Pontoon Bridge Park: how military pontoons work. Floating, pontoon bridges What does a pontoon bridge look like

4.6. “We built a pontoon bridge and immediately the columns went…” From the Austrian soldier's song “The Brave Knight Prince Eugene” The conversation was held by Tuga, who was planning a new retreat: to leave with

The advantage of pontoon bridges is their transportability (both by water and by land in a disassembled state), the speed of installation. The disadvantages include the creation of problems for navigation, low bearing capacity, dependence on wind, waves and water levels, the impossibility of operation during the period of ice drift and freeze-up. If used incorrectly, pontoon bridges can “float away”, as was the case in 2005 in the city of Novokuznetsk with a bridge across the Kondoma River.

One of the famous pontoon bridges of ancient China was the "Scarlet Bird Floating Bridge" (Chinese 朱雀浮航, pinyin: Zhūque fúhang, pall. : zhuque fuhang), about 125 meters long and 15 wide, which led to the central gate of Jiankang across the river Qinhuai(Chinese 秦淮河, pinyin: Qinhuai he).

Story

The first pontoon corps in world history was commanded by the Austrian engineer Carl von Birago, who personally developed the pontoon system, which was soon taken as the basis by all major European armies.

In the 18th century, floating bridges (called pontoons) were built by military teams. The floating supports were flat-bottomed boats, boats or large boats. A flooring was laid on them - a span structure. The bridge was secured with anchors and shore guy lines against the current of the river so that it would not be blown away. To maintain the bridge, a special military team was required, which spent a lot of time and effort.

Pontoon bridges in Russia

The longest pontoon bridge in Russia at that time, about 750 meters long, connected Aspen River (a suburb of Khabarovsk) and Bolshoi Ussuriysky Island. The pontoon bridge connecting the island with the right bank of the Amur channel was built in 2002 and operated from May to October, it was used for the passage of agricultural machinery and vehicles. Before the bridge was built, communication with Bolshoi Ussuriysky Island was provided by a ferry crossing. In winter, the passage to the island was carried out on ice, and during the ice drift and freeze-up, the island remained cut off from the "mainland". In order not to violate the work schedule of Russian and Chinese courts, the pontoon bridge was raised once a day. On October 23, 2013, the capital bridge across the Amur channel was opened, the pontoon bridge was dismantled. The title of the longest pontoon bridge in Russia passed to the newly built bridge across the Tom, 720 m long, in Yurga, Kemerovo region ( 55°44′34″ s. sh. 84°56′29″ E d. /  55.7429° N sh. 84.9415° E d. / 55.7429; 84.9415 (G) (I)).

• Pontoon (village in the Kolpinsky district of St. Petersburg)

Write a review on the article "Pontoon bridge"

Notes

An excerpt characterizing the Pontoon bridge

Floating bridges, depending on their floating supports, can be raft, pontoon and pontoon. Raft bridges are now very rare due to their low carrying capacity. Pontoon floating bridges, the supports of which are hollow closed boxes (pontoons) made of wood or metal, are inconvenient in operation due to the complexity of their inspection and repair. The most common are pontoon bridges with a large carrying capacity on floating supports in the form of barges or pontoons.

A feature of floating bridges is the seasonality of work. With the onset of freeze-up, they are removed to the backwaters or to the shore, protected from ice drift and floods, and if they are exploited during the winter, then they are taken to backwaters for the period of spring ice drift. Floating bridges require large expenses for the maintenance and repair of the floating part. The main element of a floating bridge is its floating part in the form of floating supports and superstructures (buildings) resting on them. The floating part usually covers the main part of the width of the river, on which, at the lowest water level, a margin of 50 cm is provided from the bottom of the river to the bottom of the support when passing vehicles over the bridge. The floating part of the bridge is usually formed from separate links having one or more floating supports with a lining, and is fixed with anchors against drift by water and wind. For the passage of ships, a drawbridge span is arranged, consisting of one or more links. The coastal part of the bridge is a flyover of the simplest design in sections of the river where the depth is insufficient for the construction of floating 262 pores. Usually the coastal part adjoins the exits to the shore. The floating and coastal parts are connected by an ice drift, which changes its level depending on fluctuations in the water level in the watercourse.

Although the construction of floating bridges is simpler and cheaper than permanent bridges, their operation is more complicated and involves significant materials and especially labor costs. Floating bridges require round-the-clock duty of a team of workers to ensure traffic safety and timely elimination of all defects, damages and malfunctions, as well as to ensure normal navigation on the river. Constant supervision is needed for all elements of the bridge - floating supports, anchoring devices, lining, span structures of transitional coastal parts and approaches to the bridge.

