Seismic performance assessment of timber braced frames with dowel connections and slotted-in steel plates: Drift- and energy-based performance indicators

Timber braced frames (TBFs) are an efficient seismic force-resisting system in mass-timber buildings, with brace-end connections governing the overall seismic response and system ductility. Despite their widespread use, the behavior of TBFs with dowel-type connections remains insufficiently characterized. More importantly, most existing studies have relied on the inter-story drift ratio as a proxy for system damage, without directly linking physical damage to overall performance. This study evaluates the seismic performance of TBFs with dowel connections and slotted-in steel plates using nonlinear dynamic analyses, incorporating both drift- and energy-based damage indicators for a moderate seismic region of Canada. The overall performance evaluation integrates a drift-based performance assessment framework developed by the Canadian Construction Materials Centre (CCMC) and an energy-based damage index calibrated from prior experimental data. Twenty archetypes were analyzed, varying in the number of stories, tier aspect ratio, connection type, and ductility class. Following CCMC guidelines, nonlinear response history analyses were conducted using ground motions scaled to 100 % and 200 % of the design-level earthquake to assess the performance of force-controlled elements and inter-story drift ratios. A damage-index-based fragility assessment was further conducted using a truncated incremental dynamic analysis. Overall, TBFs appear promising for use in moderate seismic regions of Canada, though their suitability in high-seismic zones remains uncertain.