Now when it comes to Luding Bridge, many people's first impression is the thrilling battle that happened 90 years ago.
In May 1935, after the Red Army forcibly crossed the Dadu River, in the face of the enemy's heavy fortification on the opposite side of the bridge, and the difficult conditions that the bridge deck was demolished to almost iron, 22 Red Army warriors successfully captured the Luding Bridge with extraordinary courage, making Chiang Kai-shek's vain attempt to make the Red Army the "second Shi Dakai" plot completely bankrupt.
Since then, Luding Bridge has become one of the best portrayals of the great victory of the Red Army during the Long March.
Before the Red Army soldiers flew to capture the Luding Bridge, in fact, this chain bridge had been standing on the Dadu River for 300 years, and it was the Kangxi Emperor of the Qing Dynasty who contributed to the completion of this bridge.
So the question arises, the 13 iron chains on this iron chain bridge, there are more than 10,000 iron rings that constitute the iron cable, and the total weight even reaches more than 40 tons, and in the Qing Dynasty, which did not have modern machinery and equipment, how did it be built on the turbulent Dadu River?
1. A bridge that Kangxi had high hopes for
The reason why Kangxi wanted to build this bridge was due to two needs.
In the 39th year of the Kangxi reign (1700 AD), there was a rebellion in the Dajian Furnace Hall (i.e., Kangding) on the border between Sichuan and Tibet.
When the news reached the capital, Kangxi naturally would not sit idly by, and with his order, the Qing army arrived at the Arrow Furnace Hall in the first month of the following year and began to encircle and suppress the rebellion.
After all, it was a local force, and it would definitely not be able to compete with the central court, so it took less than half a year for the rebellion to be put down.
After the war, in order to deter Gushi Khan of the Heshute Mongol Department in Tibet, and to prepare for the recovery of Tibet in the future, Kangxi set up a yamen agency here to stabilize the local situation.
With the arrival of the Yamen, the area also returned to its former prosperity, due to its location on a choke point. Whether it is Tibetans entering Sichuan or Han people entering Tibet, they will pass through here, and over time, the local government will find a very serious problem.
What is the problem? It is very inconvenient to communicate with Tibetan areas.
In addition, the Qing court would often send troops into Tibet to deter the Mongol tribe of Heshute, but because of the inconvenient transportation, the army was also very troublesome in entering and exiting.
Some people will say that if the traffic is inconvenient, shouldn't it be enough to build roads and bridges? Everyone understands the truth, but in the local area, building bridges is a very difficult thing to do.
Why? Quite simply, there is a famous Dadu River.
Dadu River, also known as Moshui and Dadu Water in ancient times, is one of the largest tributaries of the Minjiang River, a tributary of the Yangtze River, and its birthplace is the southern foot of Guoluo Mountain in Qinghai, which flows through Jinchuan and Danba all the way down to the south, and then turns to the Arrow Furnace Hall, and finally turns to the east and flows into the Minjiang River in Leshan.
It was from Danba that the name of the river became Dadu.
And we all know that in the Danba area, the terrain is known for its danger, so with the blessing of the topography, the water flow of the Dadu River with a width of hundreds of meters is very turbulent, according to the statistics observed by the local hydrological station, the annual average flow of the Dadu River has reached 1510 cubic meters per second, and the annual average runoff is as high as 47.3 billion cubic meters.
The average annual runoff alone is ten times that of the Yellow River, which shows that the Dadu River is indeed quite turbulent.
So in this case, it is undoubtedly difficult to build a bridge on the river, which is why before the Qing Dynasty, there was no bridge on the Dadu River, not because I didn't want to build it, but because it was really difficult to build.
So some people will ask, how can the locals cross the river without a bridge? It's very simple, sheepskin rafts or boats, and there are also rattans at your disposal, and this is what the locals have always used to cross the river.
However, this kind of river crossing tool, it is good to say that it is good to catch up with the wind and waves, but if you catch up with the wind and waves, it will be troublesome.
Therefore, for a long time, the local habit is to take advantage of the calm flow of the river to cross the river, but even so, accidents often occur, as long as one is not careful, even people and boats will be washed away without a trace.
Therefore, considering the needs of army mobilization, as well as the needs of the people's daily travel and trade, it became a top priority to build a bridge over the Dadu River that could cross the river.
After being reported by local officials, the Kangxi Emperor also believed that a bridge should indeed be built, so he agreed to the proposal with a stroke of his pen.
