That we should build a bridge. British Army Pontoon Bridges and Ferries

Clapper

Opening our list is an ancient form in which large flat stone slabs rest on piles of stones. Most of them were built in the Middle Ages to create a path across a river or other obstacle.

An excellent example of this type is the Postbridge, built over the East Dart River in the English county of Devon. Its slabs are more than 4 m long, and each slab weighs more than 8 tons. It was built in the 13th century to allow horses to cross the river, delivering tin to the famous town of Tavistock.

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Bridge architecture

A bridge is an artificial structure erected across a river, lake, swamp, ravine, strait or any other physical obstacle. A bridge built across a road is called an overpass, a bridge over a ravine or gorge is called a viaduct. The bridge is one of the oldest engineering inventions of mankind. As a rule, bridges consist of spans and supports. Superstructures serve to absorb loads and transfer them to supports; they may contain a roadway, a pedestrian crossing, or a pipeline. The supports transfer loads from the spans to the base of the bridge. Span structures consist of load-bearing structures: beams, trusses, diaphragms (transverse beams) and the roadway slab itself. The static design of spans can be arched, beamed, framed, cable-stayed or combined; it determines the type of bridge by design. Typically, span structures are rectilinear, but if necessary (for example, when constructing overpasses and road junctions), they are given a complex shape: spiral-shaped, circular, etc. The span structures are supported by supports, each of which consists of a foundation and a supporting part. The shapes of supports can be very diverse. Intermediate supports are called bulls, coastal ones are called abutments. The abutments serve to connect the bridge with the approach embankments. The materials for bridges are metal (steel and aluminum alloys), reinforced concrete, concrete, natural stone, wood, and ropes.

I present the designs of a wide variety of bridges built during different periods of human existence in different countries.

Devil's Bridge is an architectural monument located at an altitude of 400 meters above sea level in the eastern part of the Rhodope Mountains in Southern Bulgaria, one of the attractions of the Eastern Rhodope Mountains. The bridge was built in the 16th century on the site of an ancient Roman bridge on the road that connected the Mountain Thracian lowland with the Aegean coast. The length of the bridge is 56 m, width is 3.5 m.

Currently, the bridge is not in use and is protected as a cultural monument. Many legends surround this bridge. Some believe that in one of its stones the imprint of the Devil’s foot is visible, and the place itself brings misfortune and death to those who dare to approach it. Others believe that Satan saved one Bulgarian girl from death by appearing before the Turkish horsemen who were pursuing her to take her into captivity. The girl was ready to commit suicide by throwing herself from the bridge, but when she reached it, the Turks who were pursuing her suddenly turned back, seeing a horned head in the water under the bridge.

And the most common legend says that the master walled up the shadow of a girl in the bridge, who brought him food while working on the bridge, thereby dooming the structure to stability in time, and the girl herself to death (according to Bulgarian folklore, if the shadow is walled up, then the person begins to melt and soon leaves the world of the living)

Local residents tried for years to build a bridge between the two banks, but each time the stormy waters of the Arda River destroyed the structure. And when, in despair, they had already abandoned the idea of ​​​​building a bridge, a young master unexpectedly took up the matter. The Devil unexpectedly appeared to him and revealed to the master the secret of building a stable bridge. But he set a condition: the face of Satan should be visible in the design, which should be both visible and invisible, which could be touched, but at the same time the face should not materialize. And the master decided to sacrifice the life of his beloved (by walling up her shadow) in order to build a bridge. Satan gave the craftsman 40 days to complete the construction. Otherwise, the Devil threatened to take the souls of the master and his beloved. To everyone's surprise, the master fulfilled all the Devil's conditions. But soon after that he died and his mystery turned out to be unsolved

The secret, which is both visible and not, which can be touched but cannot be materialized, is located exactly under the central arch and is a rock. The image of the devil is, as it were, carved on this rock, but halfway. The other half is reflected in the water. At the same time, the arch of the bridge is also reflected in the water, forming a circle. The image of the Devil is visible only at that moment of the day (approximately between 11.00 and 12.00 hours) when the position and strength of the sun are such that the bridge and its reflection in the water coincide completely.

The Devil's Bridge has stood for 500 years and shows no signs of collapsing.

Bridges that can safely be called masterpieces of architecture

10 most difficult bridges

In the new millennium, bridges still connect point A to point B, but every architect strives to solve this simple problem in the most complex way.

1. Bridge over the Haihe River, Tianjin, China, architect Marc Mimram French architect Marc Mimram erected a three-span bridge of an unusual design in one of the main Chinese industrial centers in the city of Tianjin. The arched pipes are connected to each other by steel “petals”, which are located at different angles and reflect sunlight during the day, and are illuminated by lamps at night. So the bridge shines at any time of the day and serves as the main city landmark.

2. Island on the Mur River, Graz, Austria, architect Vito Acconci An artificial island in the middle of the river dividing the Austrian town of Graz is a real PR project. In an effort to draw attention to his hometown, businessman Robert Punkenhofer invited New York architect Vito Acconci to build a bridge with a theater in the middle. And then Graz was declared the European Capital of Culture 2003.

3. Bridge in Enschede, the Netherlands, architectural bureau Next Architects “Do no harm!” - the motto of not only doctors, but also architects from the Dutch bureau Next. In the suburb of Enschede they built a bridge that can serve as an example of “green architecture”. Its supports are made of local stones, and over time grass should grow through them. In addition, the risk of accidents is minimized: lanes for pedestrians, cyclists and cars are located at different heights.

4. Observation deck over the Aurland fjord, Norway, architectural bureau Saunders Architecture When Canadian Todd Saunders was entrusted with the construction of an observation deck over the largest Norwegian fjord, it turned out that the best view opens thirty meters beyond the edge of the cliff. Therefore, he had to build a structure over it that resembled a diving tower. And to prevent unwary onlookers from falling down, a glass barrier was installed at the end.

5. Transition to Frolar Street, London, Wilkinson Eyre Architects Redevelopment of historic houses is prohibited in England. Therefore, to create a passage between Covent Garden and the Royal Ballet School, the architects used an existing window opening of the neoclassical opera house and connected it to the superstructure above the school. And so that the height difference from below was not noticeable, a spiral design was used.

6. Arch Bridge in Glasgow, UK, architectural bureau Halcrow Group In the short life of this bridge over the Scottish River Clyde there were tragic episodes. A couple of months after the grand opening, one of the cables that held the entire structure broke off and fell into the water. After this, the bridge was closed to traffic, leaving only pedestrian parts. The creators had to seek a verdict from a special commission, which confirmed that all other supports were safe and the bridge would last for at least another hundred and twenty years.

7. Bridge - Sundial, Redding, USA, architect Santiago Calatrava There are not many places on the planet where you can see the passage of time with your own eyes. One of them is located in California - here the architect Santiago Calatrava built a cable-stayed bridge across the Sacramento River. Its single 66-meter support also serves as the hand of a huge sundial. The shadow from its upper part moves along the dial drawn around the bridge by thirty centimeters every minute.

8. Pedestrian bridge in Seattle, USA, architectural bureau Johnson Architecture Biotechnology corporation Amgen decided to celebrate the opening of its office in Seattle on a grand scale. They sponsored the construction of a new pedestrian bridge over the railroad tracks and at the same time erected a monument to their developments. The bridge rests on three arches located at an angle, and a steel mesh of complex design connects them. The result is a structure similar to a DNA molecule - the main subject of Amgen's research.

9. Donghai Bridge in Shanghai, design bureau China Zhongtie Major Bridge Engineering Group The world's largest sea bridge is, of course, in China. It is 32.5 km long and connects Shanghai with the nearest deep-sea port of Yangshan. And so that ships with a shallow landing can still enter the city harbor, there is an adjustable part on cables in the middle.

10. Rolling Bridge, London, Heatherwick Studio On weekends, the bridge over the Grand Union Canal is not much different from any other. But on weekdays it looks more like a minimalist sculpture. The creators used hydraulic ram technology, which has been used in fountains since the 18th century, so that the “twisting” of the bridge occurs with the help of water. It is pumped under pressure into pipes hidden between the sections, and the railings, folding in half, collapse the entire structure.

Text: Anastasia Uglik

Source: https://www.admagazine.ru/arch/49424_10-samykh-slozhnykh-mostov.php

Truss

Instead of one beam having to withstand all the forces, a series of beams and trusses are used. A truss is a triangular frame that distributes tensile and compressive forces across the bridge.

