First actually Dou Gong is a unique interlocking wooden bracketing system. It is one of the important element in traditional Chinese architecture.
It is consist of many interlocking parts of timber to form a bracket.
The pieces are fit together by joinery alone without glue or nail.
Dou Gong are widely used in the ancient Chinese around 770-476 BC and developed into a complex set of interlocking parts by its peak in the Tang and Song Dynasty periods.
FUNCTION :
-Transmit the weight of the beams or roofs which are above them by transferring the loads to the columns.
Can be found only in the most magnificent buildings such as palace and temple halls.
The numbers of layers of these bracket structures depended on the importance of the buildings.
Multiple Dou Gong made these structures very earthquakes-resistant and for your information it can hold the wood structure together even though brick walls would collapse in the same earthquake.
This system helped ancient buildings to survived for a long time.
Some my sketches on this topic.
