Who knows the history of Huizhou's "Diaojili" Bridge or anything else about it?

A bridge is an elevated man-made channel. It consists of upper structure and lower structure. The upper structure includes the bridge body and deck; the lower structure includes piers, abutments and foundations. They hang high and lie low, with various shapes. Some of them are located in the mountains and wild ridges, simple and elegant; some span between rocks and streams, adding to the splendor of the mountains and rivers; some are located on the thoroughfares of downtown, with ingenious shapes; some are multi-purpose bridges and are ingenious. No matter the wind or rain, no matter the scorching heat or winter, they always help pedestrians, carriages and horses cross the river in obscurity. The main purpose of building a bridge is to solve the traffic problem across water or valley, so that transportation vehicles or pedestrians can pass unimpeded on the bridge. From its earliest or most important function, a bridge should specifically refer to a road across water and air. Therefore, the annotation of the jade seal in the field of Shuowen's explanation is: "The word "Liang" means using wood to cross the water, which is now called a bridge." It shows that the original meaning of bridge refers to a passage built with wood on the water, and later it is extended to "built on a cliff" There are overpasses such as "plank roads" on the cliffs and "flying pavilions" built between pavilions and palaces. Modern bridges play an important role in urban traffic. Bridges (overpasses) built from the ground to connect east, west, north and south not only help alleviate traffic jams, but also become a beautiful scenery in modern cities. China is the hometown of bridges. It has been known as the "country of bridges" since ancient times and developed in the Sui Dynasty.

Characteristics

China is a country with many bridges, with many mountains and rivers. It is a world leader in both bridge construction technology and the number of bridges. For thousands of years, bridges have become an indispensable part of people's social life. However, due to the vast territory of our country, from south to north and from east to west, there are great differences in geographical climate, cultural customs and the development level of social productivity. Therefore, each based on their own actual conditions and needs, over a long period of time, they created a variety of bridge forms and gradually formed their own characteristics. Specifically, they have the following characteristics: (1) Region sex. Our country has a vast land, and the bridges between the north and the south and the east and west have formed their own relatively independent styles and characteristics due to the influence of the natural geography and human society where they are located. For example, in the northern Central Plains and the Yellow River Basin, the terrain is relatively flat and there are few rivers and water areas. People mostly rely on mules, horses, carts or push carts to transport supplies. Therefore, the bridges here are mostly wide and majestic stone arch bridges and stone beam bridges to facilitate the passage of ships under the bridges. In the northwest and southwest areas, the mountains are high, the rivers are strong, the valleys are deep, and the cliffs are steep, making it difficult to build bridge piers. Therefore, rattan is often used. Use strips, bamboo ropes, logs and other mountainous materials to build rope suspension bridges or outrigger wooden beam bridges; the coastal areas of Lingnan, Fujian and Guangdong are rich in hard granite stones, so stone bridges are everywhere; and in Yunnan minority areas, bamboo is used In abundance, unique bamboo bridges of all kinds can be seen everywhere. Judging from the style of the bridges, the bridges in the north look rough and simple like the people in the north; the bridges in the south look smart and light like the people in the south. Of course, this is also closely related to physical geography. For example, rivers in the north change greatly due to water flow and are impacted by flash floods and ice, so bridges must be thick and stable; while rivers in the south have gentler water conditions and must be easy to navigate, so The bridge is relatively slender and beautiful. (2) Diversity. Our country is a country with ancient civilization, a vast territory, rich resources, beautiful mountains and rivers, and great differences in geology and landforms between the north and the south, so the technical requirements for bridge construction are also high. Around the Han Dynasty, the four basic types of bridges: beam bridge, pontoon bridge, cable bridge, and arch bridge were all produced. These four types of bridges have evolved according to their different building materials and structural forms: wooden bridge, stone bridge, brick bridge, bamboo bridge, salt bridge, ice bridge, rattan bridge, iron bridge, reed bridge, stone pillar bridge, stone bridge, etc. Pier bridge, overflow bridge, cantilever bridge, covered bridge, wind and rain bridge, bamboo plank bridge, stone plank bridge, opening and closing bridge, zipline bridge, triangular arch bridge, pointed arch bridge, round arch bridge, coupled arch bridge, solid belly Arch bridges, flat arch bridges, free-arch bridges, rainbow bridges, channel bridges, curved bridges, towpath bridges, cross bridges, plank roads, flying pavilions, etc., are almost all available. All forms of ancient bridges can be found in our country. (3) Versatility. When building bridges in ancient my country, craftsmen paid great attention to maximizing the effectiveness of the bridge. They not only considered adapting to local conditions and practicality, but also considered making the bridge as multi-functional as possible. For example, most of the arch bridges in the south of the Yangtze River are flat at both ends and have a high arch in the middle, which not only creates a beautiful arc in shape, but also facilitates boating. The corridor-style bridges that are widely seen in the south more fully reflect the multi-purpose characteristics of a bridge.

