Bridge to Russian island description. The bridge to the Russian was called a "useless structure for $ 1 billion
The construction of the bridge to Russky Island is carried out within the framework of the subprogram "Development of the city of Vladivostok as a center of international cooperation in the Asia-Pacific region".
The bridge to Russky Island will be one of the largest cable-stayed bridges in the world, with a central span of 1,104 meters that will set a record in world bridge building practice.
This bridge will have both the highest pylon and the longest shrouds.
Bridge parameters:
The design of the bridge crossing is determined based on two main factors:
- The shortest distance along the water area at the intersection of the bridge is 1460 meters. The fairway depths reach 50 meters.
- The bridge construction area is characterized by difficult climatic conditions: temperature difference from -31 to +37 degrees, storm wind speed up to 36 m/s, storm wave height up to 6 meters, ice formation up to 70 centimeters thick is observed in winter.
Construction of reinforced concrete pylon
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Under each of the two 320-meter pylons of the bridge, 120 bored piles are laid (on the M-7 pylon from the side of Russky Island - with a non-removable metal shell). Concreting of the pylons is carried out using the original self-climbing formwork in 4.5-meter grips. A crane is used on the first three grips, then the formwork begins to move independently due to the hydraulic movement of the modular elements. The bridge pylons are A-shaped, so the use of standard formwork is not possible. A separate set is mounted for each pylon. The transition according to the types of section is carried out at the level of jumpers at the levels of 66.26 and 191.48 meters. The use of self-climbing formwork makes it possible to improve the quality and reduce the construction time of monolithic reinforced concrete structures by one and a half times.
At a height of 189 m, the cable attachment zone begins. Installation of cable pairs and concreting of the pylon body will take place simultaneously. Such a technological solution drastically reduces construction time.
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Installation of the central span
The structure of the superstructure has an aerodynamic cross section for absorbing loads from squally winds. The configuration of the span section was determined on the basis of aerodynamic calculations and optimized based on the results of experimental processing of the scale model at the detailed design stage.
Welded field joints are used for longitudinal and transverse joints of the cover sheet of the orthotropic slab and the lower ribbed slab. For the joints of the vertical walls of blocks, longitudinal ribs, transverse beams and diaphragms, mounting joints on high-strength bolts are used.
Large-scale sections for the installation of the central span in specially designated "windows" are delivered by barges to the assembly site and are lifted by a crane to a 76-meter mark. Here, multi-ton elements are joined and shrouds are attached to them.
Cable system
The cable-stayed system assumes all static and dynamic loads, the very existence of the bridge depends on them. The guys are maximally protected from natural disasters and other adverse effects and are designed for the entire service life of the bridge.
The high strength, endurance, and corrosion resistance of the shrouds ensure an estimated service life of at least 100 years.
For the central span, an improved, so-called “compact” PSS system was used with a denser arrangement of strands in the shell. The compact configuration of the cables with the use of a shell of a smaller diameter helps to reduce the wind load by 25-30%. At the same time, the cost of materials for the pylon, stiffening beams and foundations is reduced by 35-40%.
The PSS cables consist of parallel strands with a diameter of 15.7 mm, each of which consists of 7 galvanized wires. Guys include from 13 to 85 strands (strands). The length of the shortest cable is 135.771 m, the longest is 579.83 m. The protective sheath of the cable is made of high density polyethylene (HDPE) and has the following properties:
- resistance to ultraviolet rays;
- environmental resistance in climatic conditions Vladivostok (temperature range from -40С to +40С).
How it all started
The issue of building a bridge that will establish regular communication between Vladivostok and Russky Island was raised in Tsarist Russia. All this time, the locals had only two possible options crossings to the mainland: by ferry, as well as walking on a layer of ice covering the strait in winter.
The first engineering project of the Russian Bridge was developed back in 1939. It was assumed that the structure would be wooden and would connect Cape Tokarevsky and Helena Island. Later attempts to build a structure (70s, 80s) remained in the development stage.