The main attention in the maintenance of floating bridges should be given to floating supports. By daily inspection of the supports from the inside and outside, the condition of the support and the amount of water inside are checked. The normal amount of water in the support should not exceed half the height of the diggings. Excess water must be pumped out in a timely manner. In case of damage to the supports and the appearance of a leak, the causes must be determined and eliminated.

In wooden floating supports, defective places (slots or holes) are repaired with caulking or wooden plugs made of non-penetrating wood. If the defective places are not immersed in water, they are caulked from the outside from a boat or other floating craft. Slots and holes in the skin, located below the water level, can be sealed from the inside.

To protect the floating supports from decay or rusting, it is necessary to ensure ventilation of their internal cavity, eliminating hatches in the pontoons. All longitudinal trusses, frames, transom frames, as well as load-bearing elements of the internal structure, must be inspected daily, checking the density of interfaces and connections, and any defects found should be immediately eliminated. When rot appears, the affected wood is removed and replaced with healthy, impregnated with an oily or water-soluble antiseptic that is difficult to wash out.

Strict requirements for the maintenance of floating supports force the operation service to keep on the shore or on the water, not far from the floating bridge, spare floating supports, and, if possible, individual links of the floating bridge.

To ensure the necessary position of the floating part of the floating bridge (from drift or wind) during operation, the floating supports are fixed with ropes or cables for ghouls, anchors, pile bushes or trees on the shore. Usually floating supports are fixed on the upper side to prevent them from being carried away by the current. With a weak current of the river, where the demolition of the floating part from the wind in the direction opposite to the current is possible, it is also fixed from the downstream side. Floating supports, located not far from the shore, are fixed to large tree trunks or bushes of piles driven on the shore, and the rest of the supports are anchored. On small rivers, it is sometimes possible to fix the floating part without the use of anchors.

The anchoring ropes must have an angle to the direction of the water flow of no more than 35°. The distance from the anchor to the floating support (Fig. 156) should be 10 times the maximum water depth in the river. Ropes are used, as a rule, steel, hemp due to a very short service life - only in exceptional cases. The ropes are fixed to the anchor and the winch installed on the floating support.

If the anchor is pulled off its bridge, then the floating part of the floating bridge is bent. With a slight pulling of the anchor, the rope is pulled up with a winch, and with a significant one, it must be thrown back into the design position. In the case of a systematic change in the position of the anchors, their number has to be increased or replaced with heavier ones.

The work on the maintenance of the transitional parts includes the constant provision of a smooth entry and exit from the floating bridge. With an amplitude of fluctuations in the water level in the river up to 1.5 m, the transitional part, as a rule, consists of one span structure, hinged at one end to the extreme coastal trestle part, and the other end to the floating part of the bridge. The transitional part in this case is a simple beam system with a span of up to 6-8 m. The ends of the runs usually rest on the extreme floating support, causing it to be overloaded and significant draft. Therefore, the extreme floating support (pontoon or pontoon) should have a greater carrying capacity than the rest.

Rice. 156. Scheme of fixing a floating bridge on a wide river

Often, floating bridges are built across large high-water rivers, where the oscillation amplitude can exceed 5 m. In these cases, it is necessary to arrange transitional spans with through farms or rely on special pile supports (Fig. 157), equipped with lifting devices (hoists or jacks). With the help of these devices, by raising and lowering the transition parts, they provide a smooth entry and exit from the bridge.

The operation service regularly monitors the junctions of transitional spans with floating and permanent supports. In the event of a change in the water level, the lifting beams are respectively raised or lowered with hoists or jacks, giving the transition part an external slope (not more than 80 ° / oo) - The greatest difficulties in maintaining the transition parts of floating bridges arise in the spring when ice drift passes. Before the ice drift, the floating part and the spans of the transitional parts are removed to a safe place, while the tower supports of the transitional spans remain and are protected from ice drift. There are three known options for the preservation of the supports of the transitional spans. With a relatively weak ice drift, the tower supports are protected by ice cutters, and with a strong one they are arranged collapsible. In the latter case, before the passage of ice drift, the upper part of the supports is dismantled and, together with lifting devices, removed to a safe place. The remaining part of the support must be such that it is not damaged by the lowest ice drift.

Sometimes the transition parts are arranged with two independent entrances with a difference in height of about 1.5 m. The arrangement of several entrances makes it possible to reduce the length of the transition part to one span and simplify its design.

Rice. 157. Schemes of the multi-span transitional part of the floating bridge and the profile of water level fluctuations.
A - amplitude of level fluctuation

Moving the entire floating part from one entrance to another when the water level changes does not present any particular difficulties - the entire floating part is pulled upstream or downstream. If the floating support is a floating support or a pontoon, then the height of the dry side, i.e. the height from the water level to the top of the floating support, must be at least 50 cm. Therefore, the operation service must have a schedule for passing live loads on the bridge, taking into account their weight and dimensions.

