Dougong: These Ancient Chinese Brackets Make Buildings Earthquake-Proof
Developing earthquake proof building technology occupies a lot of time for architects and engineers. But one country already solved the puzzle of how to get buildings to survive the devastating natural disaster. In fact, they did 2,500 years ago. Ancient Chinese timber building systems have a bracket system called dougong that survives modern day shake tests.
[Image Source: Li Jie/Wikimedia Commons]
Timber framing design science developed in both Europe and China over the last few centuries. One marked difference between the two schools of thought is the need for the Chinese design to be able to withstand extreme seismic activity. Thus the dougong system was invented. The secret to dougong is to utilize a design that could not be shaken apart, not shattered when under stress.
[Image Source: Gisling/Wikimedia Commons]
The system is a series of interlocking beams cut to precise measurements, that when compressed under the weight of the buildings' heavy timber roofs, are strong enough to withstand earthquakes. By using a large number of pieces in the design, the weight is shared and so individual elements are not prone to splitting or cracking.
[Image Source: 663highland/Wikimedia Commons]
What shocks most European architects is that the system isn't sunk into the ground with a foundation or footing, rather it floats, sitting lighting on the ground. Check out this video to see just how complicated the system is.
Dougong was used on many buildings during the Spring and Autumn period which was between 770- 476BC to create buildings from temples to palaces. The pieces are fitted together without using glue or any fasteners and require incredible skill and precision to fabricate each timber piece.
[Image Source: Haier7917/Wikimedia Commons]
Contemporary earthquake proof architecture relies on high tensile cross bracing as well as isolated foundations to meet international standards.
Earthquakes in China
Earthquakes are experienced in many parts of the world, but China has some of the worst. In a list of the world’s 10 deadliest earthquakes. China takes out the top two positions. China is susceptible to earthquakes due to the structure and position of the globe's tectonic plates. The most recent massive earthquake occurred in 2008 in the Sichuan province. Over 69,000 people lost their lives in the earthquake and more than 300,000 were injured. Poor building design and shoddy construction work were blamed for the high death rate. Since the earthquake, massive changes in regulations have been introduced to ensure buildings are rebuilt to be able to withstand earthquakes. The Chinese building code is now to an international standard.
However, enforcement of the laws is a challenge. China is creating new cities and buildings at an astounding rate and this speed, as well as the use of low-quality building materials, means not all buildings are meeting the expected standards. China's common place government corruption also fuels the shortcuts in the buildings which can have deadly consequences.
Kit Miyamoto, the president and CEO of the earthquake research firm Miyamoto International says "You need more than just good building codes. You also need good engineers to implement the code, and good contractors to implement the engineers' vision."