The last time the need to build a bridge across the strait was discussed was in connection with the preparations for the APEC summit. As part of investment project Russky Island was supposed to be turned into a major center of international cooperation, and for this it was necessary to establish transport links with the mainland.
Despite the fact that the upcoming event was accompanied by another economic crisis, the government decided not to abandon the decision. Moreover, the construction of such a grandiose object as the Russian Bridge was supposed to give a tangible impetus to the revival of the Far Eastern region.
Design and construction
In 2007, the research and production association "Mostovik" received permission to create a project for the future bridge. Among several options proposed by the engineers, preference was given to the cable-stayed design. The foundation for the future construction was to be pylons, which would "bear" the main weight of the bridge. A well-thought-out system of cables (cables) should have been responsible for the distribution of the load. Metal cables attached to different points pylon in the form of a fan, giving the structure maximum stability.
The main difficulty in this was the too short time allotted for the design of the Russian Bridge. It was necessary not only to develop a site plan, but also to take into account such negative factors as unstable weather conditions, high seismic activity in the region, as well as seasonal temperature fluctuations. In addition, we had to take into account the inevitable bulk of ships passing through the strait, and at the same time the half-meter ice crust that forms on the water surface in winter. However, despite all the difficulties, the project was fully completed and handed over to construction companies in 8 months, which became a kind of world record.
Work on the construction of the Russian bridge began in September 2008. The construction was entrusted to the general contractor USK MOST, the creation of the cables was undertaken by the French company Freyssinet, and the Russian team of MT Electro specialists took up the lighting project.
Especially to reduce the load on the structure, a special type of cables with a ribbed surface was created. It was assumed that the network of “grooves” applied to the cables would remove raindrops, as well as air currents, thereby increasing the endurance of the Russian Bridge.
The construction of the structure was sometimes carried out in extreme conditions. Sharp gusts of wind, low temperatures - all these negative factors were constant companions of the installation work. As an example, it suffices to cite the fact that the last consoles that were supposed to close the structure were installed at night. Since, under the influence of solar radiation, the parameters of metal blocks can change their characteristics, and maximum accuracy is required for joining the grooves, the work was postponed to night time.
Russian Bridge Records
- The structure has the highest pylons (bearing structural elements) - 324 m.
- Compared to all existing similar structures, the Russian Bridge has the maximum cable-stayed span (1104 m).
- During the construction of the bridge, the longest guys (cables attached to the pylons) were used - from 135 to 580 m.
The total length of the structure, including overpasses, is 3100 m. The length of the bridge itself is 1885.53 meters. On August 29, 2012, the structure passed the strength test with honor, having withstood the devastating pressure of the Pacific Typhoon Bolaven. And a few days later, on September 2, 2012, the official opening of the working movement on the carriageway of the Russian Bridge took place, which was attended by D. A. Medvedev. The solemn event was timed to coincide with the day of the city, marking it with festive fireworks.
Grace incarnate
Despite the fact that the main function of the Russian Bridge is a transport connection between the island and the mainland, the aesthetic characteristics of the most modern landmark of Vladivostok can cause genuine admiration. A fantastic view of the structure opens at night when the architectural lighting is turned on. Professionally built lighting creates an optical illusion of flight. The bridge seems to hover over a dark strait.
The futuristic appearance of the Russian Bridge is complemented by the guys themselves. Painted in the colors of the Russian tricolor, they give the composition a special, unique flavor and extraordinary solemnity. To fully appreciate the true power of architectural design, it is enough just to ride from the mainland to the island. Only by driving along the motorway leading through the bridge, you can truly feel the solidity and amazing beauty of this unique structure.
- Initially, three projects were proposed cable-stayed bridge.
- The structure is closely monitored, and its condition is monitored around the clock by satellite systems.
- The image of the Russian bridge can be seen on banknotes with a face value of 2000 rubles.
How to get there
The address of the Russian bridge: Vladivostok, the East Bosphorus Strait, st. Velvet.