When passing cars whose weight is close to the norm, it is necessary to strictly control the distance between these cars, and also to ensure the passage of single especially heavy cars in the middle of the bridge in one-way traffic. After the passage of heavy vehicles, it is necessary to inspect all bridge structures. On floating bridges, sudden braking, as well as the deployment of vehicles, are prohibited. To regulate traffic on the floating bridge, there should be barriers on both banks and the duty of the most experienced workers should be established.

For quick and clear wiring of the span and its return after the passage of ships, it is necessary to equip the adjustable device with electric motors of sufficient power. Electric motors are installed on the shore in a special room or on the first floating support of the draw span.

Usually, with the help of one mechanism, the wiring and the reverse installation of the adjustable link are made (Fig. 158). In this case, a traction mechanism is installed on the shore, consisting of an engine, two drums rotating in different directions and two cables (from the drums) connected to the first floating support of the draw span of the floating part of the bridge. Sometimes two traction mechanisms are installed on the first floating support of the adjustable

link, while one works on the wiring of the bridge, the second - on the tip.

In some cases, when the intensity of traffic on the highway and the river is small, the bridge is drawn and its input is provided with the help of a gate installed on the first floating support of the adjustable link.

In most cases, floating bridges are operated when the river is ice-free, and in winter they are bred and removed to a place safe from spring ice drift, for example, in backwaters on the river in which there is no ice drift, or the water level in which is 25 cm below the draft of the floating support from their own weight, or they are pulled ashore above the level of the largest ice drift. In this case, the movement of vehicles in the winter period is carried out along the ice crossing.

Rice. 158. Scheme of wiring and pickup of a span of a floating bridge: 1 - block; 2 - winch; 3 - draw span

With the approach of cold weather, as well as before the passage of floods and ice drift, it is necessary to organize, taking into account the characteristics of the river regime, observation posts that have a connection with the bridge. More often, such observation posts to obtain information about the movement and accumulation of ice, the appearance of sludge and fat are installed upstream by 5-10 km, and sometimes even further.

With a weak current, the sludge easily accumulates near the pontoon bridge, freezing to piles, floating supports, ropes, clogging the free section of the bridge, forming blockages, creating additional load and thereby reducing the carrying capacity of the bridge. The resulting jams and ice jams hamper the riverbed and increase (sometimes by several times) the pressure on the floating supports, damaging them.

During the period of the first frosts, thin ice forms on the river from small pieces (lard) moving with the flow (autumn ice drift). Thin young ice damages the plating of floating supports, easily cuts even steel ropes with its edges. Salo, especially with a weak flow of the river, freezes to the floating supports and creates a risk of congestion.

Special measures are needed to keep the bridges in good condition.

When sludge, fat, sneshura appear on the river, it is necessary to systematically (with shovels, crowbars or ice picks) clean the sides and bottoms of floating supports, anchor ropes from freezing ice. In some cases, when large ice floes appear, blasting is carried out at a distance that guarantees safety. To protect the side plating of wooden floating supports from cutting through with thin ice, their additional lining with boards is effective either only from the bow or along the entire perimeter of the floating support. In this case, additional skin is given within the limits between the waterlines corresponding to the unloaded and maximum loaded state of the bridge. To pass accumulations of sludge, lard and sneshura, as well as large ice floes, the size of which exceeds the clear distance between the floating supports, it is necessary to breed the spans of the floating part of the bridge.

If not all floating supports enter the drawbridge, then to protect the remaining ones, it is necessary to install floating booms to direct the ice floes into the opening of the bridge. Booms, arranged from single or paired logs, must be securely fastened.

During the freezing period, the water level fluctuates. The lowering of the level causes the ice to sink, its separation from the coast, and if at this time the floating supports are frozen into the ice, they can be crushed. A sharp fluctuation in ambient temperature can also lead to crushing of floating supports. To prevent the destruction of floating supports during this period, it is necessary to systematically chip the ice around the supports and anchor ropes during the entire winter period.

To increase the productivity of work on breaking ice, pipes with holes for air passage are laid at the supports along the bottom of the river. Air through the holes enters the water, rises and breaks the ice. This device has great performance.

There are known cases of floating supports freezing into ice on large navigable rivers, where the water level is most stable, and the floating supports are metal. During the operation of floating bridges with frozen-in floating supports, it is necessary to ensure timely ice fragmentation around the floating supports with the onset of spring thaws.

Purpose - a floating drawbridge over navigable rivers classified as "P" of the River Register of the Russian Federation.

