Information about Bridges and Bridges

Bridges in China have gone through four stages of development. The first stage is mainly in the Western Zhou Dynasty and the Spring and Autumn Period, including the previous historical era, which is the founding period of the ancient bridge. At this time, in addition to the original wooden bridge and Tingbu bridge, there are mainly two forms of bridge: beam bridge and pontoon bridge. At that time, due to the backward level of productivity, most of them could only be built in areas with flat terrain, narrow rivers and gentle water flow, and bridges could only be wooden beams, so the technical problems were relatively easy to solve. On the other hand, pontoons are often used in rivers with wide water surface and fast flowing water.

The second stage is dominated by Qin and Han dynasties, including the Warring States and the Three Kingdoms, which is the period of creation and development of ancient bridges. The Qin and Han Dynasties were a brilliant development stage in the history of Chinese architecture. At this time, not only the bricks of artificial building materials were invented, but also the arch coupon structure with the theme of masonry structure system was created, which created the prerequisite for the emergence of arch bridges later. The appearance of ironware in the Warring States period also promoted the multi-faceted utilization of stone materials in buildings, thus adding new components such as stone pillars, Liang Shi and stone bridge surfaces to the log beam bridge. Not only that, but also its great significance lies in the stone arch bridge came into being. The establishment of stone arch bridge has played an epoch-making role in the history of ancient bridge construction in China, which is not only practical, but also economical and beautiful. The great development of Liang Shi stone arch bridge not only reduces the maintenance cost and prolongs the service life of the bridge, but also improves the scientific level of structural theory and construction technology. Therefore, the use of building stone and the emergence of arch coupon technology in Qin and Han dynasties are actually a major revolution in the history of bridge construction. Therefore, according to some documents and archaeological data, about the Eastern Han Dynasty, four basic bridge types, namely, beam bridge, pontoon bridge, cable bridge and arch bridge, were formed.

The third stage is dominated by the Tang and Song Dynasties, including the Jin, Southern and Northern Dynasties and the Sui, Tang and Five Dynasties, which is the heyday of the development of the ancient bridge. Compared with Qin and Han Dynasties, Sui and Tang Dynasties had stronger national strength, and Tang and Song Dynasties achieved long-term stability and unity. The level of industry and commerce, transportation and science and technology was very developed, and it was the most advanced country in the world at that time. After the Eastern Jin Dynasty, because a large number of Han nobles moved south, the economic center moved from the Yellow River basin to the Yangtze River basin, which made the economy of the southeast water network area develop greatly, and the development of economy and technology in turn stimulated the great development of the bridge. Therefore, many bridges that attracted worldwide attention came into being at this time, such as Zhao Zhouqiao, which was an open-shouldered stone arch bridge initiated by Li Chun, a stonemason in Sui Dynasty, Hongqiao, a stoplog wooden arch bridge invented by abandoned soldiers in Northern Song Dynasty, and Wan 'an Bridge in Quanzhou, which was founded by recitation, and Xiangzi Bridge in Chaozhou, Guangdong Province, which was a combination of Liang Shi Bridge and telescopic pontoon bridge in Southern Song Dynasty. These bridges are very famous in the history of bridges in the world, especially in Zhao Zhouqiao. Seven centuries later, similar bridges appeared in other countries in the world. Throughout the history of Chinese bridges, almost all major inventions and achievements, as well as bridges that can compete for the first place in the world, were produced at this time.

The fourth stage is Yuan Dynasty, Ming Dynasty and Qing Dynasty, which is the saturation period of bridge development, and there are almost no major innovations and technological breakthroughs. At this time, the main achievement is to repair and transform some ancient bridges, leaving many construction documents for bridge construction, providing a lot of written materials for future generations. In addition, some arduous projects, such as Wannian Bridge in Cheng Nan, Jiangxi and Panjiang Bridge in Guizhou, were completed. At the same time, Sichuan, Yunnan and other places have built many cable bridges, and the construction technology of cable bridges has also improved. In the late Qing Dynasty, that is, 188 1 year, with the opening of the first railway in China, another technological revolution in the history of Chinese bridges was ushered in.

Bridges can be divided into wooden bridges, stone bridges, brick bridges, bamboo bridges, rattan bridges, iron bridges, salt bridges and ice bridges.

Wooden bridge is the earliest form of bridge. Almost all bridges before Qin and Han Dynasties in China were wooden bridges. Such as the earliest wooden bridge and wooden column beam bridge. Boat bridges appeared around Shang and Zhou Dynasties, and row-column wooden beam bridges and outboard wooden beam bridges appeared around Warring States Period. However, due to the characteristics of wood itself, such as looseness, perishable, and dominated by the strength and length of materials, it is not only difficult to build bridges on rivers with wide rivers, but also difficult to build durable bridges. So in the Northern and Southern Dynasties, it was replaced by a bridge with mixed wood and stone.

