Monotonic mechanical performance of traditional timber mortise-tenon joints: effects of joint type and dowel configuration

Comparisons of traditional timber joints are hindered by inconsistent loading and parameter definitions. This study examined whether joint type and dowel details affected peak capacity and initial stiffness in different ways. Sixteen full-scale Chinese-fir joints were tested under one monotonic protocol; thirteen records were retained after data-quality screening. A unified procedure extracted peak moment, initial rotational stiffness, nominal yield indices, recorded rotation limit and monotonic deformation work. Concealed circular dowels increased L-joint peak moments by 7.8–12.9% relative to sound undoweled specimen A7. The undoweled peak-capacity CV of 37.8% is strongly influenced by A8′s pre-existing fabrication defect and cannot characterize variability in sound joints. Centred and eccentric circular dowels had similar peak capacities but different initial stiffnesses. Single-specimen square-dowel comparisons suggest a pronounced stiffness penalty; the concealed square specimen retained a comparable peak moment. The main finding is that capacity alone does not characterize rotational restraint: differences in contact mobilization may alter stiffness without a comparable capacity change. Configuration-specific empirical coefficients provide preliminary comparison data rather than design values. The evidence is limited by small replication, single-specimen configurations, fixed mortise geometry, Chinese fir and monotonic loading; it does not establish seismic ductility or cyclic energy dissipation.