In the south, it rains more and the sun shines more, so bridge builders built corridor houses on the bridge. This not only provided pedestrians with a place to take a break from the wind, rain and sunshine, but also increased the weight of the bridge to prevent the bridge from being washed away by floods and played a role. Protect wooden beams and iron cables from corrosion by wind and rain. In particular, many such covered bridges are used as markets, accommodations and commercial activities because they are important points for people to pass by. For example, the Xiangzi Bridge in Chao'an County, Guangdong Province is more than 500 meters long. It is known as "one mile long bridge, one mile city". There is a section of pontoon that can be opened and closed in the bridge to facilitate navigation; corridor houses are built on the bridge. , there is a market behind the building, with shops lined up against each other. From morning to dusk, it is bustling and bustling, and you can even ignore the roaring tide and the wide river surface. Therefore, there is a popular joke among the people, "When you arrive at Xiangqiao, ask about Xiangqiao". (4) Public welfare. Since the bridge was born, it has appeared as a social character unique to the people. Traditional buildings in our country are generally privately owned. Only bridges (except bridges in private gardens), whether built by the government or privately, are publicly owned by society. Therefore, for thousands of years, loving bridges and protecting roads has become a good custom, while "building bridges and paving roads" is a charitable act that benefits the public and is highly praised by the people. Therefore, repairing or building bridges has a broad mass character. Looking at historical records, there are roughly four methods of building bridges in our country: one is private construction, that is, one family builds the bridge independently; the other is fundraising, reporting to the government for support, and working together to build the bridge. This type is the most common, such as the famous Zhaozhou Bridge, Quanzhou Luoyang Bridge, etc., which were all built in this way; the third is official-initiated private repairs, initiated by local officials, with the gentry seconding and pledging donations, and appointing officials or business gentry to preside over Finish. Most of these are larger bridges; the fourth is all constructed with government funds. Therefore, ancient bridges are spread all over our country, and many bridges are built even in remote areas. Its large number and wide distribution rank first in the world.

