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A bridge generally refers to a structure erected on rivers, lakes and seas to enable vehicles and pedestrians to pass smoothly. In order to adapt to the modern and fast-developing transportation industry, bridges are also extended to bridges over mountain streams, unfavorable geology or other traffic needs to be erected to make traffic more convenient. Bridges are generally composed of superstructure, substructure, supports and auxiliary structures. The superstructure, also known as bridge span structure, is the main structure for crossing obstacles; the substructure includes abutments, piers and foundations; supports are span structures and piers. Or the force transmission device installed in the support space of the bridge abutment; the auxiliary structures refer to the bridge head slab, conical slope protection, bank protection, diversion works, etc. [1]
Chinese name of bridge Foreign name of Bridge Table of contents 1 Concept Definition ▪ Basic explanation ▪ Citation explanation ▪ Basic meaning 2 Historical development ▪ Ancient ▪ Modern ▪ Modern 3 Chinese History 4 Bridge categories ▪ Structural classification ▪ Length classification ▪ Other categories 5 ways to consolidate 6 Cultural connotation ▪ Extended meaning ▪ Relevant Quotes Concept Definition Editing Broadcast Basic explanation bridge Bridge (4 photos)
[Bridge] Special artificial structures with bearing capacity for railways, roads, channels, pipelines, etc. to cross rivers, valleys or other lines of communication. Road bridges. —— "Zizhi Tongjian·Tang Ji" A metaphor for a person or thing that can communicate. Pathology is a bridge course between basic and clinical. [2] Citation explanation bridge Bridge (4 photos) A building erected on water or in the air for passage. "Heguanzi·Bizhi": "There are no trails in the mountains, no bridges in the lakes, and no communication with each other." , utensils, curtains, Wu Daoxuan masters." Ming Yuan Keli "Jiazi Midsummer Climbing Office Zhonglou Guanhai Market": "It is like a cover, like a flag, like a buddha, like a puppet language, and spring trees are thousands of families. It is far and wide, bridges the state and Zhu, and there are intermittent contacts, and when the time is close, it suddenly appears and disappears. There are really painters who can't use their skills." Yang Shuo's "Kapok": "This is a long road, and travelers must You have to carry your bags and walk over the broken bridge to jump on the train on the other side." A metaphor for a person or thing that can connect and communicate. Liang Huijiao of the Southern Dynasties, "The Biography of High Monks, The Second World of Miracles, She Gong": "When you practice the good way, you will be a bridge for future generations." For example, cadres are the bridge between the party and the masses. [2] basic meaning bridge Bridge (4 photos) Bridges refer to structures constructed for roads to cross natural or artificial obstacles. The bridge is generally composed of five parts and five small parts. The five major components refer to the bridge span superstructure and substructure that bear the transportation load of automobiles or other vehicles, which are the guarantee of bridge structure safety, including: (1) bridge span structure (or bridge hole structure, superstructure); (2) bridge Support system, (3) piers, abutments; (4) caps; (5) digging wells or pile foundations. The five small parts refer to the parts directly related to the service function of the bridge, which used to be called the bridge deck structure, including: (1) bridge deck pavement; (2) waterproof and drainage system; (3) railings; (4) expansion joints; ( 5) Lighting. Auxiliary structures of large bridges also include bridgeheads and approach bridges. Historical development editing broadcast Bridges are an integral part of roads. From the perspective of engineering technology, the development of bridges can be divided into three periods: ancient, modern and modern. Ancient Nanjing Yangtze River Bridge Nanjing Yangtze River Bridge In primitive times, humans crossed waterways and canyons by using naturally fallen trees, naturally formed stone beams or stone arches, protruding stones from streams, and vines growing on valley banks. It is difficult to verify when humans purposefully cut wood for bridges or piles of rocks, and erected stones for bridges. The ancient Babylonian kingdom built multi-span wooden bridges in 1800 BC (19th century BC). According to historical records, China had already built beam bridges and wooden pontoon bridges in the Zhou Dynasty (11th century BC to 256 BC). Ancient Rome built a wooden bridge across the Tiber in 621 BC and a pontoon bridge across the Hellespont