematic approach and accompanying workshops, ideas are repeatedly developed into market-ready products. These processes are part of the innovation culture, which also focuses on flexibility and diversity. This not only encourages the creativity of employees, but also enables the continuous development of products and processes. At the same time, Brüninghoff has close links with universities and research institutes. This networking is also evident in the further development of the HBV ceiling - it is based, among other things, on a master's thesis written by Christina Freese at the University of Graz. Brüninghoff itself has been involved in the production of hybrid ceiling elements for many years, so that the cycle-orientated further development is based on extensive practical experience with regard to the connecting elements between wood and concrete.
Practical large-scale test
Brüninghoff carried out a comprehensive large-scale test to check the practical suitability of the enhanced HBV floor slabs. Three ceiling elements were installed under real conditions - including the grouting work on joints and column connections - and then dismantled. Two elements were successfully reused in a customer construction project, while the third element was successfully recycled as a single type. The test showed that damage-free dismantling and subsequent reuse as a whole as well as recycling of the materials are technically possible and economically viable. It took around two years from the transfer of the project from innovation management to a practical and marketable component - a very short time for an innovation process of this scope.
Agility and networking
The separability of the ceiling elements is made possible by an optimised Kerve and the removable anti-lift device developed in collaboration with Reisser Schraubentechnik GmbH. A sleeve protects the screw thread in the concrete from sticking, while the force is transmitted via a washer. The screw head cover makes it easier to locate and fully expose the screw drive. Once the anti-lift device has been removed and the wood and concrete have been separated, the broken concrete can be used directly as recycled aggregate in the production of resource-saving concrete (R-concrete). The separation of wood and concrete was carried out in co-operation with Heermann Abbruch & Recycling GmbH. The wood is available for high-quality material reutilisation, the production of wood-based materials or, ultimately, for energy generation. By working with partners such as Reisser Schraubentechnik, Heermann Abbruch and Nienhaus & Thielkes Betontrenntechnik, Brüninghoff has increased the efficiency and effectiveness of its dismantling processes. Prof Dr Anja Rosen, architect and DGNB auditor at C5 GmbH, accompanied and evaluated the deconstruction tests using the Urban Mining Index she developed.These collaborations make it possible to develop innovative solutions that make the dismantling and reuse of construction elements even easier and more economical. Networking with specialised companies promotes the transfer of knowledge and the development of new technologies that optimise the entire construction process.
Close relationship with the client
In October 2024, the two ceiling elements prepared for reinstallation were installed on a construction project in Schönberg (Lower Bavaria). Here, Sesotec GmbH is expanding its capacities for the development and manufacture of foreign object detection systems. Brüninghoff is acting as general contractor for this construction project. The fact that the dismantled HBV ceiling elements could be reinstalled here is also due to Brüninghoff's close relationship with the client and the trusting, transparent communication between all parties involved in the project. Thanks to the dismantling concept developed, the ceiling elements could be removed from the test stand undamaged. This means that there is no difference between reinstalling elements that have already been used and installing new ceiling elements. When dismantling from an existing building, only the deflection of the ceilings due to long-term effects must be taken into account in the planning of the new building. In the case of the third ceiling element, which was dismantled into its timber and concrete components, load-bearing columns could be made from the glulam beams by removing the top slats of the beam and planing and bevelling the cross-sections.
Legal framework for the built standard
Brüninghoff demonstrates how agility, innovative strength and proximity to the market and customers contribute to high performance and realisation strength. In order to promote the use of demountable components, a clear legal framework and practical testing and qualification processes are required. Taken together, these must ensure that reused components meet the same safety and quality standards as new ones. Establishing such standards not only increases the acceptance of reused components, but also ensures legal certainty for all parties involved. With the circular construction concept, the Brüninghoff Group is not only ensuring its success in future competition, but also demonstrating that the company is taking on a pioneering role in the development of circular construction concepts and in a circular construction industry - and that circularity can already become the built standard today.
CONTACT
Brüninghoff GmbH & Co. KG
Industriestr. 14
46359 Heiden/Germany
+49 2867 9739-0
