Horizontal Earth: A Novel Perspective on the Shear-Bond between Timber and Earth in Bending-Stressed Components

The development of innovative and sustainable building materials is becoming crucial in the construction industry, which is increasingly focusing on environmentally friendly and circular solutions to reduce its ecological footprint. The use of locally available and renewable resources, along with the reinterpretation of traditional building systems, can contribute to further establish the use of ecological and circular materials in construction.

Horizontally spanning structures offer significant opportunities for resource conservation, as they typically require large amounts of material for their realisation. Earth, a widely available yet often overlooked building material, possesses acceptable compressive properties and is traditionally used for walls, such as wattle and daub. Combining earth with timber, which resists tensile forces effectively, broadens its applications to include elements subject to bending stress as slabs. This strategic material pairing also lowers the need for wood - a crucial aspect given its limited availability.

The application of the hybrid material system in bending-stressed components poses several technical challenges, the most significant being the need for efficient shear force transfer between timber and earth to guarantee a reliable material bond. ... mehrTo analyse the shear transfer capacity of the timber-earth-composite, several push-out tests were conducted - a proven method for timber-concrete-composites. Various types of fasteners, such as screws and wooden shear connectors, were implemented to ensure efficient force transfer between the materials. The resulting bond characteristics were evaluated for scalability in two full-scale components.

Various modelling approaches, including the γ-method and the truss model method, have been investigated, with particular emphasis on the truss model to capture the non-linear behaviour of earth materials and the bond conditions identified through component testing. The objective is to establish a viable calculation method that facilitates the scaling up of timber-earth slab spans, allowing for the identification of optimal configurations of material arrangement and thickness, and thereby enhancing their potential for real-world applications.

Timber-earth-components represent a sustainable composite material that not only meets structural requirements but also offers advantages in sound and fire protection, as well as thermal mass, therefore providing a promising alternative for the construction industry.