How to determine the lowest elevation of bridge deck

Bridge Engineering Papers-Star Journals-Netease Blog

Bridge engineering paper, Netease Star Blog, when you are not by my side, I will let the memories stay with me.

Blog. 163. com/ Wuxing forever/blog/static/12 ... 2010-1-6-Baidu snapshot

Road and Bridge Engineering Papers _ Baidu Know

I am a secondary school student, and I am about to graduate. Please help me pass on some graduation papers on roads and bridges, and I will learn from them ... Combined with engineering examples, this paper analyzes the high-pressure jet grouting pile from three aspects: working mechanism, construction technology and quality inspection. ...

zhidao.baidu.com/question/ 14 1 187529.html 20 10-3-9

-

Development Foundation of Bridge Engineering —— Development of Materials and Technology

Abstract: The rapid development of engineering materials and technology often promotes the rapid development of bridge engineering.

Keywords: engineering materials, engineering technology to promote the development of bridge engineering

With the progress of science and technology and the development of engineering practice, the discipline of civil engineering has also developed into a comprehensive system with wide connotation, numerous categories and complex structure. For example, as far as the functions of engineering facilities built by civil engineering are concerned, some of them are used for living and even as "buried underground" graves; Some are used as places for production activities; Some are used for land, sea and air transportation; Some are used for water conservancy; Some are used as tools for information transmission; Some are used as a means of energy transfer and so on. This requires that civil engineering should make comprehensive use of various material conditions to meet various needs. Civil engineering has developed many branches, such as housing engineering, railway engineering, road engineering, airport engineering, bridge engineering, tunnel and underground engineering, special engineering structure, water supply and drainage engineering, urban heating and gas supply engineering, port engineering, water conservancy engineering and other disciplines. . This semester, we studied "Introduction to Civil Engineering" and learned a lot about our major. I am personally interested in bridge engineering:

The development of bridge engineering mainly depends on the needs of transportation. The ancient bridge is dominated by people and animals, with little load. The longitudinal slope of the bridge deck can be steep, and even steps can be laid. With the heavy-duty carriage, the load will gradually increase, and the longitudinal slope of the bridge deck must also be gentle. At this time, the bridge materials are still mainly wood and stone, and cast iron and wrought iron are rarely used.

From the initial prototype of the bridge-dike beam (and stone dikes built in shallow streams, flowing water between dikes and people crossing over the stone dikes), single-plank bridges, pontoons (bridges erected on ships) and stone arches, to suspension bridges with a span of more than 1,000 meters, the development of bridge engineering can be described as earth-shaking for thousands of years. However, the earth-shaking development of bridge engineering depends on the strong promotion of the rapid development of engineering materials and engineering technology. In primitive society, ignorant ancient humans only pursued a cave to get up and fill their stomachs with food, without thinking of bridges. However, with the development of society, the progress of human civilization and the continuous development of transportation, people began to create bridges. But at that time, the use of engineering materials was limited to natural wood and stone, and the engineering technology was very backward. People could only build simple bridges-pier beams, wooden bridges and simple stone arches. The oldest stone bridge in the world is located in the Peloponnesian Peninsula of Greece. It is a single-hole stone arch bridge with a stone base, which was built about 3500 years ago. The development of ancient bridge engineering technology in China was in the leading position in the world at that time. Zhao Zhouqiao is a single-hole stone arch bridge with open shoulders in Sui Dynasty, which was built between 590 and 608, and is located on the Zhao River in Hebei Province. The total length of the bridge is 50.82m, and the bridge deck width is about 10m, which is made of 28 parallel stone bars. Arch tickets are 7.23 meters high. There are four small arches on the arch, which can not only reduce the weight of the bridge, but also facilitate flood discharge and make it more beautiful. This bridge has achieved great success in material use, structural stress, artistic modeling and economy. It is the earliest open-shouldered arch bridge in the world, about 65,438+0,000 years earlier than similar bridges in Europe. The time span of modern civil engineering is1300 years from the middle of the 7th century to the middle of the 20th century. The main characteristics of civil engineering in this period are:-under the guidance of mechanics and structural theory; -Brick, tile, wood, stone and other structural building materials are widely used; Concrete, steel, reinforced concrete and early prestressed concrete have all developed; -Great progress has been made in construction technology, the scale of construction is expanding day by day, and the construction speed is greatly accelerated. During this period, the following major events have a significant impact on bridge engineering:

(1) In the book Talks and Mathematical Proof of Two New Sciences published in 1638, Italian scholar Galileo discussed the mechanical properties of building materials and the strength of beams, and expressed the design theory of beams with formulas for the first time.