Stone and brick bridges. Generally speaking, the bridge deck structure is also a bridge made of stone or brick, but bridges made of pure brick are rare, usually made of brick, wood or masonry, and stone bridges are more common. During the Spring and Autumn Period and the Warring States Period, a wooden bridge with stone piers appeared, and the Western Han Dynasty further developed into a Liang Shi bridge with stone pillars, and a single-span stone arch bridge appeared in the Eastern Han Dynasty. In the Sui Dynasty, the world's first single-hole arc stone arch bridge with shoulder was born, while in the Tang Dynasty, Li Zhaode created a porous Liang Shi bridge. The Song Dynasty witnessed the vigorous development of large stone bridges, creating Liang Shi Bridge which spans several miles at the intersection of rivers and seas, such as Luoyang Bridge and Ping 'an Bridge in Quanzhou, and large stone arch bridges, such as Lugou Bridge in Beijing and baodai bridge in Suzhou.

Bamboo bridge and rattan bridge. Mainly distributed in the south, especially in the southwest. Generally, it is only used on rivers with narrow river surface, or as a temporary crossing. In the early days, it was mainly a cable bridge. In the Northern and Southern Dynasties, the bamboo cable-stayed bridge was called "Ruxiang Bridge". Later, bamboo cable bridge, bamboo pontoon bridge and bamboo slab bridge appeared. In ancient times, iron bridges included iron cable bridges and iron column bridges. The former belongs to the category of cable bridge, which is relatively common and appeared in the Tang Dynasty. The latter is a kind of beam bridge, which is actually a wood-iron mixed bridge, which is relatively rare. Jiangxi has seen an example.

Salt bridge and ice bridge. Mainly exists in special natural environment. The former is mainly found in salt lake area of Qinghai, while the latter is mainly found in cold areas in the north.

According to the structure and appearance of bridges, there are four basic types: beam bridge, pontoon bridge, cable bridge and arch bridge.

Beam bridge, also known as flat bridge and span bridge, is a bridge supported by piers at a horizontal distance, and then beams are erected to tile the deck. This is the most widely used bridge, which appeared earlier than other bridges in history. It takes the form of wood, stone or a mixture of wood and stone. In the pre-Qin period, all beam bridges used wooden columns as piers, but this kind of wooden column beam structure showed its weakness very early and could not adapt to the development of the situation. Therefore, it was replaced by the Shizhu wooden beam bridge, such as the multi-span long bridge built in Qin and Han Dynasties: Wei Qiao, Baqiao, etc. About the Han Dynasty, the pile foundation technology was invented, and stone piers appeared, which showed that bridges made of wood and stones could cross wider rivers and bear the impact of rough waves. However, because the wooden beam on the stone pier is not resistant to wind and rain erosion, a bridge house was built on the bridge to protect the bridge body. This type of bridge (covered bridge) is more common in the south, but it was first seen in the Yellow River basin. Small and medium-sized Liang Shi or stone slab bridge is the most popular bridge type for its convenient structure, durable materials and labor-saving maintenance. Especially after the Southern Song Dynasty, it was very popular in Quanzhou, Fujian, and many Liang Shi bridges were created. If there is no pier in the middle of a beam bridge, it is called a single-span beam bridge; If there are piers 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.

The pontoon bridge is also called pontoon bridge, pontoon boat and pontoon truss. Because it is easy to erect, it is often used in military affairs, so it is also called "Zhanqiao"-a bridge where hundreds of wooden boats (including rafts or bamboo rafts on the water) are placed side by side on the water with chains, and the boats are paved with boards for people to pass. If the bridge in the strict sense is marked by crossing the air and having column piers, it is not a bridge in the full sense. The pontoon bridge is mainly built where the river is too wide, too deep or fluctuating, which is beyond the reach of ordinary wooden columns and bridges. Wooden stakes, iron oxen, iron mountains, Shi Zhuan and stone lions are set on both sides of the pontoon bridge, and ropes are used. Tianjin Bridge, built on the Luoshui River in the first year of the Sui Dynasty, was the first pontoon bridge to connect ships with chains. At present, pontoon bridges are still widely used in southern China, such as Jiangxi, Zhejiang and Guangxi.

