Wednesday, April 15, 2015

Structure of Great East Hall

By Haoyang Li


The structure of Great East Hall is following the technology from old time. The Nanchan Temple is the oldest extant building right now, its structure is as same as the Foguang Temple. All by wood and Dougong. But the size is smaller than Foguang Temple. According to the background, the reason why Nanchan temple was survived from Wuzong banned the Buddhist is too small. So we can see the Building at Tang Dynasty is almost the same. (http://en.wikipedia.org/wiki/Nanchan_Temple_(Wutai)) Base on the grid to put the wood columns and used the Dougong to connect the column and the beam system. Then put the roof system on the top of it. Horizontal beams and vertical beams compose the beam system. The cross of the two beams is connecting by Dougong. The roof system has different layers. The middle is higher than the two sides. (Figure 6).

The main and most important element of structure is Dougong. Without Dougong there will be no Chinese wood structure. The term, Dougong, means simply block (dou) and “arm” (gong). The tiers of “arms”, when extending into the interior of the building, receive the ends of the principal beams, while the other half of the “arms”, extending outward, receive the overhanging eaves of the roof. The Dougong was originally conceived as a structure element, but its decorative potentiality was soon discovered and exploited to the utmost degree. (Liang, 2011, P8)  The length of Gong is different. Form the bottom to top, the length of Gong will become bigger and bigger. The roof is on the top of Dougong, and the load will go from the longest and top Gong through the Dou to the second smaller Gong. And go on to the bottom Dou. (Figure 7) Under the bottom Dou is the main column. The main column is straight to the ground. Through this system, Dougong make the load to the ground. The Dougong and the column together make the one element to support. Lots of this element together will support the whole roof.
The different part of Dougong is different way to put Dou and Gong together. Just like the normal place under the roof and the corner part. For Great East Hall, there has seven ways to make Dougong. From the Wai Cao, there are three ways. From the Nei Cao, there are four ways. (Liang, 2001) These seven ways different from each other, but the big difference is among the exterior one, inside one and the corner one.
The exterior one (Figure 8) is the most beautiful one look from the section plan. And this Dougong more likes outgoing character. The bottom part of it is as same as the other Dougong, just put Dou and Gong layer-by-layer together. But the top part is different and amazing thing. There are two oblique pillars expose to the outside and from inside connect to the Gong. And usually color the pillar with bright color to contrast with the roof. The oblique pillars have the sharp corner at the on side. This sharp corner make the pillar and roof together show people the beauty of Dougong. 

The interior one (Figure 9) is more like stable character. It repeats the same format. The different is the length. Unlike the exterior one. The interior one is face to the interior space. So it needs to be friendly to the people inside. If exchange the format of exterior and interior. Make the sharp corner face to the people. The feeling to the interior people will be a strong stress. So the interior one is more soft and “calm” than exterior one. But put exterior and interior together will make them more balance and become wonderful.
The corner Dougong (Figure 10) is complex. It connects the two sides. Extend and intersect the two sides. Follow the number of layer of the exterior Dougong, add the same number of oblique pillar. This also fit to the corner style of roof.
Unlike some building nowadays, they just use some dispensable part to decoration the wall. Dougong have the function to be supporting elements, and also have the beauty affect. On the top part of Dougong, also is the part under the roof, coming out to the outside. With the color and style of the roof, Dougong also have its own style. The Dougong fill the space between the roofs and wall perfectly.  If changed the style of Dougong, the temple will not be so beautiful like now. If removed the Dougong, the temple will collapse. That is why Dougong has so many magical mean to the Chinese Architects, and maybe to the world-wild.



Source
Figure 1: Unknown (Photographer). (Unknown) The construction of Great East Hall. (Print Photo). Retrieved from Fu, Collected Works of Fu Xinian on Architecture History, 1998, P237
Figure 2: Unknown (Photographer). (Unknown) Dougong. (Web Photo). Retrieved from: http://www.china001.com/show_hdr.php?dname=KLDNB41&xpos=9
Figure 3: Unknown (Photographer). (Unknown) Section of Exterior Dougong. (Print Photo).  Retrieved from Liang, Liang Si Cheng Quan Ji (Vol. 10), 2011, P386

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