Li Chun
Li Chun
Li Chun was a bridge builder in the Sui Dynasty. Nowadays, people living in Xingtai, Hebei Province, are in the city. From the 15th year of kaihuang to the beginning of Daye (595-605), Zhaozhou Bridge (Anji bridge) was built. In the inscription on Anji bridge written by Zhang Jiazhen, the commander of the middle Tang Dynasty, it is recorded that "the stone bridge on Jiaohe River in Zhaozhou is also the trace of Li Chun, a craftsman of Sui Dynasty. It makes strange things, and people don't know what he did." Zhaozhou Bridge embodies Li Chun's sweat and hard work. Li Chun became the first bridge expert in the architectural history of China and even the world.
Social contribution
Li Chun is a famous bridge craftsman of Sui Dynasty in China. The world-famous Zhaozhou Bridge is his greatest masterpiece. It is a symbolic bridge that condenses the wisdom of the Chinese people. It creates a new situation of bridge construction in China and makes great contributions to the development of Bridge Technology in China.
The open shouldered circular arch bridge of Zhaozhou Bridge is a great creation of Chinese working people. The open shouldered circular arch bridge appeared only in the 14th century in the west, more than 600 years later than that in China. Dr. Joseph Needham, a famous British expert in the history of Chinese science and technology, once listed 26 scientific and technological achievements that spread from China to Europe and other regions from the 1st century to the 18th century in his great book the history of Chinese science and technology, the 18th of which is the arch bridge. After the completion of Zhaozhou Bridge, it has become a transportation hub in North and South China, and has a good reputation of "a thousand people go straight on a smooth road, and a courier drives all countries". Boats and boats sailing under the bridge, and people, horses and vehicles passing through the bridge greatly facilitated the transportation and people's life, and provided convenient conditions for people on both sides of Jiaohe river.
It has been more than 1300 years since the bridge was built. During this period, it has experienced the impact of more than eight earthquakes and the test of more than eight wars. It has withstood the heavy pressure of countless human and animal vehicles, and has been eroded by countless wind, frost, snow and rain. However, it is still standing on the river.
After liberation, Zhaozhou Bridge was listed as a national key cultural relic protection unit, and the relevant departments thoroughly repaired the ancient bridge to maintain its glorious historical position. Zhaozhou Bridge has become a symbol of the wisdom of the Chinese people and a place for patriotism and Historicism education. The completion of Zhaozhou Bridge has an important influence in the history of Chinese Bridge. Its large span, circular arch and open shoulder form force have created a new world for the bridge construction. After Sui Dynasty, many large arch bridges similar to Zhaozhou Bridge appeared, and more than ten have been found, such as Puji bridge in shanxigu County, Jingde bridge in Jincheng County, Yongtong bridge and Jimei bridge in Zhaoxian County, Hebei Province. Zhaozhou Bridge has become a model of bridge construction in China.
However, the outstanding technical achievements like Zhaozhou Bridge and the outstanding bridge experts like Li Chun were not valued by the feudal rulers in the feudal society, and even left few traces in the history books. We know nothing about this famous bridge except Li Chun, a craftsman of Sui Dynasty, who designed and built it. But even so, we still firmly believe that: Li Chun as a generation of bridge experts and Zhaozhou Bridge as a famous historical bridge will always be recorded in the history of the motherland and remembered by future generations.
Design innovation
The design of Zhaozhou Bridge has the following innovations in the history of Bridge Technology in China
1. Arc arch is adopted
In ancient China, most of the stone bridges were semicircular arch, which was beautiful and complete, but there were also two defects: first, the traffic was inconvenient. Semicircular arch was suitable for bridges with small span, while semicircular arch was used for bridges with large span, which would make the vault very high, resulting in steep slope and traffic It's very inconvenient for people to cross the bridge. Second, the construction is unfavorable. The scaffold used for semi-circular arch stone masonry will be very high, increasing the risk of construction. Therefore, Li Chun and the craftsmen creatively adopted the form of circular arch, which greatly reduced the height of the stone arch. The main span of Zhaozhou Bridge is 37.02m, while the arch height is only 7.25m, and the ratio of arch height and span is about 1:5. In this way, the double purposes of low deck and large span are realized. The deck transition is stable, and the vehicles and pedestrians are very convenient. Moreover, it has the advantages of saving materials and convenient construction. Of course, the thrust of circular arc arch on both ends of the bridge foundation increases correspondingly, which needs to put forward higher requirements for the construction of bridge foundation.