Cable bridge is also called suspension bridge, cable bridge and suspension bridge. , is a bridge suspended with bamboo cables or rattan cables and iron cables as the backbone. Most of them are built on steep river banks and dangerous valleys, and the current is too fast to be used as docks, mainly in the southwest of China. Its practice is to build houses on both sides of the river, set up posts for tying ropes and rotating posts for twisting ropes respectively, then tie several thick ropes flat, and then put boards horizontally on the ropes, and some even add one or two ropes on both sides as handrails. It was first seen in Qin and Han Dynasties. For example, Qin built a bamboo cable bridge in the southwest of Yizhou (now Chengdu) in Sichuan, also called Yili Bridge. The existing famous ones are Luding Iron Cable Bridge and guanxian Bamboo Cable Bridge built in Ming and Qing Dynasties. Crossing the cable bridge feels very thrilling, just as the ancients described the cable bridge: "People are hanging in the air, and if they don't quit in an instant, they will fall into a bottomless valley." Monk Zhimeng in the Tang Dynasty said, "If you can't see the end, the shadows are fighting." In fact, it is still safe to really cross the past, just like Xu Xiake's Travels commented on the Panjiang Bridge in Guizhou: "Look at it and you will stop."

Arch bridge appeared late in the history of Chinese bridges, but once the arch bridge structure was adopted, it developed rapidly and became the most vital bridge type in ancient bridges. Even today, it still has broad prospects for further development. Arch bridges are divided into stone arch bridges, brick arch bridges and wooden arch bridges, among which brick arch bridges are rare and only occasionally used in temples or gardens. Stone arch bridges are commonly used and can be divided into single arch, double arch and multi-arch. The number of arches depends on the width of the river. Generally, the arch in the middle is particularly high, and the arches on both sides are slightly smaller. According to the shape of the arch, there are pentagons, semicircles, pointed arches and flat arches. The bridge deck is generally paved with stone slabs, and the side of the bridge is paved with stone railings. The image of the arch bridge was first seen in the portrait bricks in the Eastern Han Dynasty. It was produced by the shape of the wooden and Liang Shi bridge with outriggers, and was influenced by the shape of the tomb arch and water pipes. Documentary records can be found in Zhu in the Southern and Northern Dynasties. The earliest existing physical object is the Zhao Zhouqiao designed and built by Li Chun in Sui Dynasty. After the Ming dynasty, especially in the Qing dynasty, stone arch bridges issued whole coupons, that is, "bucket coupons."

In addition, other special shapes include Feiting plank road, access bridge, fiber bridge, curved bridge, fish pond flying beam and Feng Shui bridge.

"Feiting", also known as Pavilion Road and Courtyard Road, is the overpass. The crossing passage between ancient palaces and pavilions. "Three Auxiliary Huang Tu": "It is in the palace (referring to the central palace at the end of the Han Dynasty) that the flying pavilion is connected with Zhang Jian Palace and the road is built up and down." During the Qin and Han dynasties, the main halls of the palace were connected by pavilions and roads. Because there was a way up and down, it was called the complex road. Qin Shihuang built a pavilion road from Epang Palace to Lishan, on the footbridge and under the vehicle bridge, which was the earliest overpass in China. "plank road", also known as stack pavilion, bridge pavilion and single-arm wooden beam bridge. A road paved with wooden frames in steep places in mountainous areas.

"Canal Bridge" is not only a water diversion channel, but also a bridge for pedestrians. That is to build a canal on the bridge to divert water. For example, Huiyuan Bridge in Hongdong County, Shanxi Province was built in the Jin Dynasty. Therefore, there is still slang for "water bridge, there is water on the bridge" in Shanxi today. "Fibre Channel Bridge" is a long ribbon bridge parallel to the river, which is built for the convenience of fiber drawing. More common in Zhejiang Canal area. Some are as long as one or two kilometers, or even five or six kilometers. For example, there is a "100-hole Guantang" optical fiber bridge in Ruanshe, Shaoxing, which was built during the Tongzhi period of the Qing Dynasty. The bridge is more than 380 meters long with a span of165,438+05. The bridge deck consists of three stones, with the bottom level with the water surface.

"Curved bridge" is a unique bridge type in gardens, so it is also called garden bridge. Bridges, trails and corridors are all channels for tourists to enjoy the scenery in the garden. "Scenery is more beautiful than curves", so bridges in gardens are often made into curved corners, such as zigzag bridges, forming a broken line that swings back and forth and looks around, so as to extend the landscape and expand the landscape picture. Curved bridges are generally composed of stone slabs and railings. Slates are slightly higher than the water surface, and railings are lower, which makes them seem inseparable from the water surface, and the space seems to be separated from each other, which is especially meaningful.