There are several ways to build a truss bridge, but they all have the same goal: to distribute tension and compression forces so that the structure does not collapse. The truss gives stability to the entire structure, capable of withstanding large external loads over a long span.

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The longest bridges in the world: how they are built and why they are known throughout the world

Any bridge construction begins with a comprehensive geodetic study. Engineers try to choose the narrowest point of the river or artificially reduce the distance between the banks using an embankment, if possible. To prevent this from interfering with the natural flow of water, workers deepen the river bed using dredgers. To build supports, shallows are usually used, which are additionally sprinkled with soil, thus creating artificial islands.

How are bridges built?

The end supports of bridges are erected directly from the banks of rivers, using part of the land for this. Problems begin when supports need to be erected in the middle of a deep river, bay, lake or sea. These intermediate supports, which are the most difficult to build, are called “bulls.” There are several ways to install them.

Larsen tongue and groove

You can drain the site where the supports are being built by changing the river bed. If a bridge is laid across a bay or lake, then builders drive piles for supports from the side of a special pontoon or vessel.

To do this, a waterproof frame is first created in the construction area from special Larsen tongue-and-groove sheets. Then it is specially reinforced from the inside, and water is pumped out of the structure and piles are driven in along the contour. After immersion to the required depth, the piles are “fluffed” from above and then tied with a grillage. This is the lattice part that connects the top of the pile foundation. Subsequently, the structure is filled with concrete, and only then reinforced concrete supports are erected on top.

Driven piles

When building foundation elements underwater, driven piles allow crews to create strong structures without having to remove water altogether. Piles, which look like long vertical columns, can be driven into the ground using a powerful hammer, creating a stable foundation for underwater or above-water structures.

In underwater construction, steel piles are most often used, but there are voids inside them. After the piles are driven in, their interior is filled with concrete, which displaces water from the cavities. This method of underwater construction is one of the most economical.

Interestingly, all of these methods have the same basic goal: to avoid building underwater. Instead, water is diverted or avoided in various ways during construction. So, building underwater is more about finding creative ways to bypass water and create structures that can withstand it once construction is complete.

Caissons

And finally, the third method is the construction of supports using closed (underwater) caissons. This method of constructing foundations is also called pneumatic.

Caissons are waterproof structures that can be submerged in water while maintaining a dry environment inside. Inside the dry space of an open caisson, workers can dig down to reach a solid surface on which the caisson will rest. Eventually, the caissons become part of the foundation of a structure, often a bridge or dam.

The caissons have special sluices through which soil is removed and materials for concreting the supports are introduced. By digging the bottom under the edges of the caisson from the inside, builders gradually deepen the structure until they reach a solid layer that can serve as a reliable base for the future structure.

The longest bridges in the world

According to Encyclopedia Britannica, the longest bridge in the world is the Danyang-Kunshan Grand Bridge in China, part of the Beijing-Shanghai high-speed railway. It was opened in June 2011, the total length of the bridge is 165 km. For comparison, the length of the Kerch Bridge is 18.1 km.

China built the Danyang–Kunshan Bridge in just four years. The construction involved 10,000 workers, costing $8.5 million to pay them. Most of the bridge runs along the Yangtze River at a distance of 8 to 80 km south of it. The length of the section that crosses Yangcheng Lake in Suzhou is 9 km. This part of the bridge supports 2,000 pillars. The height of the bridge above the ground is on average about 31 m (the height of the Kremlin walls reaches 20 m).

According to BBC Science Focus, the second longest bridge in the world is the Changhua–Kaohsiung Viaduct in Taiwan. The length of the bridge is 157.3 km. It was built in 2007 taking into account seismic activity, which is not uncommon in the region. The bridge was designed so that trains could stop safely in the event of an earthquake. Since 2012, it has been visited by more than 200 million people.

A viaduct is a special type of long bridge, usually consisting of a series of arches or columns. Despite the Latin origin of the word, the ancient Romans did not use this term; it is a later word that arose by analogy with the aqueduct. The bridge is part of the Taiwan High Speed ​​Rail and stretches from Zuoying in Kaohsiung to Baguashan in Changhua County.

Third place in the list of the longest bridges is occupied by the Tianjin Big Bridge (Langfang-Qingxian Viaduct). This viaduct connects Langfang and Qingxian and is part of the Beijing-Shanghai high-speed railway. It is one of the longest bridges in the world, with a total length of approximately 113.7 km. Construction began in 2006 and was completed in 2010. At the time of its opening in 2011, it was considered the second longest bridge in the world (according to the Guinness Book of Records).

The bridge consists of box girders 32 m long and weighing 860 tons each. They were created at two work stations along the bridge, and were delivered to the installation site on an already assembled section of the bridge.

Other famous bridges

The longest road bridge in the world is the 55 km Bang Na Expressway in Thailand. It was built in 2000. It is a six-lane highway and crosses only a small piece of water - the Bang Pakong River.

The longest continuous bridge over water in the world is the dam on Lake Pontchartrain in southern Louisiana, USA. In fact, this bridge is two parallel structures, and the length of the longest bridge of the two is about 39 km. It is supported by 9,500 concrete piles.

Bridge of the Future

Today, giant bridges in China, the USA, Europe and Russia withstand earthquakes of magnitude 8, winds of 250 m/s and collisions with ships. Most of the record-breaking bridges were built in Asia and the competition for the title of the most unique of them continues. Thus, a new bridge is being built in the Greater Bay Area. This eight-lane highway will connect megacities located on the banks of the Pearl River and will become part of the bridge between the million-plus cities of Shenzhen and Zhongshan. The project involves the construction of a 17 km long bridge, two artificial islands and an almost 7 km long tunnel with a width of 46 m. ​​According to the latter indicator, the facility will become No. 1 in the world among similar engineering structures.

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Larsen tongue and groove is a metal profile that is a groove with rounded edges of the side walls (grooves) or locks.

Arched

They began to be built in ancient times, and they remained popular until the industrial revolution and materials science allowed architects to create more advanced and efficient structures.

The underside of an arch bridge looks different than other types. All have a curved bottom that looks like someone cut a semicircle out of the bottom. Often such structures can be found within cities above small rivers, but also more massive ones above large rivers.

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Elements of bridge structures

Bridge structures (Fig. 2.5) are built to pass roads over rivers, gorges, ravines, hollows, and other roads. They interrupt the roadbed with their structures (Fig. 2.5, a), including spans and supports. The span spans the space between the supports, supports all loads moving around the structure and transfers them and its own weight to the supports. The supports absorb forces from the superstructure and transmit them through the foundations to the foundation soils.

Varieties of bridge structures are bridges themselves (see Fig. 2.1, a), overpasses (Fig. 2.5, b), viaducts (Fig. 2.5, c) and overpasses (Fig. 2.5, d).

Rice. 2.5. Bridge structures:

1 – span; 2 – intermediate support; 3 – abutment

Actually, a bridge is a structure for passing a road over a water obstacle.

An overpass is a bridge structure for passing one transport route over another at different levels. Overpasses are built in cities and outside cities, for cars and pedestrians.

A viaduct is a bridge structure for passing a road over a deep ravine, gorge or dry land with a high passage level above the bottom of the obstacle. A characteristic feature of viaducts are supports of great height (from several tens to hundreds of meters).

Overpasses are called bridge structures for passing the road at a certain height above the surface of the earth (see Fig. 2.6, d), so that the space under them can be used for various purposes. Overpasses are also erected instead of embankments to pass roads over river valleys, over swampy areas, and on approaches to overpasses. They are also used to pass expressways over urban areas, when widening embankments and organizing traffic in urban environments along rivers.

On mountain roads, in addition to viaducts and tunnels, galleries (Fig. 2.6, a), balconies (Fig. 2.6.6) and retaining walls (Fig. 2.6, c) are used.

Galleries are used to protect the road from avalanches and rockfalls, balconies are used to ensure the required width of the road on steep slopes and reduce the amount of work on soil development, retaining walls are used to keep the soil behind them from collapsing.

Rice. 2.6. Structures on mountain roads

Lunar

One of the most romantic types. The semicircular arch, reflected in the water, completes a 360-degree circle and resembles a full moon. These structures originated in Asian culture. They were originally built in China and then brought to Japan.

Mainly made of stone, wood and metal. Because they are steep, they have the advantage of not using up space from adjacent fields. This is a great way to encourage pedestrian traffic above the structure and boat traffic underneath it.

