innovative wood-concrete girder
Mobilis and ipv Delft are developing a circular viaduct of wooden beams with a prefabricated top layer of recycled concrete. It is one of ten proposals within an SBIR process of Rijkswaterstaat (the Dutch irectorate-General for Public Works and Water Management). SBIR stands for Strategic Business Innovation Research (SBIR) Circular Viaducts. Rijkswaterstaat’s call was answered last year by 32 parties, 10 of which are now
engaged in feasibility studies. Later this year, three parties will actually be allowed to develop a prototype.
The wood-concrete beam system is a direct alternative to the current prefab concrete beams. The system consists of laminated wooden beams with a deck of recycled concrete. The beams are held together by tensioning them together with transverse prestressing.
Cantilevered precast concrete edge elements protect the wood against weather influences, which ensures a very long lifespan of one hundred years.
Application of the innovative modular system has significant advantages. In this way, an MKI reduction of 40 percent is achieved. The environmental cost indicator (MKI) shows the environmental impact and shadow costs of a product. The system owes its good MKI score to, among other things, the use of wood, a renewable material that absorbs CO2 instead of emitting it, and recycled concrete. The weight of an arbitrary viaduct will be approximately 20 percent lower, which will lead to a reduction in the foundation material. In addition, the product is modular and the various elements can be completely separated and reused after use. An additional advantage of the modular system is the short implementation time.
TBI company Mobilis and ipv Delft are working closely with engineering firm Miebach (wooden bridge construction), Rutte Groep (recycled concrete) and Heko Spanten (supplier of wood construction) in the development of their version of the circular viaduct.
(Innovative Materials 2021 2)