in 481 BC. In ancient Mesopotamia, stone arch bridges (soffits are stepped) were built in the 4th century BC. Before the 17th century, ancient bridges were generally built with wood and stone materials, and bridges were divided into stone bridges and wooden bridges according to the materials used to build the bridge. The main form of stone bridge is the stone arch bridge. According to textual research, stone arch bridges appeared in China during the Eastern Han Dynasty (25-220 AD). Zhaozhou Bridge (also known as Anji Bridge), built from 605 to 617 AD with a net span of 37 meters, was the first to add a lower abdominal arch to the main arch ring. The arch rings and piers of ancient Chinese stone arch bridges are generally thinner and lighter. For example, the Baodai Bridge built in AD 816-819 has a total length of 317 meters, thin piers and flat arches, and has a delicate structure. In the Roman era, many arch bridges were built in Europe. As early as 200 BC to 200 AD, 8 stone arch bridges were built on the Tiber River in Rome, among which the Fabrizio stone arch bridge was built in 62 BC. Each hole has a span of 24.4 meters. In 98 AD, Spain built the Al Bridge, which is 52 meters high. In addition, many stone arch waterway bridges have appeared, such as the existing Garde diversion bridge in France. It was built in the 1st century BC. The bridge is divided into 3 layers, the bottom layer has 7 holes, and the span is 16 to 24 meters. Most of the arch bridges in Roman times were semicircular arches with a span of less than 25 meters, and the pier was very wide, about one-third of the arch span. Hundreds of years after the fall of the Roman Empire, little progress was made in bridge building in Europe. After the 11th century, pointed arch technology was spread to Europe from the Middle East and Egypt, and pointed arch bridges began to appear in Europe. The Thames River Bridge built in the United Kingdom from 1176 to 1209 AD is a 19-hole pointed arch bridge with a span of about 7 meters. Spain built many arch bridges in the 13th century, such as the San Martin Bridge in Toledo. In addition to circular arches and cut circular arches, arch bridges also include elliptical arches and flat arches. The Pierre Bridge built in France from 1542 to 1632 AD is a seven-hole unequal-span elliptical arch with a maximum span of about 32 meters. Oval arches were all the rage at that time. From 1567 to 1569, a three-span arch bridge was built in Santa Trinita, Florence, and the ratio of the height to the span was 1:7. Bridges built in the 11th to 17th centuries had shops on both sides of the bridge deck, such as Venice, Italy. Rialto Bridge. Stone beam bridge is another form of stone bridge. Baqiao near Xi'an, Shaanxi Province, China was originally a stone beam bridge, built in the Han Dynasty, more than 2,000 years ago. In the 11th and 12th centuries AD, dozens of large stone beam bridges were built successively in the Quanzhou area of the Southern Song Dynasty, including Luoyang Bridge and Anping Bridge. Anping Bridge (Wuli Bridge) was originally 2,500 meters long and had 362 holes, but now it is 2,070 meters long and has 332 holes. Some of the existing stone bridges in Dartmoor, England, are more than 2,000 years old. bridge bridge Wooden bridges Most of the early wooden bridges were beam bridges. For example, the Wei Bridge built on the Wei River in the Qin Dynasty was a multi-span beam bridge. The span of the wooden beam bridge is not large, and the span of the outrigger wooden bridge can be increased. In the 3rd century in China, a wooden bridge with outriggers was built at the junction of Anxi, Gansu and Turpan, Xinjiang, "one hundred and fifty paces long". From 405 to 418 AD, a cantilevered wooden bridge was built at a river width of 40 zhang near Linxia, Gansu Province, and the bridge was as high as 50 zhang. The span of the splayed wooden bridge and the arched wooden bridge can also be increased. The Bassano Bridge in Italy in the 16th century was a wooden bridge. The wooden arch bridge appeared earlier. The Trayan wooden arch bridge built on the Danube in Hungary in 104 AD has a total of 21 holes, each with a span of 36 meters. The Hongqiao Bridge built by China in Kaifeng, Henan Province, with a clear span of about 20 meters, is also a wooden arch bridge. It was built in 1032 AD. The Kintai Bridge built by Japan on the Jinchuan River in Iwakuni is a five-hole wooden arch bridge. It was built around 300 AD and was built with the help of the independent Zen Master Daimangong, a Chinese monk. Bamboo cable bridges are made of bamboo strips and cables in Southwest China. The famous bamboo cable bridge is Zhupu Bridge in Guanxian County, Sichuan. The bridge has 8 holes, the