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Designers of the future road along the dam presented the first sketches

18:03, 01.09.2018 888
So far, nothing planned has been realized. The most realistic thing was, perhaps, the expansion of the exit from Green Wedge. The city even found a potential source of funding for this work.

The municipality submitted an application to include the Biysk road in the list of regional infrastructure projects. The region received more than 9 billion rubles from them. This money will be used to create transport and engineering infrastructure facilities in 2022-2023. However, the Biysk object was not included there.

The expansion of the road from Zelenka in prices of previous years was estimated at 400 million rubles. Taking into account the rise in prices for building materials, today the cost of the project is approaching 500 million rubles.

Mobile

Some of the most technologically sophisticated bridges are moved to accommodate boats and barges. It can be vertical lifting, lifting, rotating or transport.

They are driven by electric motors, whether hydraulic pistons, work winches or gears. In general they can be quite long. The main disadvantage is that road traffic must be stopped when it is open to water traffic.

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That we should build a bridge. British Army Pontoon Bridges and Ferries

This article will focus on floating and pontoon bridges.
But first, let's figure out what a floating bridge is, and what a pontoon bridge is, and what is its main difference from a floating one.

Floating bridge

is a bridge assembled to overcome a water barrier (river, lake, strait, etc.).

This bridge consists of two main parts.

The first is a floating bridge support: a boat or pontoon.

The second part is the decking or roadway, which is attached to the top of the boat (pontoon).

A type of floating bridge is a pontoon bridge.

. It is a structure in which a pontoon boat and a roadway are pre-connected into one whole. This connection constitutes a link in the bridge. When assembling a pontoon bridge, these links are connected to each other, assembling a passage over a water barrier.

Thus, a pontoon bridge is an improved version of a floating bridge.

An example of a floating bridge near Omsk. The floating supports made of barrels and the structure of the roadway made of planks are clearly visible

Ferry-bridge section of the PMP pontoon park. Here the floating support and the roadway form one whole, unlike the floating bridge design in the photo above

In our environment, the term “pontoon bridge” is more common. Therefore, in further presentation we will use this particular phrase more often.

So, in its simplest form, a pontoon bridge is a collection of shallow-draft boats attached to each other and set across a river or canal, with some kind of walkway or deck tied to the top.

Water acts as a support, so the lifting capacity limit is determined by the general and point buoyancy of the pontoons or boats.

The reality of pontoon bridges is that they have not advanced much in terms of their design since then.

Of course, there have been improvements in materials, methods of securing pontoons, decking materials, etc. All of this has resulted in increased lifting capacity, the ability to withstand fast river flows and high deployment speeds, but the basic principles have remained the same.

An even older version of the pontoon bridge is the river ferry. A simple, non-motorized, flat-bottomed boat that is towed across water using human, animal, or engine power.

A pontoon bridge will generally have a much higher capacity than a ferry, but the ferry has the distinct advantage of not blocking the river or channel to other vessels. On fast flowing rivers and rivers with high tidal levels, a pontoon bridge can also suffer without a serious shore anchorage system and constant attention from the bridge builders.

Pontoon bridges and ferries now often share common components. For example, the English Bailey Pontoon used many of the details of the Bailey Bridge, and the modern Air Portable Ferry Bridge can be used as a bridge, pontoon or ferry.

Therefore, it is sometimes difficult to separate the development of pontoon bridges and ferries because they are interrelated.

An example of a river ferry that is transported by a boat with a motor

Elements of the Air Portable Ferry bridge used as a ferry

The first pontoon bridges

Most historians believe that the first pontoon bridges were created and began to be used in China several hundred years BC.
They were commonly called boat bridges or pontoon bridges. Texts from the ancient book “Shi Jing” indicate that the first pontoon crossing in history was built in the 11th century BC. However, historian Joseph Needham, relying on more reliable sources, says that Chinese temporary pontoon bridges became common only during the 8th and 9th centuries BC.

The first more permanent and reliable pontoon bridges, connected by iron chains, appear during the Qin Dynasty between 221 and 207 AD. BC. Joseph Needham describes them as boats arranged in a row with planks laid across the boats, which is generally the same as the design of a pontoon bridge today. He also points out that Qing dynasty engineers improved pontoon bridges by developing more secure anchorages between boats and the roadway for permanent use.

An excellent example of such work by Chinese engineers is the Dongjin Bridge in Ganzhou, which was built during the Song Dynasty (960 to 1279 AD).

Modern version of the Dongjin Pontoon Bridge of the Chinese Song Dynasty

In Europe, an example of such bridges can be considered the pontoon bridges of the ancient Persians and Romans.

The most famous story is about a 2 km long pontoon bridge across the Bosphorus Strait, which was built in 493 BC. e. a Greek engineer for the Persian emperor Darius so that he could pursue the retreating Scythians.

Darius Pontoon Bridge

A little later, in 480 BC. BC, for Xerxes the Great of Persia, a large pontoon bridge was built across the Hellespont, or Dardanelles in modern terminology, which separated Asia from Europe. The first two bridges were made of papyrus and linen. It is therefore not surprising that they were destroyed during the storm. Xerxes reacted quite reasonably to this sad event at that time: he beheaded the engineers, ordered the water to be flogged and the construction of new bridges to begin.

First Xerxes Bridge

Later pontoon bridges (there were two of them) were stronger. As the Greek historian Herodotus wrote, they were built from more than 700 ships (approximately 360 ships per bridge), connected to each other by ropes. In addition, the ships, so as not to be scattered by a storm again, were installed on very heavy anchors.

In the first version of the bridge, anchors were only on the outermost coastal ships. After the ships were installed, boards covered with a layer of brushwood and earth were installed on top of them, forming a roadway. A fence made of branches was also installed on the sides of the roadway to prevent animals from panicking at the sight of the water surrounding them. The crossing of Xerxes' army took seven days and nights. At the same time, the army used the northeast bridge, and a huge number of servants and pack animals crossed through the southwest bridge.

Construction of the second bridge by the Persians

Xerxes' army crossing the second pontoon bridge

Alexander the Great sometimes carried ships with his army, divided into parts, which were assembled together when they reached the river bank, as when crossing the Hydaspes. The practice of using skins for inflation when troops had to cross a river was adopted by the Greeks, Romans and Mongols.

Assyrian soldiers used bags filled with air to cross rivers

Crossing Hannibal's troops on rafts across the river

The Romans were also great military engineers, and many of their military installations still stand today.

During the First Dacian War in 102 AD, Roman engineers built a large pontoon bridge over the Danube. The structure of the bridge, like its predecessors, consisted of connected boats and a plank deck.

Roman pontoon bridge over the Danube

A few years later, this event was overshadowed by the construction of another famous stone bridge, Trajan's, which was 1,135 m long. For more than a thousand years, this bridge was the longest arch bridge in the world.

Reconstruction of Trajan's Bridge over the lower Danube, carried out by engineer E. Duperrex in 1907

Pontoon bridges began to be used more widely in the 17th century.

During this time, pontoons were used as regular components of army trains: the Germans used leather, the Dutch used tin, and the French used copper "hide" on strong wooden frames.

In the mid-18th century, the Russians invented a collapsible pontoon, consisting of canvas fabric stretched over a wooden frame. For transportation, the frame was made collapsible, and the tarpaulin was folded. This was the pontoon park of Andrei Nemoy.

General view of the bridge from A. Nemoy Park

Drawing of a canvas pontoon from the book by A. Nemoy “Guide to the knowledge of marching bridges”, 1781

Great Britain

Now let's move on to English bridges.
One of the first examples of military bridging in Britain was King Edward I's attempt to cross the Menai Strait in Wales. Although this attempt was technically successful, tactically it turned out to be a failed operation.

In 1277, to suppress a Welsh rebellion, King Edward I sent a force of 2,000 soldiers to capture Fr. Anglesey, thereby depriving the opposing forces of most of their food supplies and outflanking the defending forces at Conwy.

To overcome the strait, the caretaker of the Cinque ports (Stephen de Pencaster) was tasked with building a pontoon bridge. For this work he used carpenters and shipwrights from his area. In terms of design, the new bridge was no different from all previous ones. It also consisted of several interconnected boats and a roadway made of log decking. This structure was called the “boat bridge”.

Unfortunately, the bridge elements were too heavy to transport. Therefore, it was decided to build a bridge in Chester, closer to the territory of the rebels.

