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Bridges made of wood and stone. We make pontoons with our own hands "Pontoon bridge" in books

05.08.2023

Bridges are very complex structures. Some of them take many months and years to build. Pontoon bridges differ significantly from other types. Not only can they be built quickly. They are also quickly removed from the river.

general information

Building bridges is an incredibly complex process that often takes a long time. The construction of a new crossing is always associated with overcoming obstacles, achieving new boundaries and goals, new discoveries and accomplishments. Depending on their design, bridges can be arched, beam, hanging, cable-stayed and pontoon.

The first four of these are quite complex structures that require incredibly accurate load calculations and engineering solutions for erection. But there is one type of bridge that does not fit into this description at all - pontoon bridges. These crossings can be erected in a matter of months and just as quickly dismantled and removed.

The history of the emergence of floating bridges

It is believed that floating or pontoon bridges are one of the most ancient types of military crossings. According to historical facts, the first such crossings were built as early as the fifth century BC during the Persian battles across rivers and other bodies of water.

During the time of Julius Caesar, soldiers constantly used pontoon bridges to cross the river. To do this, they simply built a raft along the river bank, the length of which was equal to the width of the river. While it was being built, its initial and final parts were fixed. And when the length of such a raft became sufficient to cross the river, the final part was detached, the current turned the bridge across the river, and the soldiers rushed to the neighboring bank.

Over time, the design of such crossings has changed and improved. The length of the bridges can also be different. For example, in 1785, a pontoon bridge based on rafts was built in a little less than three days. And in the city of Sevastopol, a bridge about a kilometer long was created, which played an important role during the battle. Thanks to him, the soldiers were able to make a retreat through the bay. In times of all great battles and wars, such crossings played an important role.

What are pontoon crossings in the modern world

Today, such crossings are used not only for military purposes, although this is also very often the case. Most often this type of crossing is used:

as a military pontoon bridge for crossing troops;
if you need to transport people and equipment on a self-propelled pontoon;
as a platform for landing helicopters on the water;
for storage and transportation of aircraft by water;
as a permanent crossing on rivers where there is no strong ice drift;
as a temporary structure that serves as a crossing while the main bridge is being reconstructed or repaired;
as auxiliary structures to ensure the breaking of the axes of supports, the supply of materials during the construction of bridges.

Also, quite often there are cases when floating bridges are made for the needs of the Ministry of Emergency Situations.

What can be pontoon crossings

Bridges based on floating pontoons are not much different. The difference may be in the material from which the pontoons themselves are made, and in the way they are fixed to each other. The basis of all floating crossings are modular pontoons. It is also customary to separate three main systems of such bridges:

split;
articulated;
continuous.

The difference between these systems is the way the modules or spans are secured along the entire length of the bridge. Moreover, each of these systems is tested for strength and reliability in different ways.

Pontoons, in turn, can also be different. Their main difference is the size and material from which they are made. Now the most common types of pontoons are:

plastic;
aluminum pontoons;
steel pontoons.

Metal pontoons have two types. They can be with hollow boxes, which ensures their buoyancy, even if one of the boxes is depressurized. To create the second type, boxes are used that are filled with polymer in the form of foam. In this case, you can save on metal, while not reducing the buoyancy. Such steel pontoons are mainly used for transporting combustible materials such as oil.

pros

If we compare pontoon crossings with other types of bridges, we can note an impressive number of advantages of the former:

first of all, it is worth noting that pontoon crossings are built very quickly at relatively low material costs;
the construction of bridges often depends on the depth of the river and the properties of the soil that is at the bottom of the river; for pontoon crossings, these indicators are not important;
these crossings also have such an important property as mobility.

Minuses

Of course, in addition to advantages, pontoons also have disadvantages, which are also many. These include:

the need for constant assessment and monitoring of the state of the connections of the bridge parts;
in case of strong current and waves, especially in certain seasons, the use of pontoon bridges can be problematic, in some cases, if the current speed is more than 3.5 m/s, the use of these bridges is not recommended;
since deformations of the bridge occur under load, the speed of movement on the bridge should be sufficiently low (for vehicles from 10 to 30 km);
floating bridges block the river, which, in turn, makes it impossible for ships to pass.

A separate drawback is the deformation of the bridge in the autumn-winter periods during the movement of ice. There are frequent cases when floating bridges are demolished by ice. Therefore, during periods when frost sets in and ice floes begin to form on the river, which can harm the crossing, the pontoons are usually removed.

