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

Abstract

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.