I want to learn about bridge cranes, but I don’t have relevant information. Please ask the masters to help me and introduce the structure and operation of bridge cranes. It would be better if there are pictures or related websites. Thank you.
1. The concept of bridge
Bridge: qiao, upper tone (second tone), ten strokes, left and right structure. Mubu. Wubi: STDJ.
Definition:
1. A building erected on the water or in the air to facilitate traffic; such as an overpass.
2. It is a metaphor for people or things that play a role in communication.
3. Surname.
What this entry is going to express is the first meaning of bridge.
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, and come in various shapes. Some of them are located high 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 busy cities, with ingenious shapes; some are multi-purpose bridges and are ingenious. Regardless of the wind or rain, the scorching heat or the severe winter, they always help pedestrians, carriages and horses cross the river in obscurity.
2. The significance and characteristics of bridges
The main purpose of building bridges is to solve traffic across water or valleys, so that transportation vehicles or pedestrians can flow 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 Jie 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 the passage of wood on the water, and the extension behind it means that it is built on the cliff. There are overpasses such as "plank roads" on the cliffs and "flying pavilions" built between pavilions and palaces.
China is a country with many mountains and rivers. In ancient times, it was 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, based on their own actual conditions and needs, over a long period of time, each created a variety of bridge forms and gradually formed their own characteristics. Specifically, they have the following characteristics:
(1) Regionality. 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 natural geography. For example, rivers in the north change greatly due to water flow and are impacted by flash floods and ice, so the bridges must be thick and stable; while the rivers in the south have gentle 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, abundant 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.
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 from the Qin and Han Dynasties, including the Warring States and the Three Kingdoms, and is the period of creation and development 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, a man-made 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, including the Jin Dynasty, the Southern and Northern Dynasties, the Sui Dynasty, and the Five Dynasties period. This was 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 is the Yuan, Ming and Qing dynasties. This is 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.
4. Types and forms of bridges
The types of bridges, if divided by the main materials for building bridges, include wood, stone, brick, bamboo, rattan, iron, salt, Ice bridge and so on.
Wooden bridges are the earliest form of bridges. Almost all bridges in my country before the Qin and Han Dynasties were 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 easy to rot 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 Southern and Northern Dynasties began to Replaced by mixed wood and stone or stone bridges.
Stone bridges and brick bridges. Generally speaking, it refers to a bridge whose deck structure is also made of stone or bricks. However, bridges made of pure bricks are very rare. They are usually constructed of a mixture of bricks, wood, or masonry, while stone bridges are more common.
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 and closing 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 used to form a pontoon bridge in the middle to connect them to facilitate the drainage of floods and the purpose of "passing through huge ships and discharging wooden rafts".
(2) Arch bridges, according to their structural conditions and the arc and arrangement 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 Arch bridges, single-hole and multi-hole arch bridges, solid-web and hollow-web arch bridges, Hong Bridge, 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 cables, iron cables, rattan cables and zipline bridges, city defense suspension bridges, as well as single cable and double cable bridges. , multi-cable mesh bridge, parallel multi-cable bridge, etc.
6. The Art and Literature of Bridges
Chinese writers and artists have a special liking for the natural beauty of landscapes. As Dong Changqi, a great artist of the Ming Dynasty, said, "Poetry takes mountains and rivers as its environment, and mountains and rivers also form poetry's environment." A bridge is a building erected between mountains and rivers. It has stood in nature for a long time, and has become an embellishment and beautification 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 our 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.
Margou Bridge is a national key cultural relic protection unit. It is located in Wanping City, Fengtai District, southwest of Beijing, across the Yongding River. It was first built in the 29th year of Dading of Jin Dynasty (1189) and completed in the third year of Mingchang (1192). Rebuilt during the Ming Dynasty and Qing Dynasty, it is the oldest existing stone arch bridge in Beijing. The bridge is made of white stone, 212.2 meters long and 7.5 meters wide. There are railings and pillars on both sides. There are 492 large and small stone lions carved on the pillars with different expressions. The bridge has 11 holes, and the piers and arches are all fixed with waist iron. The bridge piers are in the shape of a boat, and the bridge piers are built in the shape of a boat to divert water. There are a pair of Chinese watches at both ends of the bridge, and a stone tablet on each side. One is a tablet for the bridge construction during the Kangxi period of the Qing Dynasty, and the other is a tablet inscribed by Emperor Qianlong "Lugou Xiaoyue", which is one of the "Eight Scenic Spots of Yanjing". To the east of the bridge is Wanping City. On July 7, 1937, the Japanese army bombarded Marco Polo Bridge and attacked Wanping City, and the Anti-Japanese War broke out. This was the famous "Marco Bridge Incident", and the bullet marks from that year can still be seen on the bridge.
Zhaozhou Bridge, also known as Anji Bridge, also called Dashi Arch Bridge, is located on the Qingshui River five miles south of Zhao County, Hebei Province. It is not only the first stone arch bridge in China, but also the first stone arch bridge in the world today. The literati of the Tang Dynasty praised the bridge as "the first clouds rise above the moon, and the rainbow drinks from the stream."
This bridge was built from 605 to 618 AD in the Sui Dynasty by Li Chun, an ordinary stonemason. It has a history of more than 1,350 years. In the long years, although it has been tested by countless floods, wind and rain, erosion by ice, snow, wind and frost, and eight earthquakes, it has remained safe and sound, standing tall and tall on the Qingshui River.