maximum span is about 60 meters, and the total length is more than 330 meters. It was built before the Song Dynasty. The ancient bridge foundation was constructed by the cofferdam method in Roman times, that is, the wooden piles were driven into a cofferdam, and the bridge foundation and piers were built in it after pumping water. The British Thames Arch Bridge built in 1209 was built with the cofferdam method as its foundation. However, at that time, only manual piling and pumping were used, and the foundation was shallow. At the beginning of the 11th century in China, the famous Luoyang Bridge first threw rocks in the bridge site river, on which oysters were cultivated for two or three years and then glued to form a raft-shaped foundation, which was a pioneering work. [3] modern The production and casting of iron in the 18th century provided a new construction material for bridges. However, cast iron has poor impact resistance, low tensile properties, and is easy to break, so it is not a good bridge-building material. After the 1850s, with the development of acid converter steelmaking and open hearth steelmaking technology, steel became an important bridge-building material. Steel has high tensile strength and good impact resistance. Especially in the 1870s, steel plates and rectangular rolled section steels appeared, which created conditions for the assembly of bridge components in factories, and made steel more widely used. In the early 18th century, cement was invented by mixing and calcining lime, clay and hematite. In the 1850s, steel bars were placed in concrete to compensate for the poor tensile properties of cement. Thereafter, a reinforced concrete bridge was built in the 1870s. Modern bridge construction has promoted the rise and development of bridge science theory. In 1857, on the basis of predecessors' research on arch theory, statics and material mechanics, Saint Vernan proposed a relatively complete beam theory and torsion theory. Theories of continuous beams and cantilever beams were also established during this period. Bridge truss analyses (such as those for Warren trusses and Howe trusses) are also addressed. After the 1870s, through the efforts of German K. Kuhlmann, British W.J.M. Rankin and J.C. Maxwell and others, structural mechanics has achieved great development, which can analyze the stress of each bridge component under load. The development of these theories led to the development of trusses, continuous beams and cantilever beams. At the end of the 19th century, the theory of elastic arch has been perfected, which promoted the development of arch bridges. The rise of soil mechanics in the 1920s promoted theoretical research on bridge foundations. Modern bridges are divided according to bridge construction materials. In addition to wooden bridges and stone bridges, there are iron bridges, steel bridges, and reinforced concrete bridges. bridge bridge Wooden trusses existed before the 16th century. In 1750, several wooden bridges composed of arches and trusses were built in Switzerland, such as the Reichenau Bridge, with a span of 73 meters. From the mid-18th century to the mid-19th century, many wooden bridges were built in the United States, such as the first wooden truss bridge built over the Connecticut River in Beloz Falls, Vermont in 1785. The bridge has two spans, each 55 meters long. ; Arch and truss composite wooden bridge built over the Schuylkill River in Philadelphia in 1812 with a span of 104 meters. The truss bridge omits the arch and the diagonal bracing structure and simplifies the structure, so it is widely used. Due to the development of truss theory, various forms of truss wooden bridges have appeared one after another, such as Pratt type, Howe type, Towne type and so on. Due to the large amount of iron parts used in wooden bridges, it is not as economical to use all iron. Therefore, in the late 19th century, wooden bridges were gradually replaced by steel bridges. Iron bridges include cast iron bridges and wrought iron bridges. Cast iron is brittle, suitable for compression, not tension, and is suitable for arch bridge construction materials. The world's first cast iron bridge is the Severn River Bridge built by the Colebrookdale factory in the United Kingdom. The tensile performance of wrought iron is better than that of cast iron. In the mid-19th century, highway bridges with a span of more than 60 to 70 meters used wrought iron chain suspension bridges. The railway used truss bridges due to insufficient rigidity of suspension bridges. For example, from 1845 to 1850, Britain built the Brittany double-track railway bridge, which was a box-shaped wrought iron girder bridge. After the middle of the 19th century, the theorem