CHINESE ROOFS SERIES

These curves were sometimes further exaggerated for aesthetic effect. It increases the amount of light for the same rain protection it helps to hold the shingles together and it optimizes the flow of water, being more steeply pitched at the start of the slope where more gravity is needed and more shallowly pitched where the increased accumulation and momentum of the water helps the roof to shed water. The classic upturned curve of the Chinese roof is due to several considerations. Traditional Chinese Roofs Roof ShapesД«ecause Chinese timber frames create independently stepped supports for the roof, and their rafters are laid only across a single bay (jian) at a time rather than directly from ridge to eave as in Western construction, this allows for variation in the slope of the roof. The system allows for wide eaves to protect against rain and damp, and it allows multi-storey construction, resulting in some of the tallest wooden structures in the world, some of which, like the Sakyamuni Pagoda, are still standing nearly a millenium later. Because the connections are made with wood joinery and dowelling, they are able to withstand the dynamic loads from storms and earthquakes without damage to the structure. Because it does not rely on load-bearing walls, and because it allows connections at many different angles, it allows for great flexibility in programming and has been able to accommodate architectural changes across a vast span of time and geographic climate. The earliest references to dou-gong bracketing date from the Zhou Dynasty (1100-256 BCE), and it was in use in China through the 19th century when modern Western technology was introduced. Owing to the strength and flexibility of the dou-gong system, it has persisted across millenia. Colorful lacquer and paintings embellished palaces while protecting the wood from water. Over time these brackets and their joinery became increasingly complicated and increasingly decorated, signifying the wealth and importance of the building and its owner. Dou-gong bracketing allowed the connection of multiple beams, potentially at varying angles, to the same column. It reduced spans, increased the strength of these moment connections, and absorbed shock from wind and seismic activity. Dou-gong bracketing used wooden bearing blocks (dou) and bow-shaped brackets (gong) to distribute the load of the roof across beams, and to connect beams to columns. Since the walls in such construction were not load-bearing, this led to the need for sophisticated joinery techniques to support the roof, and hence the development of the dou-gong bracketing system.

CHINESE ROOFS SERIES

Two main forms of framing were developed: the tailiang system, in which the roof was supported by a stacked series of cross-beams raised upon each other by struts, and the chuandou system, in which the roof is supported by increasingly taller columns stabilized by tie-beams.

While the combination of timber framing and rammed earth walls were common in the Han dynasty (200-25AD) and earlier, later construction tended to use pure timber structures. Traditional Chinese Timber Frames and Dou-Gong BracketingД¬hina has a long history of heavy timber frame construction, from prehistoric times onward. MARCH-631 History 1: Ancient to Medieval / Ronaldo Deluna, Elika Etemad, Juan Rosario, Kimberly Tanz Chinese Architecture: Roofs and Bracketing

Chinese roofs