Stephen de Pencaster Boat Bridge

Despite the fact that the bridge was in perfect order, poor communication and coordination played a negative role. As a result, British troops crossed the strait at the most inopportune moment and found themselves caught between the rising tide and the opposing forces. All this led to a disastrous result.

This is how Walter of Guisborough described it in his chronicle:

“When they reached the foot of the mountain and after some time came to a place some distance from the bridge, the tide came in with a great flood, so that they could not return to the bridge because of the great water. The Welsh came from the high mountains and attacked them, and in fear and trembling because of the great number of the enemy our people preferred to face the sea rather than the enemy. They entered the sea, but, heavily loaded with weapons, drowned instantly.”

Edward also used military bridge builders in Scotland, this time more effectively. The King commissioned military engineer Master Richard to create a set of portable bridges at King's Lynn in Norfolk. It was decided to use the bottom bridges in the future to cross the Forth River, carefully bypassing the well-protected stone Stirling Bridge.

The next stage in the use of pontoon bridges dates back to the beginning of the 19th century.

There are fragmentary accounts of the use of a number of improvised pontoon bridges in India by General Sir Arthur Wellesley early in the century, but without specific examples.

English pontoon bridge across the river. Indus

In 1809, during the Napoleonic Wars in Spain, Lord Wellington ordered the destruction of a stone bridge over the Alcantara River to prevent French freedom of movement. Although the explosion initially did not completely destroy the bridge, after some time one arch collapsed on local residents. This left a negative impression on the military, especially since it was an operation led by British forces.

When the tide of the war changed, in April 1812 Wellington ordered Lieutenant Colonel Sturgeon to repair the previously destroyed bridge or build a pontoon bridge. Sturgeon was not an officer in the Corps of Engineers, but an officer on the Royal Staff. According to his plan, a suspension bridge over the destroyed arch was the best option. Construction took place away from the bridge site, and its elements were transported by wagons. After the ropes were stretched across the span in place, the rolled bridge was unrolled and secured to them.

This is how the episode is described on the Napoleon Series website by General Leith Hay, commander of the 5th Division:

“The destroyed arch had such a long span and the bridge parapet was so high from the river bed that repairs using timber were impossible. The passage to be crossed was ninety feet (27 m) wide, and the height of the bridge one hundred and eighty feet (54 m) from the bed of the river... The work was begun by installing two beams on supports four feet (1.2 m) high and ninety feet apart. They were attached to the side and end walls of the building with staples and slings to prevent them from moving closer together due to the tension of the ropes. Then 18 cables were stretched around them, running from one end to the other. Eight pieces of wood, six inches square, were placed on the ropes at equal distances, with notches one foot apart cut into their surfaces to secure them; These recesses were burned with a hot iron so that the ropes did not rub. The cables were then tied to the beams; these were tied together with rope yarn, and the sleeper chains were screwed and laid on the net, and attached to two beams originally placed at the ends of the work. The boards were cut and prepared for laying crosswise, drilled at the ends to create a line designed to secure them to the sleepers and to each other... The next stage was to prepare the edge of the broken part of the bridge and cut channels in the masonry to receive purchases. When they arrived on the spot, four strong cables were stretched from side to side as conductors for the passage of the cable-stayed bridge, the beam on the south side having been previously sunk into the masonry; then the whole thing was pulled out by a winch installed on the opposite pier.”

To understand the importance of this moment and the subsequent destruction of the French pontoon bridge across the river. Tagus at Almaraz, it must be said that these two actions reduced the march distance for Wellington's troops by 250 km and added 650 km for the French.

Model of Lieutenant Colonel Sturgeon's Alcantara Bridge

Also in 1812, significant efforts were made to build bridges across the Tagus River. But all efforts ended with the construction of a stone bridge more than 190 m long.

When Wellington won in Spain, he moved to France.

To block the French army on its way to Toulouse, it was necessary to cross the Adour River. The choice of crossing point was complicated by the presence of French garrison forces, so to provide some protection for the crossing, a place downstream was chosen, but this meant that the river was wider here (almost 275 m), and the bank was subject to strong tidal fluctuations.

The solution to this important task was entrusted to two officers of the engineering troops - Lieutenant Colonel Elphinstone and Lieutenant Colonel Burgoyne, as well as the well-known Lieutenant Colonel Sturgeon, who represented the Royal Service Corps. Lieutenant Colonel Burgoyne was later promoted to Field Marshal and, incidentally, one of the buildings (the Burgoyne Study Center) at the Royal School of Engineering in Chatham is named after him.

Due to the large width of the barrier and the strong tidal fluctuations, it was obvious that a conventional pontoon or suspension bridge would not be suitable for the job. Therefore, military engineers decided to use local coastal vessels called chasse matrees.

These were large boats, some of which exceeded 15 meters in length. 48 boats were “rented”. The plan developed by the lieutenant colonels provided for the mooring of boats with a bridge surface consisting of wooden planks at a distance of 10 to 12 meters. Because of the large quantities of timber that would be required, Lieutenant Colonel Sturgeon proposed a technique similar to that which he had used in the construction of his bridge over the Tagus in Spain, that is, the use of ropes to provide a surface on which fewer planks could be placed.

The cables were extended to the shore from the two central boats and secured with weights (18-pounder guns) and capstans anchored in the ground. To keep the boats on the water, each of them had its own anchor, and some had two anchors.

Due to the fast flow of the river, this was more difficult to do than suggested. It took a lot of effort to install the bridge, but it was worth it. Only 34 boats were delivered to the bridge construction site. The rest were lost due to bad weather and tide. A few days before the construction of the crossing began, a bridgehead was captured on the opposite bank. Its defenders had to repel several French attacks.

The bridge was quickly completed overnight, and by noon the next day troops, wagons and artillery were transferred across it.

Historian Napier said of the bridge:

“A monumental undertaking that should always rank among the wonders of war.”

Construction of a floating bridge across the river. Adur

The Duke of Wellington took a keen interest in military bridging and was fully aware of the strategic advantages it could provide. Therefore, much more attention began to be paid to this subject.

Permanent bridge trains were introduced and the structure of the Royal Engineers in the Corps of Royal War Masters was created. In 1812 a permanent training center was established at Chatham to train the Corps of War Masters (later the Corps of Sappers and Miners) and Royal Engineers.

During the Peninsular War, Wellington also realized that bridge equipment needed to be highly mobile, so he ordered some of the horses from the artillery train to be removed and given to the engineers.

In his dispatches he wrote:

“We are unfortunately delayed due to the movement of our bridge, without which it is obvious that we cannot do anything, the equipment is quite new and only comes from Abrantes, but there have already been many breakdowns and I understand that the carriages are terribly bad. I will have the sad work of this bridge throughout the campaign, and yet we can do nothing without it.”

Transportation of pontoons by bridge train. 20th century postcard

The end of the Napoleonic Wars ushered in almost 50 years of peace in Europe. But British forces continued to be used abroad, for example in India.

In 1839, during the offensive against Afghanistan, a pontoon bridge with a very large span was built at Bukkur (now Pakistan).

Bukkur is a fortified island and a natural passage on the banks of the Indus between Sukkur and Itore. The bridge itself consisted of two spans, one 200 m long and the other more than 300 m long. The construction of this bridge took more than 90 boats and 14 days. Although the high speed of the river and its rocky banks created problems, the bridge allowed several thousand soldiers and dozens of pieces of equipment to be transferred across it.

Bridges continued to play an important role throughout the 19th century during hostilities in Abyssinia, Crimea, India, West and South Africa.

The early open pontoons had a number of disadvantages, the biggest being the difficulty of transporting them to site (if not by river) and their susceptibility to bad weather. Therefore, in the early 1800s, a concerted effort was made to improve bridge design.

In 1814, Colonel Sir James Colleton (otherwise known as Colleton) designed a cylindrical pontoon buoy with conical ends and made of wooden staves like a barrel. This invention, unfortunately, was not successful. But the closed pontoon became the basis for later types.

The first significant development after this was the Pasley pontoon of 1817, designed by Lieutenant Colonel Charles Pasley of the Engineering Establishment at Chatham. Pasley's pontoon differed from open boats in a number of key ways. It was enclosed and therefore had greater resistance to flooding, had many fastening points for attaching the road deck and, perhaps more importantly, was sectional - consisting of two parts.