and structural analysis theory of beams were successively established, which promoted the development of truss bridges, and various forms of truss beams appeared. However, at that time, the understanding of bridge wind resistance was insufficient, and bridges generally did not take wind protection measures. In December 1879, the strong wind blew down the Yangsi Taiwan Railway Wrought Iron Bridge, which was only completed 18 months ago, because the bridge did not have a horizontal continuous wind resistance structure. China built the Luding Iron Chain Suspension Bridge over the Dadu River in Sichuan in 1705. The bridge is 100 meters long and 2.8 meters wide and is still in use today. The first chain suspension bridge in Europe was the Tees River Bridge in England, built in 1741, with a span of 20 meters and a width of 0.63 meters. From 1820 to 1826, the United Kingdom built a suspension bridge with a 177-meter-long middle hole and a wrought iron eye rod in the Menai Strait in northern Wales. The bridge was rebuilt in 1940 due to lack of stiffening beams or wind-resistant structures. The world's first suspension bridge built with iron cables instead of chains is the Fribourg Bridge in Switzerland. It was built between 1830 and 1834 and has a span of 233 meters. The bridge uses 2,000 iron wires to be laid out on site, suspended from the tower, and anchored in an 18-meter-deep anchoring pit. In 1855, the United States built the Niagara Falls Road-Railway Bridge. This bridge is a suspension bridge using wrought iron cables and stiffening beams with a span of 250 meters. From 1869 to 1883, the United States built the Brooklyn Suspension Bridge in New York, with a span of 283+486+283 meters. The construction of these bridges provides the experience of using stiffeners to dampen vibrations. Since then, the long-span suspension bridges built in the United States have used stiffening beams to increase rigidity, such as the Golden Gate Bridge in San Francisco built in 1937 (the main hole is 1280 meters long, the side hole is 344 meters, and the tower height is 228 meters), and the San Francisco built in the same year. The Auckland Bay Bridge (the main hole is 704 meters long, the side hole is 354 meters, and the tower height is 152 meters) is a suspension bridge with stiffening beams. In 1940, the United States built the Tacoma Narrows Bridge in Washington State. The main span of the bridge is 853 meters, the side hole is 335 meters, the height of the stiffening beam is 2.74 meters, and the width of the bridge is 11.9 meters. On November 7 of the same year, when the wind speed was only 67.5 km/h, the middle hole and the side hole were blown down by the wind one after another. This incident prompted people to study the relationship between aerodynamics and bridge stability. Steel Bridge The Izzy Bridge over the Mississippi River in St. Louis, Missouri, USA, was built from 1867 to 1874. It was an early road and railway dual-purpose unhinged steel truss arch bridge with a span of 153+158+153 meters. When the bridge was erected, a new technology of cantilever installation was adopted. The arch ribs were suspended from both sides of the pier, pulled by the slings of the temporary wooden bents on the pier, spliced section by section, and finally connected the two half arches in the middle of the span. The foundation was sunk 33 meters into the rock layer with a pneumatic caisson. Due to the lack of safety measures in the air pressure caisson, 119 cases of severe caisson disease occurred and 14 people died. At the end of the 19th century, the theory of elastic arches was gradually perfected, which promoted the construction of large-span steel arch bridges in the 1920s and 1930s. The more famous ones are: Yuemen Bridge in New York, built in 1917, with a span of 305 meters; Bayonne Bridge in New York, It was completed in 1931 with a span of 504 meters; the Sydney Harbour Bridge in Australia was completed in 1932 with a span of 503 meters. All three bridges are double hinged steel truss arches. bridge bridge Cantilever beams designed according to mechanics appeared in the mid-19th century. The British proposed the combination of anchor span, cantilever and cantilever span based on the Tibetan wooden cantilever bridge in China, and built a railway cantilever bridge at the mouth of the Forth River in Edinburgh, England from 1882 to 1890. The bridge has a total of 6 cantilevers, the cantilever length is 206 meters, the cantilever length is 107 meters, and the main span is 519 meters long. In the early 20th century, cantilever bridges were all the rage. For example, the Queensburg Bridge in New York built in the United States from 1901 to 1909 was a bridge with an intermediate anchor span of