Origin and Development

Before man-made bridges were built, many natural bridge forms were formed in nature due to the influence of crustal movement or other natural phenomena. For example, the stone beam bridge across the waterfall in Tiantai Mountain, Zhejiang Province, the stone arch bridge (Xianren Bridge) formed by natural erosion in Guixi, Jiangxi Province, and the "single-plank bridge" formed by naturally fallen tree trunks by the river, or the vines entangled on both sides of the river. The natural "suspension bridge" formed together and so on. Human beings get inspiration from these natural bridges and continue to imitate nature in the process of survival. At the beginning, some single-plank bridges were probably built on small rivers or trenches around clan settlements (the reason why bridges were originally called "beams" may be because of such beams), or on narrow bridges. In shallow streams, stones are used to cushion the stone pedals that are slightly above the water one after another, forming a simple "jumping pier" stone beam bridge (this original bridge style is often imitated in the back garden, and is called "Tingbu Bridge"). , "Step Bridge"). These "single-plank bridges" and "jumping bridges" are the most primitive bridges built by humans. Later, with the development of social productivity, they continued to evolve from low-level to high-level, and various span-span bridges gradually emerged. my country's bridges have roughly gone through four stages of development. The first stage is dominated by the Western Zhou Dynasty and the Spring and Autumn Period, including the previous historical eras. This is the founding period of ancient bridges. At this time, in addition to the original single-plank bridge and Tingbu bridge, there were mainly two forms of bridges: beam bridge and pontoon bridge. At that time, due to the backward productivity level, most of them could only be built in areas where the terrain was flat, the river was not wide, and the water flow was gentle. The bridges could only be small wooden beam bridges, and technical problems were easier to solve. On rivers with wider water surfaces and faster currents, pontoons are often used. The second stage is mainly Qin and Han, including the Warring States and the Three Kingdoms, and is the creation and development period of ancient bridges. The Qin and Han Dynasties were a dazzling development stage in the history of Chinese architecture. At this time, not only bricks, an artificial building material, were invented, but also arch structures with masonry structural systems as the theme were created, thus creating prerequisites for the emergence of arch bridges later. The emergence of iron tools during the Warring States Period also promoted the multi-faceted use of stone in construction, so that new components such as stone pillars, stone beams, and stone bridge decks were added to the bridge on the basis of the original wooden beam bridge. Not only that, its great significance lies in the fact that the stone arch bridge came into being. The creation of the stone arch bridge played an epoch-making role in the history of ancient Chinese bridge construction in terms of practicality, economy, and aesthetics. The great development of stone beam and stone arch bridges not only reduces maintenance costs and extends the service life of the bridge, but also improves the scientific level of structural theory and construction technology. Therefore, the use of building stones and the emergence of arch technology in the Qin and Han Dynasties was actually a major revolution in the history of bridge construction. Therefore, judging from some literature and archaeological data, around the Eastern Han Dynasty, the four basic bridge types of beam bridge, pontoon bridge, cable bridge and arch bridge had all been formed.

The third stage is dominated by the Tang and Song Dynasties, supplemented by the Jin Dynasty, the Southern and Northern Dynasties, the Sui Dynasty, and the Five Dynasties. This is the heyday of the development of ancient bridges. The national power of the Sui and Tang Dynasties was stronger than that of the Qin and Han dynasties. The Tang and Song dynasties achieved stability and unity for a long time. Industry and commerce, transportation and science and technology were very developed, making it the most advanced country in the world at that time. After the Eastern Jin Dynasty, due to the migration of a large number of Han noble officials to the south, the economic center moved from the Yellow River Basin to the Yangtze River Basin, which led to great economic development in the southeastern water network area. The great economic and technological development in turn stimulated the great development of bridges. Therefore, many world-famous bridges were created at this time, such as the open-shoulder stone arch bridge-Zhaozhou Bridge pioneered by stonemason Li Chun in the Sui Dynasty, the stacked-beam wooden arch bridge-Hongqiao invented by Feizi in the Northern Song Dynasty, and the raft-shaped foundation created by Memorizing , the Wan'an Bridge in Quanzhou with oyster-planted piers, the Xiangzi Bridge in Chaozhou, Guangdong, which combines the stone beam bridge of the Southern Song Dynasty with a retractable floating bridge. These bridges enjoy a high reputation in the history of bridges in the world, especially the Zhaozhou Bridge. Similar bridges appeared seven centuries later in other countries in the world. Throughout the history of bridges in China, almost all major inventions and achievements, as well as bridges that can compete with the world's number one, were created at this time. The fourth stage was the Yuan, Ming, and Qing dynasties. This was the saturated period of bridge development, with almost no major creations and technological breakthroughs. The main achievement at this time was the repair and transformation of some ancient bridges, and many construction instructions for bridge construction were left behind, providing a large amount of written materials for future generations. In addition, some arduous projects such as the Wannian Bridge in Nancheng, Jiangxi Province and the Panjiang Bridge in Guizhou during the Ming Dynasty were also completed. At the same time, many cable bridges have been built in the Sichuan and Yunnan regions, and cable bridge construction technology has also improved. By the end of the Qing Dynasty, that is, in 1881, with the opening of my country's first railway, another technological revolution in the history of my country's bridges ushered in.

