Behaviour of steel perforated plate seismic fuses in timber end brace connections

Perforated steel plates used as fuses in timber end brace connections (EBC) effectively dissipate seismic energy and minimize damage to the structure, with the added benefit of being replaceable post-seismic events. This study presents full-scale experimental tests on such connections. In the first phase, six configurations with circular and oval perforations were tested. The outcomes indicated that shear-yielding failure dominated at relatively small displacements, accompanied by minimal elastic bending and slight plastic hinge rotation deformations. However, there was a notable enhancement in ultimate deformation and energy dissipation for the oval perforations. Consequently, a second phase of the study was conducted to explore alternative perforation patterns and their corresponding failure mechanisms. Plates with long oval perforations exhibited the highest ultimate deformation of 14.4 mm, showing a 20 % increase compared to other patterns, along with an average over-strength factor of 1.4, and a ductility ratio of 15. These findings suggest that the preferred fuse-yielding mechanism is flexural, achieved using long oval perforations. The results confirmed that perforated steel plates function effectively as fuses, providing reliable yield mechanisms while protecting the integrity of the timber members. • This study investigates the seismic performance of timber end brace connections (EBCs) equipped with perforated steel plates acting as replaceable fuses, emphasizing energy dissipation and structural resilience under cyclic loading. • Phase 1 experiments examined circular and elliptical perforations, revealing that elliptical shapes achieved superior deformation and energy dissipation through a combination of shear and flexural yielding mechanisms. • In Phase 2, various perforation configurations, including long oval and diamond-shaped patterns, were tested to explore alternative yielding mechanisms, such as axial and flexural yielding. Long oval perforations exhibited the highest deformation capacity, achieving ultimate deformations of 14.4 mm and a ductility ratio of 15. • The study demonstrated that perforated plates with flexural yielding provide the most effective failure mechanism, localizing damage within the fuse and preserving timber elements. This ensures cost-effective and sustainable post-seismic recovery by enabling easy replacement of damaged components. • Results highlight the critical role of perforation geometry in enhancing stress concentration, ultimate deformation, and energy dissipation. Long oval perforations were identified as the most promising configuration, though further parametric studies are recommended to optimize performance. • Findings contribute to the development of ductile, energy-efficient seismic systems for timber-braced frames, advancing structural resiliency and sustainable design practices.