Walking into the Forbidden City
- The pillars that supports three thousand gold
Writer: Yang Yuhao
Forbidden City Sunset
Image taken from Imgur: The magic of the Internet
“墙倒房不塌” (Even if the walls fall, the house will still stand), has been widely used to describe traditional Chinese architecture. Many would think that the “Free plan” in architecture is popularized by Le Corbusier in the 1900s, however, before the dawn of the 20th century, the same principle has been widely employed in traditional Chinese structures for centuries. Held up by massive wooden pillars, palaces in the forbidden city are all constructed with meticulous engineering and design strategies to ensure that these buildings can withstand the test of time. In this instalment of “Walking into the Forbidden City” we will continue to unravel the secrets of the palace by examining some of the design wisdom embedded in ancient Chinese architecture.
Temple of Heaven
Image taken from 11 Temple of Heaven - Temple of Heaven - Wikipedia
Comparing all palaces in the forbidden city, one would notice the marvellous similarity in design and structure of most of the structures within the complex. Following the traditional Chinese philosophy’s emphasis on unity, uniformity and stability, traditional Chinese building are mainly made up of three components, namely the roof, supporting beams and the base. A closer examination of some of the more notable traditional infrastructures (such as the Temple of Heaven (天坛)) reveals meticulous details and ornamentations on the roof, beams and on the staircase leading up to the temple, denoting the importance of these components to a building.
The foundation of a building is heavily emphasized in traditional Chinese architecture. Seen as the origin of the building, the foundations of wooden structures commonly consist of nailing large pillars into the earth to form the central supporting system of the entire building. Differing from that, the palaces in the forbidden city adopted a different system. Instead of sinking the supporting beams into the earth, the beams are rested on foundation stones. This “floating foundation” system seems less sturdy, however, plays an important role in the anti-seismic property of the complex. Comparing the two systems, the former seems sturdier due to its rigidity. On the contrary, this very rigidity of the support system is very susceptible to breaking in the event of an earthquake. In contrast, the less rigid “floating foundation” system allows for plenty of wiggle space for the supporting pillars, contributing to the more effective dissipation of energy from these load bearers, therefore making the overall structure significantly more earthquake-proof. Additionally, following the principle of “石为上，砖为下” (stone on top and brick below), the foundation that the pillars rest on is made up of layers of bricks topped with marble slabs. This structure is not only cosmetically pleasing but also allows the foundation to be laid flat, echoing the Chinese philosophy of 四平八稳 (flat on 4 sides contributes to the stability in all 8 directions).
Floating Foundation
Image taken from 15-The concept of floating foundations (left) and the Forbidden City in... | Download Scientific Diagram (researchgate.net)
Moving up the building, stripping away walls of the palaces reveals the load-bearing beams supporting the entire structure. Being the middle portion of the construction, the pillars of these buildings are usually made out of a single trunk of a tree. The heavy weight of the dugong roof system requires sturdy supports, hence these pillars are also given the name 立木顶千金 (The pillars that supports three thousand gold). The unique dugong system also contributes significantly to the anti-seismic ratings of the palace buildings. Made out of perfectly fitting slots between wooden joints, the construction of the palace buildings usually does require any glue or nails. The wooden joins, though snuggly fitted together, have a certain degree of flexibility that allows them to deform and dissipate energy in the event of an earthquake. Working together with the “floating foundation” that it sits on, the entire structure can achieve an anti-seismic rating of more than 9, a remarkable feat that is hard to achieve even with the technology that we have today.
Dugong structure
Image taken from (a) Dougong brackets from China (The Sakyamuni Pagoda of Fogong Temple,... | Download Scientific Diagram (researchgate.net)
The brick-red walls of the forbidden city stood the test of time, still guarding this sacred fortress 600 years after its construction. In the next TASpeak, we will continue to look at each of the 12 central palaces, to unpack the architectural marvels of the ancient times. (To be continued …)