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Dougong (Chinese: 斗拱;pinyin:dǒugǒng;lit. 'cap [and] block') is a structural element of interlocking woodenbrackets, important in traditionalChinese architecture for both its structural capacities and cultural implications.
The use ofdougong first appeared in buildings of the late centuries BCE, with its earliest renditions emerging during theWestern Zhou Dynasty,[1] evolving over the centuries into a structural network which joined pillars and columns to the frame of the roof.Dougong were widely used by the ancient Chinese during theSpring and Autumn period (770–476 BCE) and developed into a complex set of interlocking parts by its peak in theTang andSong periods. The pieces are fitted together byjoinery alone withoutglue orfasteners, requiring precise carpentry.
After the Song dynasty, brackets and bracket sets used in palatial structures and important religious buildings became more ornamental than structural, moving away from the description of traditionaldougong.
Dougong is part of the network of wooden supports essential to the timber-frame structure of traditional Chinese building.Dougong serve as a connection between the vertical columns and horizontal beams of a structure, capturing the weight of a larger surface area of each beam and transferring it vertically through the column.[2] It is characterized by layers of interlocking bracket sets, formed by placing a large wooden block (dou) on a column to provide a base for the bow-shaped brackets (gong) which in turn support either the horizontal structural beam or another bracket above. The wooden joinery is one of the earliest examples of modernmortise and tenon joints,[3][4] using precisely cut notches and grooves to allow for a tight fit.
This process can be repeated many times, and rise many stories, each layer ofdougong joinery providing a broader, and more stable surface area for the beam. Adding multiple sets of interlocking brackets reduces the amount of strain on the horizontal beams, creates elasticity, and allows structures to withstand damage from earthquakes.
During the earlyTang andSong dynasties (618-1297),dougong was used primarily as a weight-bearing structural element.[5] Walls, in much of traditional Chinese Architecture of the time, functioned to delineate spaces within the structure rather than to support its weight. Since often the walls in these structures were not load-bearing(curtain walls), made oflatticework,mud, or other delicate material, the integrity of external load bearing features, such as thedougong, were critical to the structure's integrity.
Asdougong developed throughout Chinese dynasties, so too did its ornamentation and cultural importance.
From its initial emergence, joinery systems resemblingdougong displayed neither ornamentation nor fixed norms or systems in their construction.[1] Over the next several centuries, and with the increasing importance ofBuddhism, more emphasis was placed on decorative elements in wooden joinery, and these initial systems began to take on a more consistent form.It wasn't until the lateSong Dynasty, a time of economic prosperity in much of China, thatdougong began to take on its rich decorative characteristics.[1] During theMing dynasty, (1368–1644) innovation brought about the invention of new wooden components that aideddougong in supporting the roof. This alloweddougong to add a decorative element to buildings, exemplifying the traditional Chinese integration of artistry and function. Bracket sets became smaller and more numerous, and brackets could be hung under eaves, giving the appearance of graceful baskets of flowers while continuing to support the roof.[6] TheBao'en Temple inSichuan is a good example of the Ming style. It has forty-eight types and 2,200 sets ofdougong to support and ornament it. It is a well-preserved fifteenth century monastery complex located in northwesternSichuan province,China. It was built by Wang Xi, a local chieftain, between 1440 and 1446 duringEmperor Yingzong's reign (1427–64).[7]
Throughout this development,dougong came to represent cultural hierarchy and identity. For a time, the use ofdougong was banned from public use, and as a result became a representation of the upper & ruling classes.[1] Some of the most studieddougong are found in theForbidden City, representing the height of imperial power.
Modern research has increasingly showndougong's importance in resisting the destructive capabilities of earthquakes.
Each element of thedougong system is fastened without the use of static fasteners such as bolts, pins, screws, or nails. Each bracket in thedougong system is held together by the friction fit of each joint and the compressive weight of the vertical load. Each column, in addition, is supported without the use of fasteners often by cornerstones[8] or other stone mounting features.
The capacity for seismic resistance indougong joints and systems comes primarily from their ability to dissipate energy between column and beam through friction, compression deflection, rotary deformation,[8] and extrusion.[1] In essence, the dynamic nature ofdougong's construction dissipates seismic energy as it travels through the joints, offering a layer of protection for structures that employ it.
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