Development of Comprehensive Testing Procedures for High-Performance Bonded-in Rods

Abstract

Bonded-or glued-in rods are a highly efficient fastening technology. The complexity of the interaction of different materials in the joint (adhesive, rod, and wood) and non-linear stress distribution along the bondline present special challenges for the precise characterisation of the strength and stiffness properties relevant for the design. The existing test standards and protocols specify only the bare minimum for the utilisation of these connections. The following aspects need a more detailed consideration in test specifications: rods in different wood-based products; impact of spacing and end/edge distances; group effects; quality assurance; fatigue; impact of environmental conditions, fire resistance, etc. In the paper, a detailed state-of-the-art regarding testing of bonded-in rods is given and the different aspects with need for further test development are discussed. Proposals are also made on how to better characterize experimentally the properties and behaviour bonded-in rods and on how to fully utilize their potential in design.