A bridge generally refers to a structure erected on rivers, lakes and seas to enable vehicles and pedestrians to pass smoothly. In order to adapt to the modern and fast-developing transportation industry, bridges are also extended to bridges over mountain streams, unfavorable geology or other traffic needs to be erected to make traffic more convenient. Bridges are generally composed of superstructure, substructure, supports and auxiliary structures. The superstructure, also known as bridge span structure, is the main structure for crossing obstacles; the substructure includes abutments, piers and foundations; supports are span structures and piers. Or the force transmission device installed in the support space of the bridge abutment; the auxiliary structures refer to the bridge head slab, conical slope protection, bank protection, diversion works, etc. [1]
Chinese name of bridge Foreign name of Bridge Table of contents 1 Concept Definition ▪ Basic explanation ▪ Citation explanation ▪ Basic meaning 2 Historical development ▪ Ancient ▪ Modern ▪ Modern 3 Chinese History 4 Bridge categories ▪ Structural classification ▪ Length classification ▪ Other categories 5 ways to consolidate 6 Cultural connotation ▪ Extended meaning ▪ Relevant Quotes Concept Definition Editing Broadcast Basic explanation bridge Bridge (4 photos)
[Bridge] Special artificial structures with bearing capacity for railways, roads, channels, pipelines, etc. to cross rivers, valleys or other lines of communication. Road bridges. —— "Zizhi Tongjian·Tang Ji" A metaphor for a person or thing that can communicate. Pathology is a bridge course between basic and clinical. [2] Citation explanation bridge Bridge (4 photos) A building erected on water or in the air for passage. "Heguanzi·Bizhi": "There are no trails in the mountains, no bridges in the lakes, and no communication with each other." , utensils, curtains, Wu Daoxuan masters." Ming Yuan Keli "Jiazi Midsummer Climbing Office Zhonglou Guanhai Market": "It is like a cover, like a flag, like a buddha, like a puppet language, and spring trees are thousands of families. It is far and wide, bridges the state and Zhu, and there are intermittent contacts, and when the time is close, it suddenly appears and disappears. There are really painters who can't use their skills." Yang Shuo's "Kapok": "This is a long road, and travelers must You have to carry your bags and walk over the broken bridge to jump on the train on the other side." A metaphor for a person or thing that can connect and communicate. Liang Huijiao of the Southern Dynasties, "The Biography of High Monks, The Second World of Miracles, She Gong": "When you practice the good way, you will be a bridge for future generations." For example, cadres are the bridge between the party and the masses. [2] basic meaning bridge Bridge (4 photos) Bridges refer to structures constructed for roads to cross natural or artificial obstacles. The bridge is generally composed of five parts and five small parts. The five major components refer to the bridge span superstructure and substructure that bear the transportation load of automobiles or other vehicles, which are the guarantee of bridge structure safety, including: (1) bridge span structure (or bridge hole structure, superstructure); (2) bridge Support system, (3) piers, abutments; (4) caps; (5) digging wells or pile foundations. The five small parts refer to the parts directly related to the service function of the bridge, which used to be called the bridge deck structure, including: (1) bridge deck pavement; (2) waterproof and drainage system; (3) railings; (4) expansion joints; ( 5) Lighting. Auxiliary structures of large bridges also include bridgeheads and approach bridges. Historical development editing broadcast Bridges are an integral part of roads. From the perspective of engineering technology, the development of bridges can be divided into three periods: ancient, modern and modern. Ancient Nanjing Yangtze River Bridge Nanjing Yangtze River Bridge In primitive times, humans crossed waterways and canyons by using naturally fallen trees, naturally formed stone beams or stone arches, protruding stones from streams, and vines growing on valley banks. It is difficult to verify when humans purposefully cut wood for bridges or piles of rocks, and erected stones for bridges. The ancient Babylonian kingdom built multi-span wooden bridges in 1800 BC (19th century BC). According to historical records, China had already built beam bridges and wooden pontoon bridges in the Zhou Dynasty (11th century BC to 256 BC). Ancient Rome built a wooden bridge across the Tiber in 621 BC and a pontoon bridge across the Hellespont in 481 BC. In ancient Mesopotamia, stone arch