In the history of human civilization, bridges occupy an important page. China is a great country with a written history of 5,000 years. The Yangtze River, Yellow River and Pearl River basins have nurtured the Chinese nation and created splendid Chinese culture. The brilliant achievements of ancient bridges in China once occupied an important position in the history of bridge development in the world and were recognized by the world. /kloc-in the 8th century, the British industrial revolution brought up modern science and technology./kloc-in the 9th century, modern steel-making method and concrete as artificial stone material were invented, which made European and American countries enter a new era of modern bridge engineering. /kloc-The Opium War in the middle of 0/9th century reduced China to a semi-colonial and semi-feudal country. In order to plunder China's resources, the imperialist powers built railways, opened mines and set up concessions in China, and introduced modern bridge technology. 1937 Qiantang River Bridge is the first modern steel bridge designed and supervised by China engineers. After the founding of New China, Wuhan Yangtze River Bridge was built with the help of Soviet experts, and advanced bridge technology was introduced at that time. China's reform and opening up in 1980s ushered in the golden age of bridge construction. On the basis of learning from the innovative technology of developed countries, Chinese bridges rose and took off in the 1990s through independent construction, and made remarkable progress and achievements. It can be said that China's bridges have embarked on the road of revival, and they are moving from a big bridge country to a strong bridge country, hoping to reproduce their glory in the independent innovation efforts in the 2 1 century.

The Rise and Fall of Ancient Bridges in China

The four great inventions are China's great contribution to human civilization, and in terms of ancient bridges, China's ancestors also have many world-recognized achievements. In the History of Science and Technology in China and the History of Science and Civilization in China, Dr. Joseph Needham, a British historian of science and technology, made detailed comments and textual research on the development of ancient bridges such as beam bridges, pontoons, arch bridges and cable bridges in China.

Liang Shi bridge

The earliest recorded girder bridge in the history of China is the giant bridge. The bridge was built in Shang dynasty (16 ~ 1 1 century). "King Wu of Zhou hacked, and merchants sang, and millet accumulated at the bridge to help the poor." In ancient times, the span of Liang Shi Bridge was generally below 10 meter, and the largest Liang Shi was 23.7 meters long. The ancient bridge in Liang Shi, China, which has been preserved to this day, was built in Anping Bridge, Quanzhou, Fujian in the eighth year of Shaoxing (1 138). The bridge has 362 holes, with a total length of 5 miles (2,223 meters). And the earlier Luoyang Bridge in Quanzhou, built in the fifth year of Song Dynasty (1053), with a total length of 1097 meters and a span of 47. Italian Kyle Poirot wrote this in his travel notes 1275.

float bridge

The Book of Songs says, "Welcome Wei, build a ship as a beam." In BC12nd century (BC 1 135), Zhou Wenwang got married and built a pontoon bridge on the Weihe River. Later, during the Spring and Autumn Period, the Warring States Period and even the Qin and Han Dynasties, due to the needs of war, pontoons were erected on the Yellow River, Weihe River and Luohe River many times, and chains were used instead of bamboo ropes as the connection between ships.

According to western historical records, the earliest pontoon bridge began in the Persian pontoon bridge in the 5th century BC. In 493 BC, Darius, king of Persia, marched into Greece. In order to cross the Istanbul Strait (Bosphorus Strait), 360 warships were arranged downstream, and 2 million people crossed the bridge in 7 days and 7 nights.

stone arch bridge

Inspired by the naturally formed arched caves, in 6000 BC, the ancestors of the two river basins began to build arch rings with bricks. It should be said that the four ancient civilizations have mastered the technology of building arches and arch bridges with bricks and stones. It can be speculated that China also learned to build arch bridges in Shang Dynasty. The ancient arch bridge was originally a semicircular arch. In BC 1 century, the Romans built many famous water conveyance arch bridges, which are called "Roman stone arch bridges" in the world. Up to now, there are still more than 30 arch bridges, and they have begun to break through the convention of semi-circular arches and build arc arches smaller than semi-circular.

Anji Bridge in Zhaozhou, Hebei Province was built by Li Chun, an outstanding craftsman in the Sui Dynasty of China. It was built in 665438 A.D., and it is an original masterpiece. The main span of the bridge is 37.4 meters, up by 7. 1 meter. Two small arches (called abdominal arches) are built on both sides of the arch shoulder to form an empty arch bridge, which not only reduces the self-weight, but also is beneficial to flood discharge. This kind of "open-shouldered arch" initiated by China did not appear in Europe until14th century, which may be related to the information of ancient bridges in China conveyed in13rd century The Travels of Marco Polo.