Types and forms

According to the main materials, it can be divided into wood, stone, brick, bamboo, rattan, iron, salt, ice and paper bridge. Single-plank bridge is the earliest form of bridge. It was built before the Qin and Han Dynasties in my country. Bridges are almost always wooden bridges. Such as the earliest single-plank bridges and wooden pillar-beam bridges. Floating bridges appeared around the Shang and Zhou dynasties, and column-arranged wooden beam bridges and outrigger-type wooden beam bridges appeared around the Warring States period. However, due to the characteristics of wood itself, such as pine, which is perishable and is subject to the strength and length of the material, it is not only difficult to build bridges on wide rivers, but also difficult to build strong and durable bridges. Therefore, the Northern and Southern Dynasties began to Replaced by mixed wood and stone or stone bridges. Stone bridge and brick bridge. Generally refers to a bridge whose deck structure is made of stone or bricks. Bridges made of pure bricks are extremely rare. They are usually constructed of a mixture of bricks, wood or masonry, while stone bridges are more common. During the Spring and Autumn Period and the Warring States Period, stone pier and wooden beam span-type bridges appeared. In the Western Han Dynasty, they further developed into stone pillar-type stone beam bridges. In the Eastern Han Dynasty, single-span stone arch bridges appeared. In the Sui Dynasty, the world's first open-shoulder single-span bridge was created. Hole curved stone arch bridge, Li Zhaode built a boat-shaped pier porous stone beam bridge in the Tang Dynasty. The Song Dynasty was a period of vigorous development of large-scale stone bridges, creating stone beam bridges spanning several miles across the intersection of rivers and seas, such as Quanzhou's Luoyang Bridge and Ping'an Bridge, as well as large-scale stone bridges such as Beijing's Lugou Bridge and Suzhou's Baodai Bridge. arch bridge. Bamboo bridge and rattan bridge. Mainly found in the south, especially in the southwest. Generally it is only used on narrow rivers or as temporary crossings. In the early days, it was mainly a kind of cable bridge. In the Southern and Northern Dynasties, the bamboo zipline bridge was called "Zuo Bridge". Later, bamboo cable bridges, bamboo pontoon bridges and bamboo plank bridges appeared. Iron bridges, in ancient times, included iron cable bridges and iron pillar bridges. The former belongs to the cable bridge type, which is more common, and appeared around the Tang Dynasty; the latter belongs to the beam bridge type, and is actually a hybrid bridge of wood and iron, which is very rare, with one example seen in Jiangxi. Salt bridge and ice bridge. Mainly found in special natural environments. The former is mainly found in the Qinghai Salt Lake area, and the latter is mainly found in the cold northern areas. Paper bridges appear in some toys. According to structure and appearance, it is divided into four basic types: beam bridge, pontoon bridge, cable bridge and arch bridge. beam bridge. Also known as flat bridge and empty span bridge, it is a bridge with piers as horizontal distance supports, and then the beams are erected and the bridge deck is flat. This is the most commonly used type of bridge, and it appeared earlier than other bridge types in history. It comes in the form of wood, stone or a mixture of wood and stone. In the pre-Qin Dynasty, beam bridges all used wooden pillars as piers. However, this wooden pillar and wooden beam structure showed its weaknesses very early and could not adapt to the development of the situation. Therefore, they were replaced by stone pillars and wooden beam bridges, such as the multi-span long bridges built in the Qin and Han Dynasties: Wei Bridge, Ba Bridge, etc. Around the time of the Han Dynasty, pile foundation technology was invented, and stone bridge piers appeared, indicating that bridges composed of wood and stone could span wider rivers and withstand the impact of raging floods.