The easiest way to get to the main seaside attraction is by bus. Routes No. 15, 22, 29, 74 and 76 go through the Russian Bridge. A more comfortable and, accordingly, more expensive option is a taxi.
Search tags: Photo source:Due to theft and design errors, the bridge is gradually being destroyed.
“A grandiose construction of mankind”, “a masterpiece of design thought” - these are just a few of the enthusiastic epithets that accompanied the construction of the bridge from Vladivostok to Russky Island. Officials and builders patriotically exclaimed: “Finally, we'll piss off all these Chinese and Americans. Our bridge will be the largest, the most beautiful, and it will be built using innovative technologies (which ones and what they are, however, were not specified).
The largest, most modern
This bridge, without exaggeration, can be called the "construction of the century." For example, during its construction, a unique inclined formwork was used to construct the pylon grillage, the length of which was 320 m. The pylon grillage itself was divided into three sections, in each of which a complete concreting cycle took place. The volume of one such site was 9,000 cubic meters of concrete, which in terms of scale is equal to the construction of six monolithic houses with 10 floors. And in terms of the volume of material used, the foundation of the pylon on the island is equal to the whole microdistrict, while the width of the span (steel structure) is 21 m, and the clearance under the bridge is 70 m.
For reference: the bridge to Russky Island is the largest cable-stayed bridge in the world. Traffic on it was opened on August 1, 2012. The bridge was built for the APEC summit, which took place in September 2012, and connects the mainland of Vladivostok with Russky Island through the East Bosphorus Strait. The central span of the bridge with a length of 1104 m is a record in the world practice. The total length of the crossing is 3.1 km, the height above the water level is 70 m.
Metal was stolen by the tons
However, one should not forget that a bridge was being built in Primorye, and in those parts governors and high-ranking officials are often imprisoned for bribes. So at the “construction site of the century”, cunning people decently “warmed up their hands”. Only 4 months have passed since the opening of the bridge, and it turned out that more than 96 million rubles worth of metal structures were stolen during its construction. The suspect is a security officer of the company "Mostovik" Rafael Javadov. He created an organized group, which included workers from the checkpoint, who freely passed certain vehicles, and storekeepers who had free access to the metal. Javadov even purchased special equipment for the removal of the stolen person and appointed a city resident previously convicted of kidnapping as a driver. The stolen goods were handed over to metal collection points in Vladivostok.
The bridge rests on parole
Less than a month passed, and it turned out that due to weather conditions, the outer shell of the bridge guy had "sagged". However, the administration of Primorye, citing specialists, states that these changes will not affect the safety of the facility.
Meanwhile, the former deputy head of Rosprirodnadzor Oleg Mitvol admitted that the bridge guys sagged too much, which corresponds to the 40th or 50th year of operation, that is, "so they could sag in half a century."
Oleg Mitvol believes that initially, at the design stage, the wrong constructive decision was made. He calls for the designers of these structures to be held criminally liable and to reimburse the budgetary costs. “True, I don’t know how they will reimburse the multibillion-dollar costs. In a good way, it needs to be taken apart and redone. It's a disgrace," he says. Oleg Mitvol. And many builders agree with him. They insist that it is necessary to change the approach to construction, especially for such large objects as bridges.
The general contractor was not allowed to the project
Here is how, for example, construction is carried out abroad. First, a project is developed on paper, graphs, in technologies, everything is calculated, and only then we are talking about cash injections. And we first get funding (as a rule, it is state), while the "beaters" often do not even have project documentation, working drawings. When the first funds arrive, an agency is selected to draw the details, the concept, for example, how long the overpass will be, etc. After a bridge is “built” on paper, it is necessary to pass an examination. It is usually formal. Specialists who would understand the subtleties of construction and technology are not present there. Therefore, no one usually thinks about how to build spans, beams, felons. In order to pass the examination, you need to lay down the approximate cost of the project (it is usually greatly underestimated and does not include the cost of technology). When the examination is passed, the work of the designer begins. Moreover, general contractors and contractors do not take any part in the project. They are given a ready-made solution. The contractor starts working on it, and then various “blunders and shortcomings” emerge, for which he is now responsible. And such a "mutual responsibility" exists only in our country, even our neighbors in the CIS do not have such lawlessness.