There is a wonderful description in The Travels of Marco Polo written by Kyle Polo: "There is a beautiful bridge on the river. The beauty of the bridge is everywhere, which is really rare ... It is well built. Frankly speaking, it is the best and unique bridge in the world ... ". He is talking about Lugou Bridge in the southwest suburb of Beijing. Lugou Bridge was built in the 29th year of Dading in Jin Shizong (1 189) and in the 3rd year of Mingchang in Zhang Zong (1 192). The total length is 2 12.2 meters, and the total length of approach bridges at both ends is 266.5 meters, which is 1 1 span arc arch bridge. On the bridge arch, the frame-type longitudinal arch-building method is adopted to make the whole arch piece become a closed whole. There are 279 bluestone fences and 28 1 watchpost on both sides of the bridge deck, on which 489 stone lions of different sizes and expressions are carved. The completion of Lugou Bridge facilitates the traffic between Jinzhong and the south. It is magnificent in engineering, scientific in structure, superb in skill and beautiful in shape, representing the achievements of ancient science and technology in China.

Cantilever wooden beam bridge

Folding wooden beams into a bucket arch shape or adding diagonal braces to increase the cantilever capacity until the middle span is closed, forming an arch bridge with a span of more than 30 meters, which is the original creation of ancient Chinese craftsmen and can still be seen in Sichuan-Tibet area in the west and Zhejiang-Fujian area in the southeast. The most famous is the Hongqiao in Bianjing (now Kaifeng, Henan), the capital of the Northern Song Dynasty, in the Riverside Scene at Qingming Festival painted by Zhang Zeduan in the Song Dynasty. The span of the bridge is about 18.5m, the width of the bridge is 9.6m, and the arch vector is about 4.2m At that time, it was called "crossing the wood" bridge method. In the Yuan Dynasty, this type of bridge was brought to Europe by the Mongolian army, and a bridge across the Danube was built.

cable bridge

Using natural plant fibers (such as rattan, hemp and bamboo strips) to make cable bridges is a natural creation of ancient ancestors in subtropical areas at home and abroad. China began to build cable bridges about 3000 years ago. There is a record of crossing the western regions with ropes in Biography of Han Dynasty, which shows that the Tibetan and Yi ethnic minorities in the western regions have made important contributions to the cable bridge initiated by China.

Zhupu Bridge in Dujiangyan, guanxian, Sichuan Province is an outstanding representative of existing ancient bamboo cable bridges in China. China was the first country to invent iron smelting technology, and at the latest in the Sui and Tang Dynasties (6th century), there was an iron chain bridge. 1665, Xu xiake's "the story of iron cable bridge" described in detail a iron cable bridge about 122 meters long in Guizhou. 1667, French missionaries published the book Wonders of China, which also introduced the China Tiesuo Bridge. Dr Needham of Britain pointed out that these two books directly inspired the western attempts to build cable bridges.

Tiesuo Bridge in Dadu River, Luding County, Sichuan Province was built in the 44th year of Qing Emperor Kangxi (1705), which is the representative of Tiesuo Bridge in China. The span of the bridge is about 100 meter, and the width of the bridge is 2.8 meters. 13 Bowl-mouth thick iron chains, and the bridge deck is paved with wooden boards, which is an important passage for Sichuan and Tibet.

2 1 Century Prospect of Chinese Bridges

After entering the 2 1 century, China, together with the developed countries in the world, is facing a more magnificent sea-crossing bridge project, in order to realize the dream of land transportation network on four continents. The East China Sea Bridge under construction in China, the Hangzhou Bay Passage Project, the Zhoushan Island Link Project, and the planned Lingdingyang and Qiongzhou Strait across the Bohai Strait, Jiaozhou Bay and the Pearl River Estuary.

The Taiwan Province Strait project is a challenge for Chinese bridge engineers. Facing the complex natural conditions and harsh environment of super-long-span bridges, ultra-deep water foundations and the sea, we must achieve leap-forward development through innovation and improve our competitiveness.

China's bridge industry should recognize the gap, not be unwilling to lag behind, adhere to the principle of independent design and construction, gain experience and progress through practice, overcome shortcomings and deficiencies, win the respect of international counterparts with a large number of beautiful bridges with advanced technology, reasonable economy and excellent quality, and reproduce the glory of China ancient bridge.