(2) Newton, a British scientist, summed up three laws of mechanics in 1687, which are the basis of civil engineering design theory.

(3) The curve variational method published by Swiss mathematician Euler 1744 establishes the buckling theory of columns and obtains the formula for calculating the critical stress of columns, which lays a foundation for analyzing the stability of civil engineering structures.

(4) 1824, British asp Ding obtained the patent right of portland cement, and it was put into production in 1850. This is the main material to form concrete, which makes concrete widely used in civil engineering. Later, at the beginning of the 20th century, someone published the theory of water-cement ratio, which initially laid the theoretical foundation of concrete strength.

(5) 1859, Bessemer converter steelmaking method was invented, and similar steel products were produced in large quantities and more and more used in civil engineering.

(6) 1867, monineath, a Frenchman, made a flowerpot with iron wire reinforced concrete, and applied this method to the construction of a reservoir, which was the beginning of the application of reinforced concrete. 1875 presided over the construction of the first reinforced concrete bridge with a length of 16m.

(8) 1779, an arch bridge with a span of 30.5m was built in Britain with cast iron; 1826, a suspension bridge with a span of 177m was built in Britain with forged iron; 1883, the United States built the world's first long-span steel suspension bridge-Brooklyn Bridge; 1890, a cantilever rigid frame bridge with two main spans of 52 1m was built in Britain. In this way, three basic forms of modern bridges (beam bridge, arch bridge and suspension bridge) have appeared one after another.

Since the establishment of the railway, the load borne by the bridge has doubled, and the standard requirements of the slope and curve of the line are high. It is necessary to build a railway network to increase economic benefits. Therefore, in order to cross larger and deeper rivers and canyons, bridges are forced to develop in large spans. Stone, wood, cast iron, wrought iron and other bridge materials obviously do not meet the requirements, and the mass production of steel just meets this requirement.

In terms of technology, repairing bridges only by experience has caused many serious accidents of railway bridges in the 1980s and 1990s of 19. Since then, the developing theory of structural mechanics has been paid attention to. After its static analysis theory was completely established and widely popularized, the accidents caused by the lack of bridge strength have been greatly reduced.

Since the 20th century, highway traffic has developed greatly. Inland, it is necessary to build bridges over more rivers and canyons. In the city, at the intersection of various traffic lines, it is necessary to build overpasses. In coastal areas, it is necessary to build extra-long-span bridges in estuaries, bays and straits where large ships can sail, and to build long bridges between some islands and the mainland.

Due to the emergence of more new technologies and materials, modern bridge engineering has developed rapidly, and countries all over the world have built bridges over 1,000 meters. Lunabarios Bridge in Spain, the largest prestressed concrete cable-stayed bridge in the world, has a span of 440m and is arranged with double-sided radiation cables. The world's first suspension bridge, Akashi Strait Bridge in Japan, spans the internal sea of Japan and connects Kobe, Japan, with Awaji Island. The total length of the bridge is 365,438+090 meters, of which the span of 1990 meters was completed in 1998. It can withstand an earthquake measuring 8.5 on the Richter scale. At present, a number of highway bridges under construction in China represent the advanced level in the world and have created the history of bridge construction in China, regardless of the number of bridges, project scale, technical difficulty or scientific and technological content. It is reported that these bridges mainly include: Yangluo Yangtze River Bridge, suspension bridge with main span of 1280 meters; Nanjing Yangtze River Third Bridge, a cable-stayed bridge with a main span of 648 meters; Runyang Yangtze River Highway Bridge, a suspension bridge with a main span of 1490 m and a cable-stayed bridge with a span of 406 m across Jianglian Island; Shenzhen Bay Cross-sea Bridge, a single tower and single cable plane cable-stayed bridge with a main span of 180m; Sutong Yangtze River Highway Bridge, cable-stayed bridge, main span1088m, ranking first in the world; Hangzhou Bay Bridge, built according to the standard of two-way six-lane expressway, is the longest highway bridge under construction in the world, with a total length of 36 kilometers. It is rare in the world for a country to build so many world-class bridges at the same time.

Bridges need to be built in large quantities, but manpower, material resources and financial resources are limited; Therefore, it has become the requirement of the times to continuously improve the technical level, introduce new materials, new processes and new bridges, conduct more accurate numerical analysis of structural behavior and use more accurate structural tests for verification, so as to continuously improve the economic benefits of bridge construction.