However, because the wooden beams on the stone piers were not resistant to wind and rain erosion, bridge houses were built on the bridge to protect the bridge body. This bridge type (covered bridge) was later more common in the south, but it was first seen in the Yellow River Basin. Small and medium-sized stone beams or stone slab bridges are convenient in structure, durable in materials, and labor-saving in maintenance. They are the most popular bridge shape among the people. Especially after the Southern Song Dynasty, they became very popular in Quanzhou, Fujian, and many long stone beams were created. bridge. If a beam bridge has no piers in the middle, it is called a single-span beam bridge; if there is a pier in the water so that the bridge body forms two holes, it is called a double-span beam bridge; if there are more than two piers, it is called a multi-span beam bridge. pontoon. Also known as pontoon bridge, floating boat, or floating truss, it is also called "war bridge" because it is easy to erect and is often used for military purposes. Bridges on the water) are linked together on the water, and the boats are covered with planks for people and horses to pass. If a bridge in the strict sense is marked by a span and piers, then it is not a bridge in the full sense. Floating bridges are mainly built in places where the river surface is too wide, too deep, or where there are large fluctuations, making it difficult for ordinary wooden and stone column beam bridges to help. There are many pillars or iron cows, iron mountains, stone gates, stone lions, etc. on both sides of the pontoon to tie the cables. The Tianjin Bridge built on Luoshui River in Luoyang in the first year of Daye of the Sui Dynasty was the first pontoon bridge to use iron chains to connect ships. Floating bridges are still commonly used in southern my country such as Jiangxi, Zhejiang, Guangxi and other places. Advantages of pontoon bridges: First, construction is fast. In the second year of Xianfeng in the Qing Dynasty (AD 1852), the Taiping Army besieged Wuchang and built two pontoon bridges across the Yangtze River in just one night. Second, the construction cost is low. Zou Shouyi of the Ming Dynasty once compared stone bridges and pontoon bridges in "Repairing the Fenglin Floating Bridge": "If you use a stone beam bridge, it will cost a thousand gold, but if you use a pontoon bridge, it will only cost five hundred gold. It can be determined according to needs. "Third, it can be opened and closed at will, and it is easy to dismantle and erect. The disadvantage is that it has a small load capacity, fluctuates with the waves, and has a weak ability to withstand floods. It often needs to be dismantled in time and needs to be taken care of. The management is cumbersome. The boat, bridge deck and mooring cables need to be repaired and replaced frequently, and the maintenance cost is high. expensive. Therefore, the final destination of many floating bridges develops into wooden beam bridges, stone beam bridges or stone arch bridges. rope bridge. Also known as suspension bridge, rope bridge, suspension bridge, etc., it is a bridge suspended with bamboo ropes, rattan ropes, iron ropes, etc. as the backbone. They are mostly built on steep banks and dangerous valleys where the water flow is fast and it is difficult to build bridge piers. They are mainly found in the southwest region. The method is to build a house on both sides of the bank, with a rope-tying column and a rope-turning column in each house, and then use a number of thick ropes to tie them flat, and then lay wooden boards across the ropes, and some also add one or two ropes on both sides. as a handrail. It first appeared in the Qin and Han Dynasties. For example, Qin Libing built a Zuo Bridge in the southwest of Yizhou (now Chengdu), Sichuan, also known as "Yili Bridge", which was a bamboo cable bridge. Famous existing ones include the Luding Iron Cable Bridge and the Guanxian Bamboo Cable Bridge built in the Ming and Qing Dynasties. Crossing the cable bridge feels very thrilling, just as the ancients described crossing the cable bridge: "A person is suspended in mid-air, crossing a ravine. If he doesn't stop for a moment, he will fall into a bottomless valley." Zhimeng, a monk in the Tang Dynasty, said: "If you can't see the bottom, you can't see the bottom. "In fact, it is actually safe to cross it, just as "Xu Xiake's Travels" commented on the Panjiang Bridge in Guizhou: "It looks like it is floating, but when you practice it, it remains motionless." It appeared relatively late in the history of bridges in our country, but once the arch bridge structure was adopted, it developed rapidly and became the most vital bridge type among ancient bridges. Even today, it still has broad prospects for continued development. Arch bridges can be divided into stone arches, brick arches and wooden arches. Among them, brick arch bridges are extremely rare and are only occasionally used in temples or gardens. The most common one is the stone arch bridge, which can be divided into single arch, double arch and multiple arch. The number of arches depends on the width of the river. Generally, the arch in the middle should be particularly tall, and the arches on both sides should be slightly smaller. According to the shape of the arch, it can be divided into five sides, semicircle, pointed arch, flat arch, etc. The bridge deck is usually paved with stone slabs and the bridge sides are made of stone railings. The image of the arch bridge was first seen on the portrait bricks of the Eastern Han Dynasty. It was produced by the development of the outrigger wood and stone beam bridge and was influenced by the shapes of tomb arches, water pipes, etc. Documentary records can be found in the "Shui Jing Zhu" of the Southern and Northern Dynasties. The earliest existing object and the most representative one is the Zhaozhou Bridge designed and built by Li Chun in the Sui Dynasty. For the issuance of certificates for stone arch bridges, after the Ming Dynasty, especially in the Qing Dynasty, it was popular to use whole coupons, that is, "barrel issuance". Cable-stayed bridge Concrete cable-stayed bridge Composite beam cable-stayed bridge Steel cable-stayed bridge Other shapes: flying pavilion and plank road, channel bridge and towpath bridge, as well as curved bridge, fish pond flying beam and Fengshui bridge. "Flying Pavilion" is also called Pavilion Road, Fudao, or overpass. Cross passages between pavilions in ancient palaces. "Sanfu Huangtu": "On the west side of the palace (referring to the Weiyang Palace of the Han Dynasty), a flying pavilion was built across the city to connect to the Zhang Palace, and a chariot road was constructed to go up and down." The palaces of the Qin and Han Dynasties were connected by pavilion roads, because there were roads up and down. , so it is called Fudao.

