Timber-Earth – Structural Behaviour of a Composite Material for Horizontal Building Elements

Abstract

Timber-earth hybrid systems for horizontally spanning structural elements offer a sustainable, circular-oriented solution with additional benefits related to sound insulation, fire resistance, and thermal mass. By leveraging the ecological advantages of earthen construction - such as low embodied emissions and material reusability - these systems present a viable alternative to conventional methods and contribute to a reduced environmental impact in the construction sector.

This paper focuses on integrating earth as a load-bearing component to ensure effective load distribution between timber and earth. A key challenge in bending-stressed timber-earth systems is achieving efficient shear force transfer for reliable structural performance. To address this, a series of push-out tests were carried out, drawing on established approaches from timber-concrete composite research. The scalability of the resulting shear connection properties was then examined through tests on full-scale (1:1) components employing various shear connector types. For an initial numerical and computational assessment, commonly used design methods from timber-concrete composite systems - such as the γ-method and the truss model method - were employed.