The bow of each part of the pontoon was pointed, and the stern was square-shaped. This made it possible to split the pontoon, as indicated above, into two parts (half-pontoons) for easier transportation. When the bridge was assembled, a pair of these pontoons were connected stern-on to form a single float (single support), both ends of which were pointed, an important consideration for use on water obstacles.

The pontoons were built from lightweight wooden frames covered with copper sheets and clad in wood. Each half-pontoon was divided into waterproof compartments and equipped with means of pumping out water. To transport the bridge, a pair of half-pontoons and the superstructure of one bridge span were loaded onto one trolley.

Sir Charles Pasley

And his pontoon

The Pasley pontoon served for many years, but was replaced in 1836 by the Blanchard pontoon, which was cylindrical with parabolic ends, consisting of tin cylinders 3 feet (0.9 m) wide and 22 feet (6.6 m) long, spaced 11 feet (3.3 m) apart, making the pontoon very buoyant. Two pontoons and two superstructure compartments were transported on one trolley.

With one or two modifications, Blanchard pontoons were used by the British Army until the late 1870s, but were eventually abandoned.

Blanchard pontoon model

In the late 70s of the 19th century, British engineers returned to the open pontoon design, which was followed by engineers of all continental armies at that time.

Blanchard's pontoon was followed by a pontoon designed by Colonel Binden Blood.

The pontoon was named Blood, in honor of its creator. Its design, as noted above, returned to the concept of an open boat with decked ends and partially decked sides on which oarlocks were attached. The sides and bottom were of thin yellow pine with canvas attached to both surfaces with Indian gum mortar and coated on the outside with marine glue.

General Sir Binden Blood

In his memoir, Four Score Years and Ten, published in 1935, Binden writes:

“In 1865, I was appointed to one of the detachments of the Royal Engineers, whose specialty was transportation and the rapid construction of floating bridges on the First Line. In November 1866 I moved to Chatham with this detachment. We spent an instructive and very pleasant year there, returning to Aldershot in November 1867. While my party was at Chatham in the summer of 1867, our superior authorities decided that our equipment for a pontoon bridge was unsatisfactory in some details, and invited the officers to submit designs for a new sample. So I submitted a new design, which was approved for trial, and some time after my detachment returned to Aldershot in November 1867, I was sent back to Chatham to carry out the necessary production and experiments by order of the RE Committee, which then dealt with such questions. I remained at Chatham, with a short visit to Aldershot in 1870, until I went to India in 1871, and the new pontoon equipment was finally accepted for supply in 1870.”

Binden Blood's pontoon in transport position

Already in India in June 1879, Binden Blood personally supervised the construction of his own bridge at Fort Pierce, which was supposed to replace the ferry that had been operating there for about 9 years, operating on a cable stretching from coast to coast.

The length of the Blood pontoon bridge was about 250 m.

It must be said here that the future British Prime Minister Winston Churchill served under the command of Binden Blood in the Malakand Field Forces.

It is also important to note the fact that Queen Victoria herself showed interest in the Blood pontoon bridge. She was directly present at the construction of the 240-foot (72 m) bridge over the Thames at Datchet near Windsor. She apparently found the event interesting, for the next day the Queen appeared at the bridge again to witness its removal from the water barrier.

We find a description of the Blood pontoon (or in the literal translation of the “Bloody Pontoon”) in the “Treatise on Military Carriages and Other Products of the Royal Crew”:

“The pontoon can be used as a bridge pontoon or as a boat: its exterior dimensions are 21' 1" x 5' 1" x 2' 6.5" deep; its weight is 7 cwt per pound, and its tonnage is 9.685 tons. In horizontal section it is rectangular, its sides are almost straight and vertical, and the ends are rounded. The frame, which is very light, is made of yellow wicker and elm, the straight parts being made of the former, and the curved parts of the latter. The frame is clad in yellow pine and each side of the clapboard is covered with a canvas attached with Indian rubber mortar. Before painting, the pontoon canvas is coated with marine glue, and the bottom is protected by four longitudinal stiffeners covered with iron friction plates. The pontoon has eight wooden handles on the sides, about halfway up, six attached with ropes and two with wires. Moreover, the latter serve as eyes for fastening the cables, it also has a ring at each end for the cable and is equipped with four oarlocks along the gunwale on each side and at each end one for the steering oar; there are also provisions for attaching the saddle beam.”

In this situation, a natural question arises.

Why, having advanced closed pontoons, did they still return to the open boat design?

At the time, the answer turned out to be very simple.

Experience with tubular or round structures such as Blanchard pontoons has shown that when submerged more than halfway, they become unstable and difficult to handle. So one idea to counteract this was to make the pontoons triangular in shape. That is, tapered towards the bottom, like those of ships.

This shape was necessary so that when pressure from passing loads is applied, a larger volume is immersed, and this forms a more stable and increasing counterforce. The idea was good, but impractical with the construction techniques of the time. Therefore, it was decided to return to the design of a conventional open boat. In fact, numerous European armies, especially the Dutch and French, given their considerable experience with pontoons, never used the British method of enclosed pontoons. Clearly this was a case of experience winning over new designs.

The “Bloody Pontoon” indeed had a number of important features. For example, a longitudinal support beam was installed on the pontoon to take the load from the deck. This beam could easily be removed if the pontoon were used as a regular boat.

Around this time, the Royal Engineers, like many European armies, formed a special pontoon force.

These troops were manned by tall and physically strong soldiers because they had to physically lift the heavy pontoon equipment. These specially created units performed well in the South African wars and, thanks to their physically strong fighters, won no less than thirteen championships in tug-of-war between units of the British army!

A further development of the Blood pontoon was the Mark II pontoon or Clauson pontoon, which was destined to remain in service until 1924.

Clauson pontoon drawing

The pontoon is named after Royal Engineers Lieutenant J. E. Clauson.

This weapon element was, in fact, a modified “Bloody Pontoon”, divided in half. It also demonstrated a return to the multi-section design previously proposed in the Pasley pontoon and the highly successful Austrian Birago pontoon.

Drawing of Clauson's pontoon

Royal Engineers pontoon unit on the march with a Clauson or Mark II pontoon - 1915

Instead of two identical sections, Clauson's pontoon used a pointed bow and square stern configuration. These two sections could be used independently of each other if necessary. The parts of the pontoon were connected together using phosphor bronze fittings. This flexibility in use allowed the assembly of a diverse range of bridge configurations, from light infantry bridges to heavier van and vehicle types.

The photographs below show the Mk II pontoon bridge in action during the First World War.

A British artillery battery crosses a pontoon bridge over the Diyala River near Baghdad in March 1917. This bridge was built by the 71st Field Company, Royal Engineers, at 11am on 10 March after a night crossing of the river by the 5th Battalion, Wiltshire Regiment. The 88th Field Company, the Royal Engineers and the 8th Welsh Pioneers provided a bridgehead on the Turkish-held side of the river (photo from remuseum.org.uk)

D Company, 1st Battalion "Cameronians" (Scottish Fusiliers) crossing the pontoon bridge over the Marne at La Ferté-sous-Jouare, 10 September 1914 (photo from remuseum.org.uk)

Very often, when arranging a pontoon crossing, we encountered the problem of connecting the bridge to the shore. This is especially important if the bank is higher than the road deck or the river is tidal. Some arrangements are required here to provide access from the river bank to the pontoon bridge deck.

The British solved this problem simply.

They used the experience of the Austrian army, where they used the Birago overpass to cross from the shore to the bridge and back.

Trestle (goat) Birago - an invention of the Austrian military engineer Karl von Birago, one of the types of fixed supports for pontoon bridges

The video below shows an Austrian army training exercise in 1939. In them, military engineers are setting up a coastal crossing using an overpass that looks like a Birago goat! At the turn of the century, the Birago flyover was replaced by the Weldon flyover.

At the outbreak of the First World War, two Royal Engineers bridge trains were fitted with Mark II pontoons and Weldon trestles, as an addition to the range of light raft equipment derived from much earlier designs.

Drawing of the Weldon overpass

Weldon trestle and Mk II pontoons used on the Tigris River, 1917

Developments during the First World War included the introduction of the Marston Lever Trestle and the Mark IV trestle into pontoon bridges.

The video below shows Australian Anzacs building bridges across the Nile River in Egypt during the First World War. The footage clearly shows the Mark II pontoons and the Weldon Trestle, the bridge installation process, and the use of the pontoons as a ferry.