bridges (soffits are stepped) were built in the 4th century BC. Before the 17th century, ancient bridges were generally built with wood and stone materials, and bridges were divided into stone bridges and wooden bridges according to the materials used to build the bridge. The main form of stone bridge is the stone arch bridge. According to textual research, stone arch bridges appeared in China during the Eastern Han Dynasty (25-220 AD). Zhaozhou Bridge (also known as Anji Bridge), built from 605 to 617 AD with a net span of 37 meters, was the first to add a lower abdominal arch to the main arch ring. The arch rings and piers of ancient Chinese stone arch bridges are generally thinner and lighter. For example, the Baodai Bridge built in AD 816-819 has a total length of 317 meters, thin piers and flat arches, and has a delicate structure. In the Roman era, many arch bridges were built in Europe. As early as 200 BC to 200 AD, 8 stone arch bridges were built on the Tiber River in Rome, among which the Fabrizio stone arch bridge was built in 62 BC. Each hole has a span of 24.4 meters. In 98 AD, Spain built the Al Bridge, which is 52 meters high. In addition, many stone arch waterway bridges have appeared, such as the existing Garde diversion bridge in France. It was built in the 1st century BC. The bridge is divided into 3 layers, the bottom layer has 7 holes, and the span is 16 to 24 meters. Most of the arch bridges in Roman times were semicircular arches with a span of less than 25 meters, and the pier was very wide, about one-third of the arch span. Hundreds of years after the fall of the Roman Empire, little progress was made in bridge building in Europe. After the 11th century, pointed arch technology was spread to Europe from the Middle East and Egypt, and pointed arch bridges began to appear in Europe. The Thames River Bridge built in the United Kingdom from 1176 to 1209 AD is a 19-hole pointed arch bridge with a span of about 7 meters. Spain built many arch bridges in the 13th century, such as the San Martin Bridge in Toledo. In addition to circular arches and cut circular arches, arch bridges also include elliptical arches and flat arches. The Pierre Bridge built in France from 1542 to 1632 AD is a seven-hole unequal-span elliptical arch with a maximum span of about 32 meters. Oval arches were all the rage at that time. From 1567 to 1569, a three-span arch bridge was built in Santa Trinita, Florence, and the ratio of the height to the span was 1:7. Bridges built in the 11th to 17th centuries had shops on both sides of the bridge deck, such as Venice, Italy. Rialto Bridge. Stone beam bridge is another form of stone bridge. Baqiao near Xi'an, Shaanxi Province, China was originally a stone beam bridge, built in the Han Dynasty, more than 2,000 years ago. In the 11th and 12th centuries AD, dozens of large stone beam bridges were built successively in the Quanzhou area of the Southern Song Dynasty, including Luoyang Bridge and Anping Bridge. Anping Bridge (Wuli Bridge) was originally 2,500 meters long and had 362 holes, but now it is 2,070 meters long and has 332 holes. Some of the existing stone bridges in Dartmoor, England, are more than 2,000 years old. bridge bridge Wooden bridges Most of the early wooden bridges were beam bridges. For example, the Wei Bridge built on the Wei River in the Qin Dynasty was a multi-span beam bridge. The span of the wooden beam bridge is not large, and the span of the outrigger wooden bridge can be increased. In the 3rd century in China, a wooden bridge with outriggers was built at the junction of Anxi, Gansu and Turpan, Xinjiang, "one hundred and fifty paces long". From 405 to 418 AD, a cantilevered wooden bridge was built at a river width of 40 zhang near Linxia, Gansu Province, and the bridge was as high as 50 zhang. The span of the splayed wooden bridge and the arched wooden bridge can also be increased. The Bassano Bridge in Italy in the 16th century was a wooden bridge. The wooden arch bridge appeared earlier. The Trayan wooden arch bridge built on the Danube in Hungary in 104 AD has a total of 21 holes, each with a span of 36 meters. The Hongqiao Bridge built by China in Kaifeng, Henan Province, with a clear span of about 20 meters, is also a wooden arch bridge. It was built in 1032 AD. The Kintai Bridge built by Japan on the Jinchuan River in Iwakuni is a five-hole wooden arch bridge. It was built around 300 AD and was built with the help of the independent Zen Master Daimangong, a Chinese monk. Bamboo cable bridges are made of bamboo strips and cables in Southwest China. The famous bamboo cable bridge is Zhupu Bridge in Guanxian County, Sichuan. The bridge has 8 holes, the maximum span is about 60 meters, and the total length is