For example, a large pontoon bridge was made on the Biya River. Biysk is divided by the river into two parts, and to get to the other side, it is most convenient to use this bridge. But during the winter months, when temperatures drop, the bridge is removed as the first ice begins to form, which could damage the bridge. After that, the bridge can be installed only when the water in its area is completely cleared of ice. The obvious disadvantage of such bridges is the dependence on weather conditions. In this case, until the ice is completely on the river, the bridge will not be installed back.

Pontoon bridge as a crossing of military forces

As mentioned earlier, pontoon crossings were used in ancient times by the military during battles. But if earlier materials such as wood and fabrics were mainly used to build them, today the design of the pontoon has been modernized.

With the development of industry and science, new materials began to be used to build such crossings. Now military pontoons are built mainly from plastic modules. Plastic has advantages over wood and metal. Plastic pontoons do not rot, besides they are elastic and deform much less. They are also easy to assemble and disassemble. The assembly and disassembly process takes a minimum of time, which is important during military operations. Another advantage of modern military plastic pontoons is the affordable price.

Is the pontoon crossing safe?

In the modern world, it is impossible to say that this or that thing is completely safe. However, you can minimize the chance of any unpleasant consequences if you fully follow the rules of operation.

Floating pontoon bridges are truly unique structures that help solve numerous problems of crossing water bodies, not only for people, but also for cars. Subject to all the rules and constant maintenance, such a bridge can last up to 30 years.

The main problem of such bridges is seasonality. This applies to those rivers where, with the arrival of low temperatures, ice floes begin to form on the surface and their current carries them to the bridge. In such cases, so that the bridge is not damaged, it should be removed for a while until the ice is gone. In general, pontoon bridges are safe and serve for a long time without any problems.

Köthe Rainer bridges

What is a floating or pontoon bridge?

What is a floating or pontoon bridge?

In 490 BC. e. in Marathon, located near the ancient Greek capital of Athens, the famous battle took place. After long wars, the Greeks finally managed to defeat the Persians, whose army was led by King Darius from the Achaemenid dynasty.

The army of the Persian king Darius crossed the Bosporus over the bridge laid on the moored ships drawn side by side.

At this time, there is the first ever mention of a remarkable technical achievement. In 493 BC. e. the Persian king Darius made a campaign against the Scythians, ferrying his army across the Bosphorus at the narrowest point of the strait, where the width was 700 m. He did this along the first floating bridge: a wooden deck was laid on moored ships fastened side to side. Less fortunate was the Persian king Xerxes, who 13 years later set out to cross in the same way through another strait - the Hellespont (now the Dardanelles). A sudden hurricane swept the ships and destroyed the almost finished bridge. Enraged, Xerxes ordered the builders to be beheaded and the sea to be punished - flogged! A second bridge was built from 700 ships tied with ropes and put on heavy anchors. The roadway was made of boards covered with packed earth and with a barrier on the sides to prevent shy horses from falling into the water. It is believed that a huge army crossed this bridge - 700,000 horse and foot soldiers, but, despite this, Xerxes was still defeated in the battle with the Greeks. Many commanders used bridges supported by ships or pontoons - simple floating boxes - to quickly transport a large army across a water barrier. The Carthaginian commander Hannibal crossed the Rhone in this way, Alexander the Great crossed the Asian river Oxus, and the Roman emperor Caligula ordered a pontoon bridge to be built in the Gulf of Naples, only to boast that he “ride a horse across the sea.”

Floating, or pontoon, bridges were also built for peaceful purposes, if there were not enough funds to build a permanent strong crossing. Thus, at the beginning of the last century, bridges across the Rhine appeared near Karlsruhe, Speyer and Cologne, which were even used for rail transport. However, such bridges needed to be drawn up regularly to allow the passage of ships traveling along the river, they suffered so much from severe floods and ice drifts and were eventually replaced by permanent bridges.

author Antonov Boris Ivanovich

Atamansky bridge The bridge is located in the alignment of Kremenchugskaya street and Glukhoozerskoye highway. It received its name from the nearby barracks of the Life Guards Atamansky Regiment (Atamanskaya Street, 2). In 1853, the construction of the barracks of the Guards Cossacks on Obvodny