In the forty-fourth year of Kangxi (1706 AD), the holy decree of building a bridge over the Dadu River was delivered to the local area, but after the officials received the decree, they did not immediately start to act, but fell into a state of confusion.
Since the emperor has approved it, what is there to be at a loss? It turns out that the officials in charge of building the bridge have encountered several major problems, and if these problems are not solved, then the bridge will not be built.
What is the problem? Is it a lack of money? Of course not, the money has already been allocated by the imperial court, and what they lack is technology.
Second, three technical problems
As we all know, there was no modern advanced technology and various equipment in ancient times, so it was impossible to build bridges like modern times.
This tenet is called adapting measures to local conditions.
The meaning of adapting measures to local conditions is easy to understand, which is to decide what type of bridge to build according to the topography of both sides of the bank where the bridge is to be built.
Generally speaking, the type of bridge is either a beam bridge, that is, a bridge with beams as the main load-bearing, which is characterized by sturdiness and durability, maintenance and labor-saving, and it is also the earliest type of bridge in the mainland.
A single-plank bridge that connects the two sides of the river with a long log is actually a type of beam bridge.
But the problem is that, according to the technical conditions at that time, it was almost impossible to build a girder bridge on the Dadu River, which spanned hundreds of meters, and even in modern times, there are few examples of building girder bridges on the river surface of this width.
The other is the arch bridge, but this kind of arch bridge with a unique shape is generally used to build in small terrain, so it will not work.
And the last one, is the rope bridge, that is, the iron chain bridge, this kind of bridge is a cable or chain cable as the main load-bearing component, the material saving, light weight is the biggest feature, especially suitable for the construction of large span valleys, rivers.
Therefore, the officials finally decided to build a chain bridge over the Dadu River.
Once the plan was decided, the next step was to figure out how to build the chain bridge, and it was here that officials encountered technical difficulties.
After summing up, there are three questions.
First of all, it is the iron cable used in the construction of the chain bridge, the iron cable is naturally connected by iron rings, after calculation, if the bridge wants to meet the needs of the army and daily river crossing, as well as to ensure stability, then it needs thirteen iron cables.
Of the thirteen iron cables, four on the left and right sides are used as handrails, and the remaining nine are bridge decks.
However, the width of the Dadu River is hundreds of meters, so the length of each iron is naturally at this number, and in order to achieve this length, then each iron cable needs about more than 900 iron rings, and thirteen iron rings are counted to reach more than 10,000 iron rings.
The scheme is a good design, but the question is, where to get so many hoops?
Of course, this problem is not too difficult to solve, and an official mentioned at the time that Yingjing County (now Ya'an, Sichuan), hundreds of miles away from the Dadu River, is a place where iron is produced, where iron resources are abundant, and there are supporting smelting workshops, so the iron rings can be smelted and forged there according to the requirements before being transported here.
So according to this proposal, the work was quickly prepared, and in order to ensure the quality of the iron rings, the officials also specifically required that the name of the forging craftsman must be engraved on each forged iron ring, and once a certain iron ring was found to have quality problems, then the craftsman would be directly questioned.
The first problem was solved, and the second problem hurt the officials a lot.
When the batches of iron rings were transported to the Dadu River, the workers realized that how to get the iron cables made of iron rings to the opposite bank was a big problem, after all, these iron cables in tons were too heavy.
At that time, some people also tried to take one end of the iron rope and then take a sheepskin raft or boat, but the current was really turbulent and still moved laterally, so several attempts were unsuccessful, and several craftsmen were swept away by the flood.
In the end, though, the rope was transported to the other side of the river, so how did the workers do it?
There is a local legend about this matter, saying that in order to be able to send the iron chain to the other side, there was a young Hercules who tied the iron rope around his waist, and then drove the boat with divine power, and sent more than a dozen iron ropes one by one, and after the delivery, the strong man also died on the spot due to exhaustion.
Of course, this is just a legend, but the real situation is that the working people have exerted their wisdom.
It turned out that the workers were inspired by the local people's daily behavior of crossing the river with rattan ropes, they first made coarse bamboos at both ends of the river, then connected them with rattan ropes in the middle, and finally put more than 10 short bamboo tubes on the rattan ropes, so that a simple tool for crossing the river was made.
When everything is ready, the people on the other side of the river tie the chains to the short bamboo tubes, and then the people on the other side pull the ropes, and so on, and the chains can be passed over.