more than 330 meters. It was built before the Song Dynasty. The ancient bridge foundation was constructed by the cofferdam method in Roman times, that is, the wooden piles were driven into a cofferdam, and the bridge foundation and piers were built in it after pumping water. The British Thames Arch Bridge built in 1209 was built with the cofferdam method as its foundation. However, at that time, only manual piling and pumping were used, and the foundation was shallow. At the beginning of the 11th century in China, the famous Luoyang Bridge first threw rocks in the bridge site river, on which oysters were cultivated for two or three years and then glued to form a raft-shaped foundation, which was a pioneering work. [3] modern The production and casting of iron in the 18th century provided a new construction material for bridges. However, cast iron has poor impact resistance, low tensile properties, and is easy to break, so it is not a good bridge-building material. After the 1850s, with the development of acid converter steelmaking and open hearth steelmaking technology, steel became an important bridge-building material. Steel has high tensile strength and good impact resistance. Especially in the 1870s, steel plates and rectangular rolled section steels appeared, which created conditions for the assembly of bridge components in factories, and made steel more widely used. In the early 18th century, cement was invented by mixing and calcining lime, clay and hematite. In the 1850s, steel bars were placed in concrete to compensate for the poor tensile properties of cement. Thereafter, a reinforced concrete bridge was built in the 1870s. Modern bridge construction has promoted the rise and development of bridge science theory. In 1857, on the basis of predecessors' research on arch theory, statics and material mechanics, Saint Vernan proposed a relatively complete beam theory and torsion theory. Theories of continuous beams and cantilever beams were also established during this period. Bridge truss analyses (such as those for Warren trusses and Howe trusses) are also addressed. After the 1870s, through the efforts of German K. Kuhlmann, British W.J.M. Rankin and J.C. Maxwell and others, structural mechanics has achieved great development, which can analyze the stress of each bridge component under load. The development of these theories led to the development of trusses, continuous beams and cantilever beams. At the end of the 19th century, the theory of elastic arch has been perfected, which promoted the development of arch bridges. The rise of soil mechanics in the 1920s promoted theoretical research on bridge foundations. Modern bridges are divided according to bridge construction materials. In addition to wooden bridges and stone bridges, there are iron bridges, steel bridges, and reinforced concrete bridges. bridge bridge Wooden trusses existed before the 16th century. In 1750, several wooden bridges composed of arches and trusses were built in Switzerland, such as the Reichenau Bridge, with a span of 73 meters. From the mid-18th century to the mid-19th century, many wooden bridges were built in the United States, such as the first wooden truss bridge built over the Connecticut River in Beloz Falls, Vermont in 1785. The bridge has two spans, each 55 meters long. ; Arch and truss composite wooden bridge built over the Schuylkill River in Philadelphia in 1812 with a span of 104 meters. The truss bridge omits the arch and the diagonal bracing structure and simplifies the structure, so it is widely used. Due to the development of truss theory, various forms of truss wooden bridges have appeared one after another, such as Pratt type, Howe type, Towne type and so on. Due to the large amount of iron parts used in wooden bridges, it is not as economical to use all iron. Therefore, in the late 19th century, wooden bridges were gradually replaced by steel bridges. Iron bridges include cast iron bridges and wrought iron bridges. Cast iron is brittle, suitable for compression, not tension, and is suitable for arch bridge construction materials. The world's first cast iron bridge is the Severn River Bridge built by the Colebrookdale factory in the United Kingdom. The tensile performance of wrought iron is better than that of cast iron. In the mid-19th century, highway bridges with a span of more than 60 to 70 meters used wrought iron chain suspension bridges. The railway used truss bridges due to insufficient rigidity of suspension bridges. For example, from 1845 to 1850, Britain built the Brittany double-track railway bridge, which was a box-shaped wrought iron girder bridge. After the middle of the 19th century, the theorem and structural analysis theory of beams were successively