British carpenters, it is difficult to understand that in more than 600 years, the Forbidden City has experienced more than 200 extremely destructive earthquakes, why Chinese never worried about it being collapsed?
Including the earthquake that leveled Tangshan, the epicenter was only 150 kilometers away from the Forbidden City, and many ancient buildings in downtown Beijing were damaged, but the Forbidden City remained unchanged. How many ancient people's painstaking efforts and wisdom have been gathered in ancient buildings like the Forbidden City, and what black technology is hidden that we cannot answer in modern times?
Ancient Chinese buildings that can withstand a 10-magnitude earthquake
In order to figure out these problems, in 2017, British carpenters copied several models of the same structure as the Forbidden City building in a 1:5 ratio, and then put it on a platform that simulated earthquakes and began to test how many magnitudes it could withstand.
The staff first adjusted the earthquake scale to 4.5, such an earthquake will make people feel the obvious vibration, enough to cause some simple building walls to crack or even collapse directly. The Forbidden City model on the top of the overall shaking amplitude is very large, looking shaky, but in the 30 seconds of test time, it has never collapsed.
Judging from the strong shaking of the Forbidden City model, foreign experts believe that it will completely fall apart before it can withstand a magnitude 6 earthquake, while the Chinese experts present look at each other and smile and do not speak.
When the on-site staff actually adjusted the magnitude to magnitude 6, foreign experts were surprised to find that the model was shaking almost the same as just now, but there was still no sign of collapse.
Subsequently, the magnitude was adjusted to 7.5, which is already the amplitude that can only be expressed by many large earthquakes. Only to see that the model of the Forbidden City shook violently, and the internal wall surface also collapsed, but the entire wooden structure still did not collapse, and there was no disconnection at the junction of the main beam and the column.
The magnitude is still increasing, this time directly rising to 9.5, which is the strongest earthquake in human history, but the results are the same as before. Unwilling foreign experts adjusted the magnitude to the maximum magnitude of 10, and after 30 seconds the whole scene was silent, and the entire model still stood on the seismic platform intact.
The foreign experts were finally convinced, but they were too confused, how could such a weak-looking wooden frame, without a single screw, withstand a magnitude 10 earthquake? Chinese experts stepped forward and pointed out to foreign experts the red markings under the pillars of the Forbidden City model. It turns out that compared with before the earthquake, the building has moved a few centimeters in its entirety.
The Forbidden City has no foundations?
Architects all over the world are wondering why ancient Chinese architecture is so earthquake resistant. In fact, Chinese architects do not agree with the term "earthquake resistance", they are more inclined to believe that ancient buildings rely on their own unique structure to absorb and dissolve the impact of earthquakes, which is quite the meaning of the Taoist Taijiquan "four or two strokes of a thousand pounds". So how exactly is this done?
Let's first look at how modern architecture builds houses. Modern people must first lay the foundation, insert the pillars into the foundation, then repair the load-bearing wall, and finally cap it. Such a house has a disadvantage, that is, it is too "straight", the ancients said "too rigid and easy to fold", this repair house is the same.
The columns of modern buildings are always inserted in the ground, which seems to be very stable and can withstand many earthquakes, in fact, when the earthquake occurs, more than 95% of the buildings collapse from top to bottom. Your pillar may be able to withstand the impact of an earthquake, but when the upper house begins to shake from side to side, the stiff column will break in an instant, causing the entire house to collapse.
The biggest difference of ancient architecture is that the columns are not directly inserted into the ground, and its structure is more complex. Taking the Taihe Hall of the Forbidden City as an example, below its columns are the pillar foundations (础磉 disk), which is the disk-like structure on the ground; There are also piers made of stone bricks under the pillar foundations.
It looks like the column is inserted into the ground, but in fact it can move within the range of the pier without breaking the column.
Many people may say, then isn't this house like the building blocks on the ground, without a foundation? In the past, some people did say that the building of the Forbidden City had no foundation, and even questioned whether the ancient Chinese did not understand architecture. But have you ever wondered how a group of houses without foundations have resisted countless earthquakes for more than 600 years?
Therefore, the Forbidden City has a foundation, not only there is, but the ancients attached the greatest importance to the construction of the foundation. In the classical architectural work "Constructing the French Style", there are detailed records on where to repair the foundation, how long and wide it is repaired, and even the use of stone bricks in that place, the use of wood in a place, what actions to use, and how many squares of earth are written very finely. It can be said that the foundation of the Forbidden City, the complexity of the structure, and the exquisiteness of the materials used are unique.
Foundation structure of the Forbidden City
Tenons are the soul of ancient architecture
Of course, it is not difficult to build this foundation, the most difficult thing is to repair the roof, and when it comes to the roof of the ancient building, it is inseparable from the tenon structure, and it is not too much to say that it is the soul of the ancient building.