Bridge engineering mainly studies the design of bridge span, including the selection of bridge site, the determination of bridge aperture, the determination of deck elevation considering navigation and line requirements, the determination of foundation buried depth considering no scouring or frost heaving, and the design of diversion buildings. Bridge scheme design; Bridge structural design; Bridge construction; Bridge grade; Bridge testing; Bridge maintenance and so on.

In terms of bridge building materials, high strength, light weight and low cost are the main basis for selection. In the near future, traditional steel and concrete are still the main materials to improve their strength and durability. Brittle fracture mechanism of building steel, initial geometric defects and inelastic problems of concrete materials (shrinkage, creep and fatigue, etc.). ) will continue to fully study, so as to correctly control the stress and deformation of the structure. As for the wide application of carbon fiber plastics in bridges, it is only possible after reducing the cost.

In bridge survey and design, with the rapid development of transportation, long-span or complex bridge types will appear continuously. The development of expressway will also put forward new requirements for bridge design. In bridge scheme design, we can use the theory of structural optimization design and choose the best scheme with the help of computer.

In structural design and calculation, it is possible to analyze the overall stress of bridges by using space theory. The limit state design theory based on probability and statistics theory will be further embodied in the design code of bridges and culverts, thus ensuring the safety of bridge design scientifically and reasonably. As a reflection of the times and national culture in some aspects, bridge aesthetics will be paid more and more attention: the face of the bridge will be magnificent.

In bridge construction, the construction organization will make full use of computers for economic and effective management. In terms of construction technology, new technologies and high-efficiency and high-performance mechanical equipment are constantly introduced to improve quality, shorten construction period and reduce costs. For example, laser measurement is used to control the precise positioning of structures; Using jack-up water platform to overcome the difficulties of deep water foundation; Using remote control equipment to excavate the foundation in open caisson and caisson, so as to reduce labor intensity and avoid personal danger; By using high-quality welding technology, Site welding and others can be popularized. In addition, prefabricated bridges will be developed to realize the standardization and industrial production of structures and components.

In the aspect of bridge maintenance, it is required to establish a perfect management system of existing bridge technical files. In bridge maintenance inspection, new precision measuring instruments, such as acoustic measurement, are introduced to measure the defects and elastic modulus of structural materials; Check the crystal structure of steel with hand-held metallographic camera, so as to reinforce it as early as possible, prevent problems before they happen, and thus prolong the service life of the bridge.

Under the comprehensive influence of production development and all kinds of scientific and technological progress, bridge engineering has always been developing continuously, following the principles of applicability, safety, economy and beauty. People not only require the perfect function of the bridge, but also emphasize the beauty and artistry of the bridge appearance. The construction of bridges will be more complicated and artistic, and the future of bridges will be more diversified. Whether the modern bridge is more modern or the old bridge is revived is worth looking forward to!

The history of Chinese bridges can be traced back to the clan commune era 6000 years ago, and the development of ancient bridges reached its peak in the Sui, Tang and Song San periods 1000 years ago. In 35 AD, during the reign of Emperor Guangwu of the Eastern Han Dynasty, the first pontoon bridge on the Yangtze River appeared between Yichang and Yidu.

During the Qin and Han Dynasties, Liang Shi Bridge was widely built in China. At present, the longest and most arduous Liang Shi Bridge in the world, namely Wan 'an Bridge, also known as Luoyang Bridge, was built in 1053- 1059 Quanzhou, Fujian. The bridge is 800 meters long and has 47 holes. It is located on the Haikou River, which is "rough and deep". This bridge is paved with rocks at the bottom of the bridge site, which is the beginning of modern mat foundation. The bridge foundation is glued into a whole by cultivating marine oysters, which is also a unique bridge-building method in the world. It is a brave breakthrough in the history of Chinese bridges to build such a long bridge under such difficult and complicated hydrological conditions nearly a thousand years ago.

