An experimental study of the combined hysteretic behavior of dougong and upper frame in Yingxian Wood Pagoda

Dougong and beam-column frame are two major structural components in ancient Chinese multi-layer wooden structures. A dougong layer is composed of several dougongs linked in the horizontal plane, and connects the upper and lower layers of beam-column frames in the vertical direction, which indicates that the connection behavior between the dougong layer and the beam-column frame layer is crucial to the overall mechanical performance of the multi-layer structure. In this study, a full-scale specimen consisting of a dougong layer and a upper beam-column frame layer was fabricated, and two models were assembled with the frame infilled with doors or diagonal braces. Two pseudo-static tests were performed on the models, and the hysteretic behavior and the compatible working mechanism were studied. Test results show that the hysteresis curve of the door model is symmetric and plump, and has good ability in dissipating seismic energy, while the sudden drops of reaction force are observed in the hysteresis curve of the brace model due to the slip of the braces. The individual displacements of the dougong layer and the upper beam-column frame layer demonstrate that the stiffness ratios between them are 6.5–14.3 in the door model and 3.8–6.5 in the brace model, therefore the overall mechanical behavior of the structure is dominated by the upper beam-column frame layer.