The Zhaozhou Bridge designed by Li Chun is 50.82 meters long and 9.60 meters wide. The clear span of the large arch is 37.37 meters long and the arch height is 7.23 meters. He considered that in order to make the slope of the bridge deck small, the ratio of the bridge height to the span should be 1:5, which would facilitate pedestrians and vehicles; the high arch would also facilitate boating under the bridge. He also made two small arches on each shoulder of the big arch, making the entire bridge look particularly balanced and symmetrical, which not only facilitates flood discharge in the rainy season, but also saves building materials. Its structure is majestic, ingenious, and well-organized, and has been imitated by later generations. The bridge deck designed by Li Chun is straight and divided into three sections, with carriages and horses in the middle and pedestrians on both sides, which not only maintains order but also prevents traffic accidents. It can be seen that more than 1,300 years ago, when the technology was very backward, it was really rare that Li Chun, an ordinary stonemason, had such superb skills.
The stone materials and stone masonry techniques used by Li Chun are unique. He used rectangular stones, each weighing about one ton. In the Sui Dynasty more than 1,350 years ago, it was very difficult for Li Chun to transport such heavy stones without cranes and cranes. This fully demonstrates the great wisdom of our country's working people. It can be seen how much effort and price Li Chun paid!
Li Chun led other craftsmen to chisel fine diagonal lines on each face of the stone so that the stones can interlock and fasten together. The entire bridge is composed of 28 independent stone arches juxtaposed longitudinally. He thought that this would allow each stone arch circle to bear its own load independently and facilitate repairs. In order to strengthen the connection between the arch circles, he used nine iron beams to penetrate the back of the arch, and then embedded the waist iron between the arch stones, so that the bridge could be "kept and protected in a clever way and used in the world."
Finally, Li Chun organized skilled craftsmen to carve many exquisite classical carvings on the stone railings on both sides of the bridge, with delicate patterns, vigorous knife skills, flexible carvings, and various birds and animals. The dragon is soaring and the tiger is leaping, as if it is about to fly, and the image is lifelike. It can be called a masterpiece of sculpture art in the Sui and Tang Dynasties. This new type of bridge with arches on top of arches and "open-shoulder arches", such a layout, using such a giant span, and forming such a beautiful shape were the first of its kind in the world by Li Chun. In Europe, the Serret Bridge on the Teck River in France did not appear until the 14th century. However, it was more than 700 years later than the Zhaozhou Bridge in China, and it had long been destroyed by floods. Therefore, the Zhaozhou Bridge built by Li Chun is the only one that has survived for the longest time in the history of bridge construction in the world. It occupies an important position in the world and is quite valuable. This is the pride and pride of the Chinese people.
This Zhaozhou Bridge, which has a long history, unique structure, beautiful appearance and ranks first in the world, embodies Li Chun’s sweat and hard work. Li Chun became the first bridge expert in the history of architecture in China and even the world.
However, no more records were left about Li Chun’s life story. Even people from the Tang Dynasty after the Sui Dynasty only had a few records such as "the person who made the peculiar Zhaozhou Bridge was the Sui craftsman Li Chun". In the 13th year of Kaiyuan of the Tang Dynasty (726 AD), 100 years after the Zhaozhou Bridge was built, Zhang Shizhen briefly mentioned in the "Anji Bridge Inscription": "The Qingshui River Stone Bridge in Zhaozhou is the trace of Sui craftsman Li Chun, and it was built Strange, people don’t know what they do.” This shows that in feudal society, how many creations and inventions of the working people were buried.
What is particularly worth mentioning is that the foundation of Zhaozhou Bridge is very solid. Over the past 1,350 years, the subsidence level of the bridge foundations on both sides has only differed by 5 centimeters, which shows that the location selection of Li Chun Bridge was scientific and reasonable. The Zhaozhou Bridge foundation is built on the white coarse sand layer of the Qingshui River bed. There are neither piles nor other stones. The bridge abutment is only made of five layers of stones. The bridge foundation is very strong and the structure is simple.
1350 years ago, Li Chun dared to use such a natural foundation to bear the entire weight of the bridge. This shows that Li Chun had a profound understanding of engineering, mechanics, architecture, hydrology, geology, etc. Li Chun has so much scientific knowledge, which he undoubtedly obtained and accumulated from labor practice.
The world's tallest bridge - Millau Bridge
France has built the world's tallest bridge, towering 343 meters high among the clouds
December 11, 2004 0816
On December 9, clouds and fog in the Tarn River Valley in France passed under the Millau Viaduct.
The columns of the Millau Viaduct are 343 meters high, making it the tallest bridge in the world.
This bridge is located on the road leading from Paris, the French capital, to the Mediterranean region. Its inauguration ceremony will be held on December 14.
According to Japan's "Asahi Shimbun" report: France recently built the world's tallest bridge with a height of 343 meters in a canyon where the Taron River flows through in the Millau region in the south.
It is supported by 7 thick bridge piles and towers into the sky. It looks extremely spectacular from the photos. I don’t know whether the driver and passengers were happy to feel they were in the sky or nervous because they were afraid of falling when they passed the bridge.
It is reported that the bridge is part of the road connecting Paris and the Mediterranean coast. French President Chirac will personally attend the opening ceremony on the 14th of this month.
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Gymnastics Terminology
One of the basic terms for the bridge floor exercise movement. Refers to supporting the hands and feet, with the back of the body facing the support surface, and stretching into an arched posture as much as possible. There are bridges where one leg is supported by the other leg; bridges where one hand is supported; there are also forearm bridges, kneeling bridges, etc. Therefore bridges in other postures besides the basic bridge should be explained.