Experimental and Numerical Study on the Overall Mechanical Performance of Dougong Group in Ancient Timber Structures of Qing Dynasty

Chinese ancient timber structures highly rely on the complex Dougong system for vertical load transfer. However, previous studies have mostly focused on individual Dougong, lacking a quantitative understanding of the synergistic load-bearing mechanism and system-level mechanical behavior of the entire Dougong group. This study investigates the one Dou and two Sheng Dougong group from the Qing-dynasty Jiayuguan architecture using three sets of full-scale experiments and refined ABAQUS finite element analysis (FEA). Test results indicate the failure sequence proceeds from the pingban-Fang to the column top, and finally Dougong. The overall macroscopic failure transitions from compression splitting of pingban-Fang in short spans to deflection-controlled failure in long spans. The load-displacement curves of the Dougong group fit a bilinear model, with vertical stiffness negatively correlated to span and intercolumnar Dougong count. FEA reveals a load-sharing ratio of approximately 9:1 between column-top and intercolumnar Dougong, with the tuo-Beam bearing roughly 75% of the load within the column-top set. Parametric analysis confirms span as the primary factor affecting vertical stiffness. These findings provide the first quantitative data on the synergistic mechanism of Dougong groups, offering a more reliable theoretical basis and computational approach for assessing and conserving Qing-dynasty timber structures.