As the weight of vehicles and artillery increased, it became apparent that the floating bridges would need to be modernized to accommodate the changing conditions.

These developments included the Mark III pontoon, the Mark II with different cladding and the Mark V trestle, which remained in service until the 1920s.

A number of floating bridges were designed and used during the war, but in relatively small numbers, including the Type B Sankey Bridge, which used steel beams instead of timber beams on a Mark II Pontoon and a heavy steel pontoon.

The next major achievement of English military engineers was the Inglis Heavy Floating Bridge, unique at the time because it used a continuous girder design to distribute the load across a series of new heavy pontoons. Despite significant progress and successful trials in Christchurch, Dorset, the bridge was not adopted because the war had already ended.

Inglis Pontoon Bridge. Tank bridge trials at Christchurch, Dorset, late 1918

The Inglis heavy floating bridge being tested, 1918. Still from a film about the tests from the website www.iwm.org.uk

In the late twenties of the twentieth century, a number of new pontoons and trestles were introduced, including the Mark IV pontoons and the Mark V trestle, as the ferry equipment was updated.

The Mark IV pontoon was completely enclosed and consisted of Consuta plywood, so it was often called a Consuta pontoon. With safe buoyancy, the bridge's load capacity was 6.5 tons.

The figure below shows the method of making the pontoon hull skin.

The brass was a continuous stitch that looped in and out of the body through the wood lining. The Consuta has four veneers (overlays that replace the outer layer) of mahogany, laminated with calico (canvas impregnated with linseed oil) to ensure the skin is waterproof.

This design resulted in a very light but very durable body. Copper was used because there were no waterproof adhesives at that time. This form of stitched construction was patented by Saunders and the plywood was named Consuta plywood.

Pontoon Consuta. Drawing from the pontoon manual

The Mark V sawhorses were the first to use mild steel instead of wood.

The next Mark VI sawhorses were much more powerful and were introduced in 1929. Goats could be used without pontoons as extreme bases for crossing narrow obstacles.

A Morris Carrimore light truck of the 17th Field Company, Royal Engineers, towing a pontoon on a trailer.

The video below from Pathe shows the moment the Mark IV pontoon bridge was erected.
To be continued…

Underlined ribbon

A tensioned ribbon bridge, also called a chain bridge, is a tension structure. It has two or more suspension cables built into the deck. These cables follow the arc of the catenary between the supports and provide rigidity.

The structure is usually made of concrete reinforced with steel tension cables. These bridges are very aesthetic, economical, and require virtually no maintenance. According to the editors of TopCafe, these are some of the most beautiful bridges in the world.

7

Five longest bridges in Russia

Until the bridge across the Kerch Strait is built, the five large-scale crossings look like this:

• Russian bridge in Vladivostok. The length of the structure is 3100 m, the opening took place in 2012. The need for it was first thought about in 1939, but was implemented at the present stage.
• Bridge in Khabarovsk. Its length is 3891 m. It has two tiers. The lower one is open to rail traffic, and the upper one is open to road traffic. His image adorns the five thousand dollar bill.
• Bridge on the Yuribey River. It is located beyond the Arctic Circle in the Yamalo-Nenets Autonomous Okrug. The length of the structure is 2893 m.
• The bridge across the Amur Bay has a length of 5331 m. It was opened in 2012. It is interesting for its lighting system, which helps save up to 50% of electricity.
• Presidential Bridge over the Volga in Ulyanovsk. Its length is 5825 m. Construction took place over 23 years.

From box beams

Photograph: Scott Davis, CC BY-SA 3.0, via Wikimedia Commons

The main beams consist of hollow box beams. The box beam is made from structural steel, prestressed concrete, or reinforced concrete and steel.

The box is usually trapezoidal or rectangular in cross section. This reduces the thickness of the slab, and therefore the weight of the entire structure. These bridges are mainly used for highway interchanges and modern elevated light rail structures.

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Purpose of artificial structures on roads

The main purpose of artificial structures on roads is to ensure the safe movement of vehicles and people. Moreover, each design has individual characteristics regarding its intended use:

• Pipes. Stacked for crossing streams/dry valleys. Often installed under ramps/crossings. The purpose is to conduct water under the road surface. Can be used for driving livestock in villages.
• Tunnel. A structure designed to carry a highway through a mountain/water area. In the mountains they are projected across slopes/ridges. Partially perform the function of protection from negative natural disasters, for example, landslides or screes.
• Bridge. The construction of bridges on highways is necessary to overcome water areas, gorges or other obstacles through which the road cannot be continued. This design takes on the weight of traffic flow in a certain area, and therefore requires special attention to installation.
• Viaduct. One of the types of bridge, which has a large height and is located above a gorge or other depression. Typically, such structures have one span due to the high cost of construction.
• Overpass. Used to organize traffic flow on another road. Structurally, such an artificial structure is one of the types of bridge.
• Retaining walls. Necessary for maintaining road surfaces on mountain slopes. They are installed instead in regions with a risk of talus/landslides. They are made of concrete, stone or reinforced concrete.
• Overpass. It is erected at the intersection of highways and is an embankment structure with a road surface on the surface.

The category of artificial structures also includes galleries that are built on mountain roads. Their main purpose is protection against falling stones, avalanches, landslides, etc. In such structures, special attention is paid to strength.

Segmental

Unlike traditional construction methods, which build structures in large sections, segmental construction is built from small pieces called segments.

They consist of concrete parts that are either built elsewhere and transported to the construction site, or constructed entirely on site. Although this type of construction is very economical for long spans, it requires high-tech machinery and special safety precautions during construction.

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Metal bridges

Most modern bridges involve the use of metal in the load-bearing parts of the structures. For quite a long time, a metal bridge was considered the most durable type of structure. Today, this material is an important, but not the only component of bridge connections.

Types of metal bridges:

• Arched structures.
• Viaducts with spans.
• Hanging, cable-stayed.
• Overpasses with supports made of reinforced concrete, where the spans are assembled from metal connections.

Metal structures have the advantage of being easy to assemble, which is why almost all types of railway bridges are built from this material. The metal parts are industrially manufactured in a factory and the size can be adjusted. Depending on the load-carrying capacity of the mechanisms with which the installation will be carried out, factory blanks for the future one-piece connection are formed.

The structure can be welded from parts directly at the final installation site. And if previously it was necessary to connect many parts of one span, now a crane with a lifting capacity of 3600 tons can easily carry and hoist an all-metal span onto supports.

Viaduct

The viaduct consists of a series of small spans between tall towers. Its purpose is to carry a road or railway through a valley or wetland. Although they are much more cost-effective than long-span bridges or tunnels, they usually lack vertical and horizontal clearance for large vessels.

Those built over water use successive arches or islands. They are usually connected to tunnels or other types of bridges to cross navigable waters in the form of viaduct sections.

10

Meaning of the word bridge

male bridge platform, laying, plank, ramp, all kinds of continuous flooring made of boards, logs, beams, for riding and walking; a continuous building across a river or ravine for crossing; Such a bridge can be: wooden, stone, iron; on vaults, stilts, trestles; living or floating, from log rafts; floating, ship or pontoon, on ships or boats; flying, hanging, thrown without a middle support, on some coastal abutments; Often it is also a chain, removable bridge, installed only temporarily, for example for the summer; adjustable, built for the passage of ships; lifting, for example, done through fortress ditches, etc. The bridge is not a great post, you can go around it. This is a dime a dozen, even bridges can be bridged! a lot of. Well done at least bridge the bridge. Front to rear axle, in any case. The front rear axle is in the graveyard. More expensive than the stone bridge (on the Moscow River). It's not the devil that brought you to the bridge. A kind person is better (or more reliable) than a stone bridge. Remember the bridge and transportation (back when there was a toll on bridges). Sit under the bridge; stand around the corner (i.e. rob). He is a tailor, and his workshop is on the main road, under the bridge. Chigiriki, migiriki, sharanda, baranda, across the bridge, across the bridge, across the Lykov bridge, shushel, went out, the stench went! they end up. The bridge is paved under a pillow, from twigs, splinters, and from dreams they conclude about fate. Who builds such a bridge without a knife, without an axe, without wedges, without sub-blades? freezing. Do they grow on the iron bridge? frying pan with pancakes. Under the bridge, under the tier (?), the cloth is green in a single row? winter There is a bridge for seven miles; on the bridge there is an oak tree, on the oak tree there is a club, on the club the color is all white? Lent and Easter. | A bridge or bridges, a log structure, a pavement over a swamp; | hut floor, platform, especially the porch and large entryway (northern, eastern, eagle, tamb., Ryaz. smol.). Do you have the Savior, Mother of God, on the bridges on Kalinov? Vologda Is there an image in the hallway at the door, are you baptized? Viburnum bridges are remembered in songs and fairy tales. Under the bridge (senior) there is a sheepfold or basement; the bridge separates the front hut from the rear, winter hut, and from the rear bridge, i.e., the rear part of the vestibule, a door leads to the barnyard. Look for the ax on the bridges, sib. in the entryway. A sad bridge, at the mining factories, a sloping road between the pigs, from the pond; drain bridge to drain excess water. | In cards, a bridge is called one of the cheating tricks. To pave the bridge, a kind of girlish fortune-telling, with splinters. The bridge will belittle. on ships, a type of bridge across the deck, above the wheels; watchman's place. Bridge, bridge, bridge will diminish. bridge, -on, bridge taken away. Bridges pl. wooden pavement, steel, along muddy roads, on unreliable ice. | Construction scaffolding, scaffolding. | Masonry, lava, crossbars across a stream, ravine, Nov. bridge. | Kaz. bridge, entryway, porch in front of the entryway. Mostets husband ,