Qin Shihuang's Pavilion Road leads from Epang Palace to Lishan Mountain, with a pedestrian bridge and a vehicular bridge under it. It can be called the earliest overpass in China. "Plank Road", also known as Zhange, Qiaoge, is a single-arm wooden beam bridge. In steep areas of the mountainous areas, there are wooden roads. "Channel Bridge" is both a water diversion channel and a bridge for pedestrians. That is to say, a ditch was built on the bridge to divert water. For example, the Huiyuan Bridge in Hongdong County, Shanxi was built in the Jin Dynasty. Therefore, there is still a slang term among Shanxi people: "bridge on water, water on bridge". "Towpath Bridge" is a long ribbon-shaped bridge parallel to the river built to facilitate fiber pulling. It is more common in canal areas in Zhejiang. Some are one to two kilometers or even five or six kilometers long. For example, there is a "hundred-hole Guantang" towpath bridge in Ruanshe, Shaoxing. It was built during the Tongzhi period of the Qing Dynasty. The bridge is more than 380 meters long and has 115 spans. The bridge deck is made of three strips. It is made of stones, with a flat bottom connected to the water. "Curved bridge" is a unique bridge style in gardens, so it is also called garden bridge. Bridges, paths, and corridors are all passages for visitors to enjoy the scenery in the garden. "Scenery is better than a curve." Therefore, bridges in gardens are often made with folded corners, such as the Jiuqu Bridge, to form a folded line that swings back and forth and looks left and right, thereby extending the scenery and enlarging the landscape. Curved bridges are generally composed of stone slabs and railings. The stone slabs are slightly higher than the water surface and the railings are low, making the bridge seem to be separated from the water surface and the space seems to be separated but not separated. It has a particularly implicit and endless meaning. (1) The use of arc arches has changed the tradition that most large stone bridges in my country are semicircular arches. Most of the arches of ancient stone bridges in my country are semicircular. This form is more beautiful and complete, but it also has two shortcomings: First, transportation is inconvenient. Semicircular bridge arches are more suitable for bridges with smaller spans, while larger spans If a semi-circular arch is used for a span bridge, the vault will be very high, resulting in a high bridge and steep slope, making it very inconvenient for vehicles, horses and pedestrians to cross the bridge. Second, the construction is unfavorable. The scaffolding used for the semicircular arch stone masonry will be very high, which increases the risk of construction. To this end, Li Chun and the craftsmen creatively adopted the arc arch form, which greatly reduced the height of the stone arch. The clear span of the main hole of Zhaozhou Bridge is 37.02 meters, while the arch height is only 7.25 meters. The ratio of arch height to span is about 1:5, thus achieving the dual purpose of low bridge deck and long span, and the bridge deck transition It is stable and very convenient for vehicles and pedestrians. It also has the advantages of saving materials and convenient construction. Of course, the thrust of the arc-shaped arch on the bridge foundations at both ends increases accordingly, which requires higher requirements for the construction of the bridge foundation. (2) Use open shoulders. This is a major improvement Li Chun made to the spandrel. He changed the solid shoulder arch used in the previous bridge construction to the open shoulder arch, that is, two small arches are set up at both ends of the big arch, and the small arch near the big arch foot has a clear span. is 3.8 meters, and the clear span of the other arch is 2.8 meters. This kind of shoulder arch with a large arch and a small arch has excellent technical performance. First of all, it can increase the flood discharge capacity and reduce the impact of floods on the bridge due to the increase in water volume during flood seasons. During the flood season in ancient times, the water potential of the Jiaohe River was relatively large, which was a test for the bridge's flood discharge capacity. Four small arches could share part of the torrent. According to calculations, four small arches could increase the water-crossing area by about 16%, greatly reducing the impact of floods on the bridge. impact and improve the safety of the bridge. Secondly, compared with solid shoulder arches, the open shoulder arch can save a lot of earth and stone materials and reduce the self-weight of the bridge body. It is calculated that the four small arches can save 26 cubic meters of stone and reduce its own weight by 700 tons, thus reducing the impact of the bridge body on the abutment and foundation. Vertical pressure and horizontal thrust increase the stability of the bridge. Thirdly, it increases the beauty of the shape. The four small arches are balanced and symmetrical. The large arch and the small arch form a complete picture, which looks more light and beautiful, reflecting the complete unity of architecture and art. Fourth, in line with the theory of structural mechanics, the shoulder-arch structure puts the bridge in a favorable condition when carrying load, can reduce the deformation of the main arch ring, and improve the bearing capacity and stability of the bridge. (3) Single hole. Traditional construction methods in ancient my country generally use porous forms for longer bridges, so that the span of each hole is small and the slope is gentle, making it easier to build. However, porous bridges also have disadvantages. For example, there are many bridge piers, which is not conducive to boat navigation and hinders the release of floods. The bridge piers are subject to long-term impact and erosion by water flow, and are prone to collapse over time. Therefore, when Li Chun designed the bridge, he adopted the form of a single-hole long span without piers in the center of the river, making the stone arch span as long as 37 meters. This is an unprecedented initiative in the history of bridges in our country.