2. Open shoulder
. This is Li Chun's significant improvement on the spandrel. The solid shouldered arch used in the past bridge construction is changed into open shouldered arch, that is, two small arches are set at both ends of the large arch. The clear span of the small arch near the big arch foot is 3.8m, and the clear span of the other arch is 2.8m. This kind of open shoulder arch with large arch and small arch has excellent technical performance. First of all, it can increase the flood discharge capacity and reduce the impact of flood on the bridge due to the increase of water volume in flood season. Every flood season in ancient times, the water potential of He river was large, which was a test for the flood discharge capacity of the bridge. Four small arches could share part of the flood flow. According to calculation, the four small arches could increase the water passing area by about 16%, greatly reducing the impact of flood on the bridge and improving the safety of the bridge. Secondly, the open shouldered arch can save a lot of earth and stone materials and reduce the weight of the bridge body. According to the calculation, the four small arches can save 26 cubic meters of stone and reduce their own weight of 700 tons, so as to reduce the vertical pressure and horizontal thrust of the bridge body on the abutment and bridge foundation and increase the stability of the bridge. Third, the beauty of the shape is increased. The four small arches are balanced and symmetrical. The large arch and the small arch form a complete picture, which is more light and beautiful, reflecting the complete unity of architecture and art. Fourth, in line with the theory of structural mechanics, the open shoulder arch structure makes the bridge in a favorable condition when carrying, which can reduce the deformation of the main arch ring and improve the bearing capacity and stability of the bridge.
3. Single hole
. In the traditional construction method of ancient China, the long bridge usually adopts the porous form, so that the span of each hole is small, the slope is gentle, and it is easy to build. However, the multi span bridge also has some disadvantages, such as many piers, which is not conducive to the navigation of ships, but also hinders the flood discharge; the piers are subject to the impact and erosion of water for a long time, and are easy to collapse over time. Therefore, when designing the bridge, Li Chun adopted the form of single hole long span, with no pier in the middle of the river, making the stone arch span as long as 37 meters. This is an unprecedented initiative in the history of Chinese bridges.
Zhaozhou Bridge not only has unique design, but also has a lot of creativity.
1. The choice of bridge site is reasonable
To make the bridge foundation stable. According to his rich practical experience for many years, Li Chun, after strict and careful exploration and comparison, chose a relatively straight place on both sides of the He River to build the bridge. The stratum here is formed by the alluvial water of the river. The surface of the stratum is the coarse sand layer washed by the water for a long time, and the following is the fine stone, coarse stone, fine sand and clay layer. According to modern calculation, the stratum here can bear the pressure of 4.5-6.6 kg per square centimeter, while the pressure of Zhaozhou Bridge on the ground is 5-6 kg per square centimeter, which can meet the requirements of the bridge. After selecting the bridge site, the foundation and abutment were built on it. Up to now, the bridge foundation has only sunk 5 cm, which shows that the stratum here is very suitable for bridge construction.
2. The masonry method of Zhaozhou Bridge is novel and convenient for construction and repair
. Li Chun took local materials and selected the hard blue gray sand and stone produced by nearby counties as the bridge building materials. In terms of stone arch construction method, the longitudinal (along the bridge direction) construction method was adopted. That is to say, the whole bridge is composed of 28 independent arch vouchers juxtaposed along the width direction. The arch thickness is 1.03 meters, and each voucher is operated independently and independently, which is quite flexible After the whole closure, it will form an independent coupon, build a coupon, move the weight-bearing "scaffolding", and then build another adjacent arch. This masonry method has many advantages. It can save the wood used to make the "Hawk frame" and is easy to move. At the same time, it is also conducive to the maintenance of the bridge. If the stone of an arch is damaged, it is only necessary to embed the new stone and carry out local repair, without having to adjust the whole bridge.
3. Many strict measures have been taken to keep the stability of the bridge
. In order to strengthen the transverse connection between the arches, make 28 arches form an organic whole and connect tightly and firmly, Li Chun adopted a series of technical measures. 1) Each arch has adopted the method of widening at the bottom and narrowing at the top, with a slight "score" to make each arch incline inward, squeeze against each other, and strengthen its horizontal connection, so as to prevent the arch stones from toppling outward; a small amount of "score" method has also been adopted in the width of the bridge, that is, gradually shrink the width from both ends of the bridge to the top of the bridge, from the maximum width of 9.6 meters to 9 meters, so as to strengthen the stability of the bridge. 2) Five iron tie rods are evenly arranged along the bridge width direction on the main tie rod to pass through 28 arch ties. The semicircular rod heads at both ends of each tie rod are exposed outside the stone to clamp 28 arch ties and enhance their transverse connection. There is also an iron tie rod on each of the four small arches to play the same role. 3) A layer of arch protection stone is covered on several outer arch stones and the small arches at both ends to protect the arch stone; six hook stones are set on both sides of the arch protection stone to hook the main arch stone to make it firmly connected. 4) In order to make the adjacent arch stones closely fit together, a "waist iron" is worn between the adjacent arch stones on both sides, and the "waist iron" is also worn on the back of the arch between the adjacent stones on each side to chain the arch stones. In addition, the side of each arch stone is chiseled with fine and dense twill to increase the friction and strengthen the transverse connection of each coupon. The adoption of these measures makes the whole bridge connected into a compact whole and enhances the stability and reliability of the whole bridge.
Zhaozhou Bridge
There is a beautiful legend about Zhaozhou Bridge. It is said that Zhaozhou Bridge was built by Luban. After the completion of the bridge, Zhang Guo, one of the eight immortals, rode on a donkey and took Chai Rong to catch up with the excitement. They came to the end of the bridge and happened to meet Luban, so they asked: can the bridge stand up to them. Luban thought: this city
Chinese PinYin : Li Chun
Li Chun