And after the chains are in place, there is one last problem left, which is to secure the 13 heavy chains.
This problem is not less difficult than the first two questions, after all, each iron chain is made of sufficient materials, and it is also quite weighty, and in order to ensure the durability of the bridge, the iron chain must be fixed in place, otherwise the iron chain can not withstand the pulling force for a long time, and then it falls off, which is not only the entire bridge is destroyed, but also causes the people walking on the bridge to fall into the river.
Therefore, the problem was not to be sloppy in the slightest, and in the end, the workers fixed the iron ropes in the same way that the bunkers were built at that time.
The specific method is to build a huge bridgehead on both sides of the bridge, and then dig a deep well below the bridgehead after the bridgehead is built, and finally start from the bottom of the deep well, and pave the layers of dragon piles that are crisscrossed horizontally and vertically.
According to historical records, just casting these dragon piles cost more than 40,000 catties of pig iron, which was converted to modern times according to the unit of measurement at that time, that is, about 20 tons.
With such a willingness to use materials, the cast dragon pile is naturally extremely strong.
After the dragon pile was cast, the workers began to connect and fix the thirteen iron chains, and on the nine chains at the bottom, a wooden bridge deck was laid to facilitate the walking of people and horses, and the four iron chains on both sides were connected by small iron rings in the middle to prevent swinging back and forth.
Eventually, the workers built bridgeheads on the other side of the river, and a 103.67-meter-long, 3-meter-wide chain bridge connecting the two banks of the Dadu River was officially completed.
3. A bridge to witness history
In April of the forty-fifth year of Kangxi (1706 AD), the iron chain bridge on the Dadu River was officially completed, and the Kangxi Emperor who learned of this was very happy, and personally wrote the three big characters of "Luding Bridge".
This name, in fact, has a deep meaning, Kangxi is to take the meaning of "Lushui" and "stability" and named the bridge, at the same time at the head of the bridge, but also three words set up a monument, in addition to the Kangxi handwriting "Luding Bridge" three words, there is also a sentence for "unification of mountains and rivers", Kangxi's meaning, is to hope that the Tibetan area can be pacified as soon as possible, to complete the unification of mountains and rivers.
As a result, the name has accompanied the bridge through hundreds of years.
In these hundreds of years, Luding Bridge has witnessed too many changes in history, and it is no exaggeration to say that Luding Bridge is a bridge that carries history.
In 1863, that is, the second year of Tongzhi in the Qing Dynasty, Shi Dakai, the king of wings, led his troops here, and wanted to cross the Dadu River to escape from the pursuit of the Qing soldiers.
After that, it was the Red Army soldiers who bravely captured the Luding Bridge.
On May 29, 1935, under the leadership of Wang Kaixiang and Yang Chengwu, the Red Fourth Regiment marched 240 miles and reached the west bank of Luding Bridge in only one day, and quickly and decisively annihilated the enemy here, preparing to attack the other side of the river.
In order to avoid being broken through by the Red Army, Liu Wenhui ordered to defend to the death on the one hand, and on the other hand, he sent people to remove all the wooden planks on the bridge, and also built fortifications at the bridgehead, and used heavy machine guns, mortars and other weapons to continuously strafe the bridge deck.
Its purpose was to prevent the Red Army from passing through the Luding Bridge.
In the face of difficulties and dangers and a rain of bullets, the 22nd warriors of the Red Army fought a fierce battle to seize the bridge with extraordinary courage, and finally succeeded in capturing the bridgehead pillbox, and the follow-up troops were able to cross the Dadu River.
At the end of the Long March, Chairman Mao looked back on the countless difficulties and obstacles he had overcome in the past year, and wrote the poem "Seven Laws: The Long March" with a stroke of his pen:
The Red Army is not afraid of difficult expeditions, and thousands of rivers and mountains are just waiting for leisure.
The five ridges are soaring and the waves are thin, and the Wumeng is majestic and walks the mud pills.
The golden sand water beats the clouds and cliffs warm, and the Dadu Bridge is cold.
I like the snow of Minshan Mountain for thousands of miles, and the three armies are happy after the end.
Among them, the chain bridge on the Dadu River has become the best witness of the Red Army overcoming difficulties and obstacles, and now, this Luding Bridge, which was built more than 300 years ago, is serving the local people while traveling, but also quietly recounting the years of hard work and hard work.