Dahl's Dictionary

Cantilevered

Constructed using cantilevers, structural members that run horizontally and are supported at only one end. For small pedestrian bridges, the cantilever can be simple beams.

Cantilevers are useful for blocking a waterway without dividing it with river piers. They are mainly used for pedestrians, cars and trains. The longest cantilever bridge in the world is the Canadian Pont de Quebec, built in 1917.

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Suspension

In suspension bridges, the cables supporting the deck are suspended vertically (called hangers) from the main cable. This main cable is secured at both ends because any load applied to the structure is converted into a tension force.

A suspension bridge requires less materials to construct and longer spans can be achieved compared to other bridge types. This type is best able to withstand earthquakes.

12

Cable-stayed

Cable-stayed bridges have become widespread since the 19th century. They consist of one or more columns (or towers) with cables directly supporting the deck. Columns absorb and cope with compression forces.

Unlike overhead, this type has cables that run straight from the tower to the deck, forming a series of parallel lines or a fan-shaped pattern. In this range, the cable-stayed bridge remains economical and elegant due to the relatively shallow beam depth.

13

Beam

During construction, they use steel or concrete beams. The beam is the main horizontal support that supports the smaller beams on the deck. Girder bridges have come a long way from their limited short-span applications to a cost-effective functional form, becoming one of the most widely used bridge types. Now these types use modern, more durable materials.

14

Overpass

The crosspiece consists of several short spans supported by closely spaced frames. The trestle, which is used as a bridge support, is a rigid frame made of wood or iron.

Iron and wooden trestles were widely used throughout the world in the 19th century. Although these bridges are largely obsolete, they are still invaluable to infrastructure transportation systems. For example, steel or wood trestles are often constructed in areas where a buried bridge could block potential flood waters.

15

Bridge classification

When studying car axles, it is important to take into account their classification according to basic criteria: purpose, location, design and type of suspension. Let's look at each type in more detail.

By purpose

The mechanisms under consideration differ in purpose and are of the following types:

1. Presenters. The task includes connecting the wheels of the driving axle, as well as transmitting torque from the power unit, braking and other forces. The design includes axle shafts, wheel hubs, the main gear and its housing, brake drum, etc. If the drive axle operates on a hydraulic or electric principle, the design may differ. Depending on the vehicle, the drive axle is located on the front/rear axle or both.
2. Steerable. Structurally, they include elements of the steering system, which improves the vehicle’s handling. At the same time, the function remains unchanged - connecting the wheels. Can be located on the front/rear axle. The quantity can be from one or more. Most often, the steering axle is located at the front, which is important for special equipment, but the rear location is more popular among utility vehicles.
3. Combined. It is clear from the name that such devices combine the tasks and features of the types discussed above. Combined axles are most in demand in passenger cars with front-wheel drive. They have a differential and final drive, and the drive force is transmitted using a CV joint. Internal units provide vertical movement, and external units provide wheel rotation.
4. Supportive. They are a beam with wheel hubs located on both sides. The task of the mechanism is to transmit vertical loads and commands from the braking system. This configuration is typically used on the rear axle of front-wheel drive vehicles. It is distinguished by its design simplicity and reliability. In addition, such devices are used in trailers/semi-trailers to increase cargo transportation performance due to a more even distribution of weight over the surface.
5. Walkthroughs. A type of drive axle, the function of which is to transmit torque from the engine to the rear axle (also driving). To solve this problem, a special shaft is used. This mechanism is used only on vehicles with two or more drive axles.

By location

When classifying vehicle axles, their location must also be taken into account. There are several options available here:

1. Front. Located on the front axle. The functions include connecting the wheels and partially supporting the vehicle. Such bridges can be driven or steered. In vehicles with all-wheel drive, an adjacent arrangement is most often found. The exception is agricultural machinery and transport of public utilities, where the bridge is both not controlled and not driven. Structurally, the front axle can consist of a beam with hubs installed on it or a load-bearing cross member with swinging arms. Popular manufacturers of such units include ZF, Delphi Corporation and others.
2. Rear. The functions of this mechanism include connecting the wheels of the rear axle and creating support for the corresponding part of the vehicle. Such bridges can be driven (the usual version) or steered. The second option is more relevant for special equipment (agricultural, utility and other types of machines). In cars with front-wheel drive, this unit is not controlled or driven. Fastening is carried out to the frame part or body of the vehicle. The main manufacturers of rear axles are Delphi Corporation, WulfGaertner Autoparts AG and others. Structurally, it consists of a cardan, a driven gear and satellites that rotate the axle gears.
3. Intermediate. This group includes bridges that do not fall into the categories discussed above. If the car has only two axles, such a unit is not provided. As in the cases discussed above, the intermediate bridge can be driven, driven, or used as a supporting mechanism. Structurally, such an axle has much in common with the rear one. The difference concerns only the location of the main gear in relation to the longitudinal axis.
4. Rolling. A design that can be detached from the trailer/semi-trailer. It is used to increase capabilities in terms of cargo transportation. Takes on a supporting function.

By design

When considering bridges, it is necessary to take into account their design features. There are two options here:

• With detachable/one-piece beam. Such a system has an empty interior for installation inside drive mechanisms. Devices with a one-piece beam are distinguished by greater reliability, which makes it relevant to use the mechanism on cargo and special vehicles with a large dead weight. The split beam is used, as a rule, in passenger vehicles and trucks with a load capacity of up to 3.5-5 tons.
• With crossbar. Such bridges have the appearance of an I-beam with varying diameters. They are made using timber from metal obtained by forging. Such an element is mistakenly considered a beam. This is not entirely true, because the main difference is the bend in the central part for more convenient placement of the power unit.

Beam bridges also differ in technology. They are:

• stamped (cast iron) - made by welding, have a rigidity indicator between cast and split beams;
• detachable - distinguished by the presence of a connector in the crankcase area, which is connected using a bolted connection;
• cast (steel, cast iron) - characterized by maximum rigidity and reliability, used in special vehicles, but have an expensive and complex technology;
• one-piece - they are a solid beam with axle shaft sleeves inside, they are characterized by high rigidity and ease of maintenance, and do not require removal of the bridge for repairs.

By suspension type

Structurally, all vehicle axles are divided according to the type of suspension. They are:

• Uncut. It is a solid axle in which the wheels are mounted at the ends of the beam. Whenever one wheel moves, the second one moves. Such bridges are often called “living” bridges. They are mounted on the rear of many vehicles, including four-wheel drive trucks. Sometimes used on the front of heavy trucks that need to transport large loads. The advantage of this design is that body roll does not affect wheel camber, and the wheel alignment angles are easy to maintain. Among the shortcomings are increased vibrations and shaking during movement.
• A split bridge is a mechanism that, according to its operating principle, is the antonym of a continuous bridge. Here the wheels are connected to the beam through an intermediate link, the role of which is played by the suspension. The rotation of one wheel, for example, when driving through uneven areas, does not affect the position of the other axle.

Cable-stayed with cantilever spar

A modern type of cable-stayed bridge. In such a design, the distribution of forces does not depend solely on the cantilever action of the spar (support tower). The weight distribution in the spar and the angle between the spar and the bridge play an important role in reducing the overturning forces applied to the base spar.