The outstanding representative of ancient stone arch bridge in China is the world-famous Zhao Zhouqiao (also known as Anji Bridge) in Zhao County, Hebei Province. This bridge was built by Li Chun in the early years of the great cause of Sui Dynasty (around 605 AD). The hollow circular stone arch bridge has a clear span of 37m, a width of 9m and a height of 7.23m There are two abdominal arches with different spans on both sides of the arch ring, which can not only reduce the dead weight of the bridge, save materials, but also facilitate the layout. Zhao Zhouqiao's design concept and exquisite craftsmanship are not only second to none among ancient bridges in China. According to the research of bridges in the world, open-shouldered arch bridges like this didn't appear in Europe until the middle of the 9th century, which was more than 200 years later than China. Zhao Zhouqiao's carving art, including railings, watchposts and lock stones, lions, dragons and animals are lifelike in shape and exquisite in craftsmanship, which is worthy of being regarded as an artistic treasure in the treasure house of cultural relics, and it is in the construction of stone arch bridge in China.

The Hudu Bridge in Tanzhou, Fujian Province, built at 1240, is also the most amazing beam bridge. The total length of this bridge is about 335m, and the length of some Liang Shi is 23.7m m. It is composed of three Liang Shi along the width direction, each Liang Shi is 1.7 m wide and 1.9 m high, weighing more than 200 tons. This bridge has been preserved to this day.

Xiangzi Bridge (also known as Guangji Bridge) across the Han River in Chaoan County, Guangdong Province, was built in 1 169, with a total length of 5 17.95m and a total of ***20 piers and 19 holes. Superstructures include stone arches, wooden beams, Liang Shi and other types, with 65,438. On the one hand, it is suitable for the passage of large merchant ships and upstream rafts, and it also avoids too many piers blocking the river course, aggravating the erosion of the bridge foundation and causing water damage. This world's earliest open-close bridge is rare in the history of ancient bridge construction because of its long column stone bridges, large stone piers, numerous bridges and difficult construction conditions. . 1957, the first Yangtze River Bridge, Wuhan Yangtze River Bridge, was successfully completed, ending the situation that there was no bridge on the Yangtze River in China. From then on, "a bridge flies north and south, and the natural barrier becomes a thoroughfare." The main bridge of the bridge is a triple continuous steel truss beam with a width of 3X 128m, and there are 2.25m sidewalks on both sides of the upper highway of the double-track railway.

1969, the world-famous Nanjing Yangtze River Bridge was successfully completed. This is a modern large-scale bridge designed, manufactured and constructed by our country and built with domestic high-strength steel. Except that the first hole on the north bank of the bridge is a simply supported steel truss of 128m, all the others are 9 holes and 3 joints, each joint is a 3x l60m continuous steel truss. The upper floor is a highway bridge, and the lower floor is a double-track railway. Including the approach bridge, the total length of the railway section is 6772m, and the highway section is 4589 m. The water depth of the bridge is turbulent, the riverbed and water quality are extremely complicated, and the construction of pier foundation is very difficult. The completion of Nanjing Yangtze River Bridge marks that China's bridge construction has reached the advanced level in the world, and it is also an important milestone in the history of Chinese bridges.

Recently 1000, China's bridge technology has fallen behind the pace of the world. The first modern bridge in China is only 100 years old and was built by foreigners. Since Qiantang River Bridge, China people have designed modern bridges for less than 70 years. From the Nanjing Yangtze River Bridge, the history of designing and building large bridges in China is only 34 years.

Since the 1990s, the achievements of Chinese bridges have made us stand in the forefront of the world again, which is a great rejuvenation era of Chinese bridge construction. Over the past 20 years of reform and opening up, China has made remarkable achievements in bridge construction technology. In the first decade, it made economic, technical and talent preparations for this, and in the 1990s, it ushered in a leap-forward development. Looking forward to the future, with the economic development of China and the construction of a number of larger cross-river and cross-sea projects, Chinese bridges will create more brilliant achievements. The great rejuvenation of the Chinese nation will certainly create a generation of giants and lead the future of the bridge of the world.

Xiaonanmen Bridge built in Yibin City, Sichuan Province from 65438 to 0990, with a span of 240 meters, was the largest half-through arch bridge in the world at that time. On 200 1, 1 1 year1October 7th, part of the bridge deck of Xiaonanmen Bridge collapsed due to corrosion of suspenders. During the repair process, technicians inspected the whole bridge, and the overall structure of the bridge was still intact. The price of Xiaonanmen Bridge is the price of innovation. Without innovation, we would not have seen Zhao Zhouqiao 400 years ago.

199 1 year, the first concrete-filled steel tubular arch bridge in China was built in Cangxi county, Sichuan province, with a span of115m. In the following years, although many concrete filled steel tubular arch bridges were built in various places, the span was always below 200 meters. Until 1998, the Yongjiang Bridge with three banks was built in Guangxi Zhuang Autonomous Region, which increased the span of such bridges to 270 meters in one fell swoop. 1999, Liu Jing Bridge with a span of 220m was completed. Since then, in Hubei, Zhejiang, Guizhou and other provinces, concrete-filled steel tubular highway and railway arch bridges with a span of about 250 meters have begun to increase.

