Experimental and Numerical Investigations of Groove Connections for a Novel Timber-Concrete-Composite System

The development of hybrid structures is constantly being pushed forward because of the need for more efficient components that incorporate multiple functions. Structural requirements lead to state-of-the-art timber-concrete-composite (TCC) floor systems, which consist of a concrete layer on top of timber beams or decks. In bending, the TCC concrete layer is in compression and the timber is in tension. When multifunctionality requirements such as building physics or fire protection are added, other solutions of the structural form of hybrid systems can emerge that challenge common engineering conceptions. This paper presents research on the connection system of a novel TCC setup that integrates thermal and fire protection functionality, in which timber beams are placed at the top and a concrete layer at the bottom. The results from full-scale bending tests, and shear and tension tests on a subsection of the system, show that the grooves cut into the timber beams transmit the shear forces and sufficiently connect the concrete deck vertically to the timber. Subsequently, the structural behavior was numerically modeled and the agreement between experimental and numerical results allow for the validated model to be used for geometric optimizations, and predicting the performance of optimized systems.