Wood-Wood System Connection for Elements - A Hook-in System. A Fire Protection Case Study of a Multi-storey Timber Building

In timber construction, many wood-wood connections have bar-shaped components. As yet, for cross-laminated timber (CLT), wood-wood connections are still not available. The Department of Timber Construction at the University of Innsbruck has therefore developed the “double dovetail tenon”, a system connector made of laminated veneer lumber (LVL) made of spruce. It consists of two dovetail-shaped tenons that are rotated 180° at their overlapping surface. With this system connector, the orientation of the veneers and the inclination of the flank surfaces can be varied. The fire tests are carried out analytically, based on existing research from the literature and fire tests already investigated on metal and wood joints of similar size and joint shape. The fire protection investigation is carried out in two steps: Observation of the components of the system connection (connectors, CLT) as well as the combination when installed. A significant difference to conventional wall-ceiling-wall connections is that the ceiling is vertically inserted into the wall element. The system connector is fully integrated into the components to be connected. Due to assembly tolerances and wood shrinkage/swelling, a gap must be allowed for. Precision deviations due to the CNC joinery must also be taken into account. These and other considerations are investigated using the example of a multi-storey timber building with different installation options for the system connection. In contrast to metal system connectors, the wood connector does not heat the entire connector, but only the parts of the connector directly exposed to the flames.