Mechanical performance and design challenges of wooden fasteners: a critical analysis of evaluation methods and standards

Abstract

Wooden fasteners are gaining increasing attention due to their potential to enhance automation in wood processing, recyclability, sustainability, and producing Engineered Wood Products free from metal fasteners and adhesives. The mechanical response of wooden fasteners differs significantly from conventional metal fasteners. This distinct behaviour necessitates the development of specific guidelines and standards for assessing and designing wooden fastener connections. Current standards, such as the Eurocode and National Design Specification, along with existing research, offer empirical equations that are not fully applicable to wooden fasteners. Proper evaluation of wooden fastener joints requires the determination of key mechanical properties, including maximum bending moment, maximum bending strength, shear strength, and embedment strength. However, the flexible nature of wooden fasteners and their size and geometry make the determination of these properties challenging. This review critically examines the mechanical properties of wooden fasteners, factors influencing their performance, testing methodologies, failure modes, deviations from existing metal fastener standards, and emerging trends and challenges in the design of wooden fastener-based connections. This critical comparative review of wooden fasteners and their quantitative evaluation of deviations from steel fasteners provides valuable insights that will be helpful for future standards and innovation related to wooden fasteners.