Sometimes the spar is raised to an angle where it is balanced by the structural tail. Many designs have a backward-curved spar that supports the weight of the deck.

Wooden bridges

The first bridges in human history were built from wood. For a long time, these structures could not be used without appropriate repairs, constant preventive maintenance and replacement of individual parts and fastenings. This was associated with construction difficulties and the fragility of the material itself. The following types of wooden bridges are currently being built:

1. Depending on the system - beam, strut.
2. Depending on the design - package buildings with spans, truss bridges.

The beam structure is the simplest, and therefore the most quickly assembled structure. The support beams are driven into the ground to a depth of 4 m. Nozzles are placed on the upper ends of the piles using steel pins, all piles are tied into a single whole, and a canvas for movement is laid on top. When building a wooden bridge, it is important to create a strong connection between the structure and the embankment of soil at both ends, this is done so that the bridge is stable.

Now there is a tendency to revive the construction of wooden bridges, which is associated with the advent of technology for manufacturing laminated veneer lumber, which is more resistant to aggressive environments, external torsional forces and is more durable in operation, moreover, its length does not depend on the natural growth of the tree.

Cable-stayed with side spar

A rather unusual bridge in which the cable support does not block the roadway. Instead, it cantilevers on one side. Cable runs are usually aligned along the centerline of the entire structure. Forces are transmitted through cable supports, then through compression supports and then into the foundation.

Such unusual engineering structures are suitable for regions where the road goes upstream, crosses a stream and turns back on the other side in a downstream direction. By building part of the turn on a structure, the turn can be smooth, allowing vehicles to move faster.

17

BRIDGE

Rice. 1. Types of bridges according to the static scheme: a – split beam; b – continuous beam; c – beam cantilever; d and e – frame; f and g – arched; h – hanging; And…

BRIDGE, a bridge structure designed to carry transport routes across water barriers. M. are distinguished by purpose: road (for the passage of all types of vehicles moving on roads, as well as pedestrians), railway (for railway trains), city (for all types of city vehicles: cars, trolleybuses, trams, metro, as well as pedestrians), pedestrian (for pedestrians only), combined (for cars and railway trains), special (for pipelines, power cables, etc.). Based on the type of supports used, moorings are distinguished on rigid supports, which transmit the load from spans directly to the ground through foundations, and on floating supports, which transfer the load to the water (floating moorings on pontoons or barges). A distinction is made between fixed bridges (the span structure always occupies a constant position in relation to the supports) and movable ones (for the passage of ships, a special movable span is arranged - with the halves of the span structure rotated relative to the supports in the vertical plane or the span structure raised to the required height). Drawbridges are built when it is impossible or economically unprofitable to raise the level of passage above the river to a height sufficient for the passage of ships. A significant drawback of such rivers is the inevitability of interruptions in movement along them and along the river. Depending on the main The materials used are wooden, metal, steel-reinforced concrete, reinforced concrete, concrete and stone. The determining factor is the material of the span, therefore, for example, metal structures include metal ones. span structures, regardless of what material the supports are made of. The type of material significantly influences the structural form of the bridge's span and the method of its construction. According to static In the scheme of spans, spans are distinguished (Fig. 1): beam - split, continuous and cantilever; arched - with different levels of the roadway; frame, hanging and cable-stayed; combined, in which various combinations of systems of the first two groups of bridges are used.

Rice. 2. Types of bridges according to the level of the roadway: a – driving on top; b – driving at the bottom; c – riding in the middle.

Rice. 3. Main characteristics of the bridge: 1 – approach embankment; 2 – embankment cone; 3 – abutment; 4 – span structure with ride on top; 5 – span structure with ride below; 6&…

Based on the level of the roadway, they distinguish between vehicles with driving on top (the roadway is located at the upper level of the superstructure; Fig. 2, a), below (the roadway is at the level of the bottom of the superstructure; Fig. 2, b), in the middle (the roadway is located in the middle-height part of the span; Fig. 2, c). The position of the roadway significantly influences its design and the conditions for fitting the street into the landscape. So, when driving low in the cross section of the span, only 2 widely spaced chapters are used. beams or trusses, which complicates the roadway. The system of connections to ensure the stability of the upper chords of the trusses is also becoming more complex. However, a span structure with a ride below is often preferable from an architectural point of view, especially in flat areas, since it has a significantly smaller structure. height compared to a superstructure with a ride on top. Based on the location of the spans relative to the high water horizon, bridges are divided into high-water (spans are located above the river at a level that allows the passage of flood waters and ice drift), low-water (spans are flooded when high waters pass through, usually these are temporary bridges) and underwater (spans). buildings are located under water at a depth that allows vehicles to wade, they are used to ensure the secrecy of their position and increase their survivability during military operations). Based on the width of the roadway, M. with different types are distinguished. number of lanes in both directions. The number of traffic lanes (2–8 or more) depends on the category of road or highway on which the motorway is located. By length, motorways are divided into small (up to 25 m), medium (25–100 m), large (more than 100 m, and also less than 100 m long, but with one of the spans more than 60 m) and extra-curricular, which include structures with a length of more than 500 m or with one of the spans more than 150 m. These are, as a rule, cable-stayed, suspended, frame or arched ones. with 4 or more lanes.

The design solution of the river depends on the width, depth, and flow speed of the watercourse, the type of soil at its bottom and in the floodplain, ice flow conditions, and navigation requirements. Basic parameters of the machine, established during the design process, taking into account its purpose and location conditions (Fig. 3): length - the distance between the beginning and end of the machine, measured along its axis [beginning (end) of the machine - the first (last) along the course mileage counting point is the point of intersection of the line connecting the ends of the abutment openings or other visible structural elements of the abutment, or the span, with the M axis, without taking into account the transition slabs]; hole M. – horizontal dimension between internal. the faces of the abutments or the cones of the embankment, measured at the calculated high water level with the exception of the thickness of the intermediate supports, is determined by the hydraulic. calculations; M. height - the distance from the level of the roadway along the M. axis to the level of low water; free height under the sea - the distance between the bottom of the spans and the high water level or the calculated navigable level (if there is navigation); support height - the distance from its top to the ground; construction height of the span - the distance from the surface of the roadway to the lowest parts of the span; design span – the distance between the axes of the supporting parts of the span on adjacent supports; M. width – the clear distance between the railings; span width - the distance between the axes of the outermost main beams or trusses; width of the roadway – distance between internal edges of safety strips; the width of the driving surface, or the clearance of the passage, is the distance between the fences; high water level (HWL) – the highest water level in the river at the bridge crossing site, which is determined based on long-term hydrometric data. observations with different degree of security for M. on the roads, various. categories; design navigable level (RSL) – the highest water level in the river during the navigable period (usually slightly below the water level); Low water level (LMW) - cf. water level in the river during the period between floods.

The prospects for the development and improvement of bridges are usually determined by the need to increase their spans, the widespread introduction of high-strength materials, the creation of new structural forms and calculation methods, the use of new methods of construction, as well as the formulation and solution of ambitious tasks (for example, plans for the construction of highways across the Bering and Gibraltar straits).

Spiral

Photo: Jakob Montrasio from Saarbrücken, Germany, CC BY 2.0, via Wikimedia Commons

This type of structure crosses its own path and is useful on steep slopes. The structure rises in a steady curve until it closes the loop, passing above itself as the height increases, allowing vehicles to gain altitude over a relatively short horizontal distance.

It is a better alternative to zig-zag roads to avoid stopping vehicles and changing direction when going up or down. The same design is typical for many multi-storey car parks.

Bridges are widely represented in the folklore of different peoples of the world. For example, in Russian fairy tales there is a Kalinov bridge thrown across the Smorodina River. It is believed that it connects the world of the living and the dead. In the Scandinavian sagas, there is a mysterious bifrost - a “trembling bridge” that connects the heavenly city of Astrad with other territories and worlds. The TopCafe editors ask you to add in the comments to the article what other types of bridges you would like to see here.

Classification of bridge structures

Types of bridges can be classified according to several criteria:

• according to the main purpose of use;
• constructive solution;
• building materials;
• depending on length;
• by service life;
• depending on the operating principle.

Since a man threw a tree from one bank of the river to get to the other, a lot of time has passed and a lot of effort has been put into the construction of engineering structures. As a result, different types of bridge designs emerged. Let's take a closer look at them.