ABSTRACT

This paper studies the influence of degraded connections on dynamic characteristics, seismic response, and seismic fragility behaviors of traditional Chinese timber-framed buildings. Numerical models are developed based on the extended distinct element method, and calibrated with 1:3.52 scaled shake-table test data. The influence of fracture and wood aging on the performance of both mortise-tenon joints and Dougong brackets connections is discussed. A set of 20 ground motion records are selected for an incremental dynamic analysis, seismic behaviors, and fragility assessment. Results indicate that considering 0.75 times and 0.85 times degradation of mortise-tenon joints, natural frequencies are reduced by 8%, and 4%, respectively, and 4%, and 2% for Dougong brackets connections, respectively. The maximum acceleration response is reduced at most by 1.8% and 0.9%, respectively, and the maximum relative displacement is promoted by 7.3% and 5.3%, respectively. In addition, for a peak inter-structural layer drift of 1/442, 1/148, and 1/48, seismic intensities corresponding to median probabilities of exceedance of the structure with 0.75 times degraded performance of mortise-tenon joints are reduced by 32%, 16%, and 9%, respectively, and 14%, 6%, and 3% for Dougong bracket connections.