THE EXPERIMENTAL STUDY ON STIFFNESS OF DOUGONG IN CHINESE HISTORIC BUILDINGS

A kind of extremely unique built-up appears during the Chinese timber structure system developing process. Its name is Dougong. It has excellent quality of anti-earthquake. Through the low cyclic loading experiment of single Dougong, two Dougongs and four Dougongs, the degrading rule of lateral stiffness of Dougong have been studied. According that, the hysteresis curve and skeleton curve of force displacement are researched and the formula of resilience model and mechanical model are established. From the experiment, we can see that slippage is the main deformation of Dougong. Energy dissipation because of frictional slippage is an important reason for the excellent seismic behavior of ancient wooden structure. Hysteretic loops of Dougong assume to be parallelogram-type. Experiment agrees with theoretic analysis, 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 the changes in stiffness of Dougong, and adapt to the research on static load delivery as well as dynamic structural analysis and calculation of similar wooden structure. These basic theory provide a theoretical basis for the study on the seismic performance, remedy and strengthening of ancient wooden structures. The result of test provides very useful suggestions to modem building construction.