Materials and Structure

The structure of bridges, except for the more primitive single-plank bridges, Tingbu bridges and pontoon bridges, generally consists of a span-space part and a span-space support part, that is, the bridge pier and the bridge. The bridge body consists of. (1) Beam bridges can be divided into wooden beam bridges and stone beam bridges according to the materials used and structural conditions.

"Wood beam bridges" include wooden beams and wooden pillar bridges, wooden beams and stone pillar bridges, wooden beams and stone pier bridges, and wooden brace bridges. Among them, "wooden beam and stone pillar bridges" are developed from the original wooden bridges of wooden beams and wooden pillars. "Stone beam bridges" include stone beam and stone pillar bridges, stone beam and stone pier bridges, stone outrigger bridges (similar to wooden outrigger bridges), three-sided stone beam bridges, flooded stone beam bridges, and stone slab flat bridges (mostly seen in "curved bridges" in gardens). ” and “Towpath Bridge”). Among them, "stone beam and stone pier bridge" is the most common. This kind of bridge goes one step further than using stone piers and wooden beams, and avoids the shortcomings of wooden beam bridge decks that are prone to decay and often require repairs. There is also a type of bridge that is combined with a pontoon bridge, which is the "opening bridge". The middle pontoon can be opened and closed as needed. Such as the Xiangzi Bridge in Chao'an County. Its east and west ends are stone beam bridges, and eighteen wooden boats are built as pontoons to connect them in the middle to facilitate the drainage of floods and the purpose of "connecting huge ships and discharging wooden rafts". (2) Arch bridges, according to their structural conditions and the arc and arrangement forms of the arches, can be divided into: steep and flat arch arch bridges, pointed arch and round arch arch bridges, continuous arch and fixed-end arch bridges, single-hole and multi-hole arch bridges Arch bridges, solid and open-belly arch bridges, and Hongqiao, etc. The arcs of its arches include semicircles, horseshoes, full circles, pot bottoms, egg circles, ellipses, parabolic circles and folded edges. The arrangement forms include parallel and horizontal connections. Among them, the horizontal connection type is the most used and is derived from There are two types of bordered horizontal coupons and framed horizontal coupons. (3) Cable bridges, according to the use of ropes of different textures, transitions and structural forms, can be divided into bamboo cable, iron cable, rattan cable and zipper bridges, city defense suspension bridges, as well as single cable, double cable, multi-cable mesh bridges, Parallel multiple rope bridges, etc.