1995, Jiangjiehe Bridge in Weng 'an County, Guizhou Province was completed, which broke through the 300-meter mark of China concrete arch bridge for the first time and reached 330 meters, making it the largest truss composite arch bridge in the world. And the height from the arch bridge surface to the water surface is 263 meters, ranking first among all kinds of bridges in China. The bridge crossed the Wujiang River as soon as it crossed. The main tunnel is prefabricated with 108 truss, which is erected by cantilever truss method. The approach bridges on both sides of the bridge are truss rigid frames. The whole bridge is light and simple, flying in the air with extraordinary momentum.

1997 completion of Wanxian Yangtze River Bridge in Chongqing. The bridge is located in Huangniukong, Wanzhou District (formerly Wanxian City), and it is a super-large arch bridge across Xiajiang natural barrier on Shanghai-Chengdu Expressway. The bridge spans the Yangtze River with a total length of 856.12m. The main arch ring is a box-shaped concrete structure with a rigid skeleton of concrete filled steel tube, with a main span of 420 meters and a bridge deck width of 24 meters. As a two-way four-lane bridge, it was built in Weng 'an County, Guizhou Province on 1995. For the first time, it broke through the 300m mark of China concrete arch bridge, reaching 330m, becoming the largest truss in the world. And the height from the arch bridge surface to the water surface is 263 meters, ranking first among all kinds of bridges in China. The bridge crossed the Wujiang River as soon as it crossed. The main tunnel is prefabricated with 108 truss, which is erected by cantilever truss method. The approach bridges on both sides of the bridge are truss rigid frames. The whole bridge is light and simple, flying in the air with extraordinary momentum.

Jiangyin Yangtze River Highway Bridge, the first bridge in China, is a river-crossing project of the coastal skeleton in the "two vertical and two horizontal" national trunk line of the Eighth Five-Year Plan of China. It is the first steel suspension bridge in China and the fourth longest suspension bridge in the world. The bridge is composed of tower, main cable, anchor, steel box girder and other main components. The total length of the bridge is 307 1 m and the main span is 1385 m. The bridge deck is 33.8 meters wide, with six lanes in both directions, and the design speed is100 km/h; The navigation clearance is 50 meters, and it can pass 50,000 tons of Panamanian bulk carriers. The two main cables of Jiangyin Yangtze River Highway Bridge are more than 2,400 meters long, with a diameter of nearly 1 meter, and each cable weighs more than 1.4 million tons. The main cable is made of 127 steel wire with a diameter of 5.3 mm, and then composed of 169 steel wire. There are 85 suspenders on both sides of the main bridge, of which 2 suspenders are used to connect the main cable and the bridge deck. The elevation of pylon on both banks is196.236m, which is equivalent to the height of 65 stories. The foundation of the North Tower is 43.5 meters long and 73.5 meters wide, with 123 piles nearly 90 meters long. The concrete plane of the North Anchor is 69 meters long and 5 1 meter wide (the area is equivalent to a football field). It sank 58 meters underground and is known as the largest open caisson in the world. Jiangyin Yangtze River Bridge was officially started on 1 October 22nd 1994, 165438,1October 22nd 1999,1,ranking "the first in China and the fourth in the world".

Over the past 20 years of reform and opening up, China has made remarkable achievements in bridge construction technology. In the first decade, it made economic, technical and talent preparations for this, and in the 1990s, it ushered in a leap-forward development. Looking forward to the future, with the economic development of China and the construction of a number of larger cross-river and cross-sea projects, Chinese bridges will create more brilliant achievements. The great rejuvenation of the Chinese nation will certainly create a generation of giants and lead the future of the bridge of the world.

1. Luo. Introduction to civil engineering. Wuhan University of Technology Press

2. Yang Jing. Building materials. China Water Conservancy and Hydropower Press. 2004,2

3. Sheng Editor-in-Chief "Bridge"

4 Luo Ying: China Shiqiao People's Communications Publishing House 1959.

5 Mao Yisheng: Technical History of Ancient Bridges in China Beijing Publishing House 1986.

6 Tang Huancheng: China Ancient Bridge Beijing Cultural Relics Publishing House 1957.