What is the role of the arch in traditional Chinese architecture

Traditional Chinese wooden frame system building unique components. Used for the top of the columns, forehead square and eaves or between the frames, the Song "building method" in the store called, the Ministry of work in the Qing Dynasty, "engineering practice" called the bucket section, commonly known as the arch of the bucket. Bucket is a bucket-shaped wooden cushion, arch is a bow-shaped short wood. The arch is set up on the bucket, picking outward, and the arch end of the bucket, so that layer by layer, vertical and horizontal superposition, forming the upper large and lower small bracket. The arch was initially placed in isolation on the column or pick the outer end of the beam, respectively, to transfer the load of the beam in the column and support the weight of the eaves to increase the depth of the role of the eaves. In the Tang and Song dynasties, it was combined with the beams and square beams as a whole, and in addition to the above functions, it also became part of the structural layer to maintain the integrity of the wooden frame. After the Ming and Qing Dynasties, the structural role of the arch metamorphosis, became in the column network and the roof frame between the main decorative components.