Tenon structure by the mortise and tenon two parts, can be nested and fixed to increase the stability of the building, just a window has 500-1000 tenons connected, and in order to build a large building roof, it is estimated that there are no tens of thousands of small parts at all.
Mortise
So why did the ancients build houses so complicated? Isn't it possible to go straight like modern reinforced concrete? It really doesn't work, let's look at the role of the mortise and tenon structure to understand.
Tens of thousands of mortise and mortise roofs, when encountering an earthquake, each part has the effect of absorbing the seismic impact force, and then continuously transmit this force down, which plays a role in unloading the force in the process of transmission. Therefore, we can see that at the time of the earthquake, even if the pillar has shaken very badly, the roof is still not moving like a mountain.
At the same time, because the tenon structure has a very small gap when it is inlaid, it is not as rigid as a piece of reinforced concrete, but has a certain flexibility and elasticity, allowing the material to produce a certain deformation, so it is not easy to break and collapse.
In 1973, a Chinese archaeological team discovered this magical mortise and mortise structure in the Hemudu cultural site in Zhejiang Province, which was detected to be 7,000 years old. In fact, the tenon and tenon structure is not the most unique invention of ancient Chinese architecture, and similar tenon and tenon structures have been found in the archaeology of the original ruins in Germany, and it also originated 7,000 years ago. Therefore, China may not be the originator of the tenon structure.
Ancient architecture and the core technology - bucket arch
However, it is worth noting that in the Warring States period, the mortise and mortise structure was further developed, and the bucket arch structure was derived, which can really be regarded as the essence of ancient Chinese architecture. Not only because the bucket arch structure has not been found in other civilizations in the world, but also because it makes ancient Chinese architecture more practical and beautiful.
Bucket arches are mainly used at the intersection of building columns, beams and roofs, and the main role is to enhance the stability of the house. From the Warring States to the Tang Dynasty to the later Ming and Qing Dynasties, successive generations of architects have strengthened the role of the dou arch, but the Japanese have lost the soul of the dou arch when imitating the Tang Dynasty architecture, so many people will think that the ancient Japanese architecture looks very awkward.
In fact, the structure of the bucket arch is not only used to build houses, but also plays a crucial role in the construction of bridges.
In January 1975, a batch of 429-ton mechanical components was urgently needed to be transported to Yanshan Petrochemical Company, but because the cargo was so heavy, experts could not guarantee that several new bridges on the Yongding River would be able to complete the task.
- Experts say it seems that this task can only be handed over to the ancient bridge, without reinforcement, it is no problem.
Do you know that this is an ancient bridge built 800 years ago, is it really more reliable than the new bridge at that time?
When the 429 tons of equipment was opened on the bridge, everyone sweated, because the bridge arch was sinking, the maximum sinking amount reached 0.52 mm, and watched as the ancient bridge would sink into the river with the equipment. Who knows that after 20 minutes, the equipment will pass safely and the ancient bridge will be safe and sound. The original arch bridge sank mainly because the bucket arch of the bridge had a certain toughness, and although it underwent minor deformation, it did not collapse as a result. And this magical ancient bridge is the famous Lugou Bridge.
Lugou Bridge
The inheritance of ancient architecture
Looking back today, from this classical architecture of "rigidity and softness", we can also feel the unique wisdom of Taoism. However, modern people who have mastered countless high-tech technologies can no longer reproduce this ancient architecture, and perhaps in the "technology" of the ancients, there are some mysteries that are difficult to solve in modern physics and mathematics. And we only learned a little bit from the ancient architecture.
Tengwang Pavilion
Sometimes, modern people not only have difficulty copying classical buildings, but even destroying them. In Ying County, Shanxi, there is the world's tallest wooden pagoda certified by the Guinness Book of World Records, which is the Shakya Pagoda, also known as the Yingxian Wooden Pagoda. It was built in 1056 and is known as the "Three Great Wonder Towers of the World" along with the Leaning Tower of Pisa in Italy and the Eiffel Tower in Paris.
Ying County Wooden Tower
This ancient wooden pagoda has stood after nearly a thousand years of wind and sun and more than 10 major earthquakes. However, in the chaos of the war in 1926, it was attacked by the artillery fire of Feng Yuxiang's army, and more than 200 rounds of bullets did not collapse. The magic is this: even in the war years, the cannonballs that hit the tower and ignite the fire will be extinguished in an instant... (From Xinmin Evening News)
Despite this, the recent situation of the wooden tower is not optimistic, it is said that the Leaning Tower of Pisa is only 3.99 degrees, while the second floor of the Yingxian Wooden Tower is tilted by 15 degrees, which is shocking!
Today, we can automate the production of mortise parts with a steady stream of machines, but we can no longer build a building like the Yingxian Wooden Pagoda.