Abstract：To investigate the influence of different fire treatment on the fire performance of Dougong of Qing-style timber buildings, 3 specimens exposed to fire were experimentally studied. The single-qiao-single-ang five-step flat Dougong was tested under the wood crib fire. It is found that the single-cai-gua arch, the single-cai-wan arch and the xiang arch were first ignited and the combustion duration was the longest, resulting in serious charring. The flame of the burning components in untreated Dougong specimen superposed together with the wood crab fire, inducing relative high flame. The components in Dougong specimen with fire retardant coating impregnated materials were not ignited. Temperature at different locations increased with the fire duration time. Different specimens had similar internal temperature development at the same distance to the edge. The charring along the span of the components was not evenly distributed, which depended on their space locations and initial geometry. The charring rate of Qiao, single-cai-gua arch, xiang arch, single-cai-wan arch and external dragging beam at both horizontal and vertical directions was relatively high. The charring rate of specimens without treatment was about 0.5～1.0 mm/min, while that of the specimens with fire retardant coating treatment on the surface was about 0.1～0.9 mm/min. And the charring rate of the specimens with fire retardant coating impregnation of the components was about 0.1～0.7 mm/min.