established, which promoted the development of truss bridges, and various forms of truss beams appeared. However, at that time, the understanding of bridge wind resistance was insufficient, and bridges generally did not take wind protection measures. In December 1879, the strong wind blew down the Yangsi Taiwan Railway Wrought Iron Bridge, which was only completed 18 months ago, because the bridge did not have a horizontal continuous wind resistance structure. China built the Luding Iron Chain Suspension Bridge over the Dadu River in Sichuan in 1705. The bridge is 100 meters long and 2.8 meters wide and is still in use today. The first chain suspension bridge in Europe was the Tees River Bridge in England, built in 1741, with a span of 20 meters and a width of 0.63 meters. From 1820 to 1826, the United Kingdom built a suspension bridge with a 177-meter-long middle hole and a wrought iron eye rod in the Menai Strait in northern Wales. The bridge was rebuilt in 1940 due to lack of stiffening beams or wind-resistant structures. The world's first suspension bridge built with iron cables instead of chains is the Fribourg Bridge in Switzerland. It was built between 1830 and 1834 and has a span of 233 meters. The bridge uses 2,000 iron wires to be laid out on site, suspended from the tower, and anchored in an 18-meter-deep anchoring pit. In 1855, the United States built the Niagara Falls Road-Railway Bridge. This bridge is a suspension bridge using wrought iron cables and stiffening beams with a span of 250 meters. From 1869 to 1883, the United States built the Brooklyn Suspension Bridge in New York, with a span of 283+486+283 meters. The construction of these bridges provides the experience of using stiffeners to dampen vibrations. Since then, the long-span suspension bridges built in the United States have used stiffening beams to increase rigidity, such as the Golden Gate Bridge in San Francisco built in 1937 (the main hole is 1280 meters long, the side hole is 344 meters, and the tower height is 228 meters), and the San Francisco built in the same year. The Auckland Bay Bridge (the main hole is 704 meters long, the side hole is 354 meters, and the tower height is 152 meters) is a suspension bridge with stiffening beams. In 1940, the United States built the Tacoma Narrows Bridge in Washington State. The main span of the bridge is 853 meters, the side hole is 335 meters, the height of the stiffening beam is 2.74 meters, and the width of the bridge is 11.9 meters. On November 7 of the same year, when the wind speed was only 67.5 km/h, the middle hole and the side hole were blown down by the wind one after another. This incident prompted people to study the relationship between aerodynamics and bridge stability. Steel Bridge The Izzy Bridge over the Mississippi River in St. Louis, Missouri, USA, was built from 1867 to 1874. It was an early road and railway dual-purpose unhinged steel truss arch bridge with a span of 153+158+153 meters. When the bridge was erected, a new technology of cantilever installation was adopted. The arch ribs were suspended from both sides of the pier, pulled by the slings of the temporary wooden bents on the pier, spliced section by section, and finally connected the two half arches in the middle of the span. The foundation was sunk 33 meters into the rock layer with a pneumatic caisson. Due to the lack of safety measures in the air pressure caisson, 119 cases of severe caisson disease occurred and 14 people died. At the end of the 19th century, the theory of elastic arches was gradually perfected, which promoted the construction of large-span steel arch bridges in the 1920s and 1930s. The more famous ones are: Yuemen Bridge in New York, built in 1917, with a span of 305 meters; Bayonne Bridge in New York, It was completed in 1931 with a span of 504 meters; the Sydney Harbour Bridge in Australia was completed in 1932 with a span of 503 meters. All three bridges are double hinged steel truss arches. bridge bridge Cantilever beams designed according to mechanics appeared in the mid-19th century. The British proposed the combination of anchor span, cantilever and cantilever span based on the Tibetan wooden cantilever bridge in China, and built a railway cantilever bridge at the mouth of the Forth River in Edinburgh, England from 1882 to 1890. The bridge has a total of 6 cantilevers, the cantilever length is 206 meters, the cantilever length is 107 meters, and the main span is 519 meters long. In the early 20th century, cantilever bridges were all the rage. For example, the Queensburg Bridge in New York built in the United States from 1901 to 1909 was a bridge with an intermediate anchor span of
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