Experimental Study on Stiffness of Dougong in Chinese Ancient Buildings

As an important structural member in Chinese timber structure system, Dougong has an excellent capability in earthquake resistance. Through low cyclic loading experiment of single Dougong, two Dougongs and four Dougongs, the degrading rule of lateral stiffness of Dougong was studied. According to that, the hysteresis curve and skeleton curve of force displacement were researched and the formula of resilience model and mechanical model were established. The experiment data show that slippage is the main deformation of Dougong. Energy dissipation due to frictional slippage is an important reason for the excellent seismic behavior of ancient wooden structure. The shape of hysteretic loops of Dougong assumes to be parallelogram. Plump area of hysteretic loop accounts for its excellent energy dissipation performance. The mechanic model of Dougong belongs to linear strengthen elastic-plastic model. Both the fitting equation of force-displacement and resilience model reflect stiffness changes of Dougong. These basic theories provide a theoretical basis for the study on the seismic performance, repair and strengthening of ancient wooden structures.