Related Arts and Literature

Landscapes are naturally beautiful, because Chinese writers and artists have a special liking for them. Just as Dong Qichang, a great artist of the Ming Dynasty, said, "Poetry takes mountains and rivers as its environment, and mountains and rivers also take poetry as its environment." Bridges are buildings erected between mountains and rivers. They have stood in nature for a long time, and have become embellishments and beautifications of the landscape. A natural member. Wherever there are mountains and rivers, there will naturally be bridges. The bridges themselves are also a fusion of practicality and art, such as the straightness of the bridge, the soaring air of the cable bridge, the charm of the pontoon bridge, the shadow of the arch bridge, etc., which originally swayed the style of art. Therefore, the British Mr. Joseph Needham said: "There is no Chinese bridge that is less beautiful, and many of them are of outstanding beauty." The artistry of my country's bridges is mainly reflected in two aspects, namely, modeling style and decorative craftsmanship. The modeling style is mainly reflected in the soft curves, rhythmic coordination and majesty. Some small beams and thin bridges in the Jiangnan water towns are more reminiscent of the poetic and picturesque concept of "small bridges, flowing water, and people's houses". Bridge decoration is generally not very developed in our country. It is mainly reflected in stone bridges, and its locations are generally in places where people can easily stop and look. For example, the common ones include dragons, phoenixes, lions, elephants, and rhinoceroses, as well as rabbits, monkeys, horses, dogs, clouds, lotuses, grasses and other patterns. There are also a few reliefs of river gods, warriors and characters and stories. For example, the head of the river god is embossed on the flower wall of Yongtong Bridge in Zhaoxian County, Hebei Province, the chilong is embossed on the railings of Zhaozhou Bridge and the lion head is on the pillar, and the stone lion on the pillar of Marco Polo Bridge in Beijing, etc. These stone carvings are of exquisite craftsmanship and are often closely related to folk customs, myths and legends. Such as the dragon that controls water, the rhinoceros that divides water, the mythical beast that subdues water monsters, etc., thus forming a unique style of bridge art in my country. In addition, many bridges in our country often have many ancillary buildings built on the bridge or on the bridge head. The construction of buildings on bridges began with the anti-corrosion and foundation-pressing functions of wooden bridges, and later became a combination of bridges and buildings. The building at the bridge head serves as a symbol of the bridge's entrance and exit, and also plays the role of setting off, guarding and decorating the bridge.

Legends and stories of the bridge

Tanqin Bridge - A few hundred meters north of Nanqiao Town, there was a small stone bridge named Tanqin Bridge. It is said that a long time ago, there was an official named Qian who had three daughters. The youngest daughter played the piano well. There was a young man named Han Chong nearby, who was also a master at playing the piano. As time passed, the two became close friends and fell in love, but Mr. Qian refused, so the daughter had to persuade Han Zhong to go to the capital to study piano and gain fame so that her father would agree to their marriage. Han shed tears and left. But Qian forced the little girl to marry a powerful man. The little girl missed Han Zhong and died with hatred. Soon, Han Chong returned and learned that his lover had passed away. He sat cross-legged on the small stone bridge and played sad songs to express his memory. After playing, he took the harp and threw himself into the river. Mahjong Bridge - During the Daoguang period of the Qing Dynasty, a bridge was built on the Jinghe River in Huazhi, named Mahjong Bridge. There was no bridge here before, making it very inconvenient for pedestrians. There was a local old man surnamed Zhou who hated private gambling very much. He invited more than 10 knowledgeable people to surround the casino, catch the gamblers, confiscate their financial bets, and destroy their belongings. The bridge was built with the confiscated gambling money. Now it has been destroyed.