The sections afloat are kept from the pressure of the current by Hall anchors of 1000 kg each, the cable is stuffed with manual capstans. The layout of the bridge afloat is carried out by a boat.
Carrying capacity (mass of passing vehicles) - 28 tons
Traffic is one-way, the width of the carriageway of the bridge is -3.5 m
Width of pedestrian sidewalks - 2х0.75 m
Railing height - 1 m
Draft without load - 0.41 m
Draft at maximum load (28 tons) - 0.7 m
The width of the ship's passage is 40-80 m.
Vehicle speed - 10 km/h.
Maximum wind speed 15 m/s (7 points on the Beaufort scale)

On the end pontoons, manual spiers ShR-2 with a force of 700 kgf and 2 cast bollards are installed. The roadway in cross section consists of 4 welded beams 1450 mm., Connected along the length by a channel 27 with a step of 900 mm. On beams a flooring from sheet S=8 mm. width = 5100 mm., at the ends (in width) it is edged with a channel 27. The roadway for vehicles is marked with a constructive strip bulb 16 at a distance of 3500 mm. symmetrical across the width of the bridge. For every 50 m of the bridge length, 8 lamps of 60 W each are installed. Anti-slip points are welded on the flooring of the carriageway.

You are a happy owner of a house by a pond, you probably imagined a bridge in the middle of a lake, where you can go fishing or just sit in calm weather, enjoying the smoothness of the water or the rustle of the surf. Of course, you can build a permanent concrete bridge, or you can resort to a more romantic way and create a floating bridge. Such a pier is based on pontoons, which help the pier stay on the surface. We make pontoons from barrels with our own hands.

The only downside would be the high price. If you want to save the family budget, you can use plastic barrels.

We will understand in detail the process of making a floating pier from barrels with our own hands. To create a berth, we need materials and construction tools:

1. There are four plastic barrels, you can use metal ones, for lack of the first.
2. Wooden boards or moisture resistant plywood.
3. Beam 10 cm.
4. Beam 5 cm.
5. Rope.
6. Epoxy resin.
7. Alkyd paint.

To create a pontoon, wood is better to choose hardwood. It does not rot so much when in contact with water, which will significantly extend the service life. If you could not find such bars, you can opt for oak or pine. All materials must be primed and painted. When choosing plywood, the ends are coated with pre-prepared resin. If you chose metal barrels as barrels, they must also be carefully primed. And then paint with anti-corrosion. It is better to collect the pontoon near the water, so as not to drag the finished structure:

• So, initially we are preparing a square, one side should be 2.5 m. If you follow this size, barrels will fit perfectly here. For the manufacture of the frame we use logs. To get an even square, put even bars in the corners or measure the diagonals of the square;
• Next, we prepare two-hundred-liter barrels, we need four pieces. As a rule, finding such is not at all a problem, it remains to process them;
• We cover the barrel with paint, and then coat the cork with sealant or silicone. If barrels are not available, they can always be purchased at a hardware store. When buying, give preference to plastic products;
• When the barrels are ready, we construct the inner skeleton of the pontoon. To do this, you need to place barrels at the corners of the square. The dimensions of the barrels allow this to be done without problems. We need to strengthen the barrels, inside we install the bars, so that one side fixes the barrel, and the other rests on the frame. For the strength of the structure, you can fix the barrels with two more bars. They must be placed on both sides of the barrel, pressing it tightly. The bars are attached to the base with screws. Next, the barrels are fixed with ropes. Six holes are made for each barrel. The structure is then reversed.

Further assembly of the pontoon is carried out already on the water. The frame of the upper side is sheathed with the material you have chosen to create the floor.

The most common way to create a pontoon will be pontoons made from bottles:

• To get started, you need to collect a huge number of plastic bottles. Well, if all the bottles are two-liter, you will need approximately 350 pieces. This amount is necessary if the bottles are two-liter and the berth is small. If the bottles are smaller, you will need more. It is better if the bottles are not even, then it will be much easier to tie them;
• Before starting work, it is necessary to check the tightness of each of the bottles. Your goal is to create a large pier, it must be made from several small ones;
• To create a pontoon from plastic bottles, you need bars for the frame, ropes and bags. Bottles must be placed in each of the bags; about thirty bottles are placed in a regular bag. They need to be folded vertically in two layers. The weight that the berth can withstand depends on the number of bags;
• To install bags, fasten them to the frame with bags. It is necessary to place bags according to the size of the berth. Covering is best done from boards. It is better to fasten the pier to piles or with the help of anchors.

Also using this method of creating pontoons, using car cameras and foam.

Video about pontoons on plastic floats

Video about a homemade pontoon from plastic bottles