"Sprinkled with stability"
Vladivostok knows firsthand what such serious errors lead to in the construction of such large facilities. So, in June last year, the section of the new Sedanka - Patrokl highway began to collapse. Stones and soil collapsed onto the garages below. According to investigators, the total damage amounted to almost 1.8 million rubles. And 2 months later, as a result of a landslide, a section of a retaining concrete wall collapsed onto the same route, which leads to the bridge to Russky Island.
“Don't be afraid, it's just that we were sprinkled with a little stability,” joked the locals.
A landslide hit the Sedanka - Patrokl highway
The culprits were quickly found - CJSC Pacific Bridge Construction Company, which is also building a bridge across the Golden Horn Bay in Vladivostok, blamed the designers. Chief project engineer of the road department of the Khabarovsk branch of GiprodorNII Alexey Mikhailov stated that the builders did not make the drainage system, which was in the plan. The designers determined its absence only by looking at the track after the collapse.
They built, built ... and for whom did they build?
The bridge was built, the summit was held - and what's next? It was supposed to open a federal university on the island. But who will study there? Youth and teachers are in no hurry to leave the mainland. “There is not even drinking water there, it is not known in what conditions we will live,” one of the students complains.
Indeed, drinking water is brought to the island in canisters. And it is still unclear when a water pipeline will be built on Russky. In the meantime, water for technical needs is produced by a distiller.
Residents of the island say that heating has not been supplied to some buildings of the future university, it is not even provided for in the project. For example, they jokingly call building No. 7 a “float”, since it was erected at the site of groundwater outlet and its foundation is constantly flooded.
Civilization smells bad
Not so long ago, a representative office of the prosecutor's office was opened on the island in order to simplify the acceptance of applications from disgruntled builders. And the outraged inhabitants of the island do not seem to be heard. They are trying to convince the Crocus company, which built the FEFU buildings, to change the sewerage scheme. According to the project, all sewage discharges after cleaning will fall into the closed Novik Bay, located in the middle of the island. For ecologists and hydrologists, it is obvious - given the volume of discharge, in a couple of years fresh water supplant the sea. The fauna of the bay will die first - fish, delicacy mollusks, holothurians, then algae, seaweed. And then the bay will turn into a swamp.
Representatives of the Crocus company, in their defense, put forward an argument, they say, there used to be a desert here, and we built it up and brought civilization to these desert lands. But local residents such progress is not needed. They want to breathe clean air, not… you know what.
Elena PRYADKINA
The Russian Bridge in Vladivostok is cable-stayed and connects the Nazimov Peninsula and Cape Novosilsky on the Russian Island, separated by the East Bosporus Strait. The bridge appeared as part of the APEC summit in 2012. The Russian Bridge is a complex and unique object in the entire practice of bridge building in Russia and the world.
Building
The construction of the Russian bridge in Vladivostok began in September 2008, although the question of its construction arose at the beginning of the twentieth century. In 1939, the first draft was drawn up, in the 1960s, the second. But both remained unfulfilled. And only in 2008 the final design of the cable-stayed bridge was approved.
During the construction of the bridge, different positions were expressed regarding the expediency of its appearance. Some said that the work was not economically justified, since only five thousand people live on Russky Island. Others insisted that the construction of a bridge to Russky Island would be an impetus for the development of the island, the creation of large economic and cultural centers.
Description
The Russian bridge is one of the most grandiose in the world. One of the reasons for this is that the length of the bridge in Vladivostok on Russky Island – over three kilometers. The roadbed of the structure is supported by diagonal cables. They, in turn, are attached to two pylons, each reaching a height of 324 meters.
The entire structure weighs 23,000 tons. Its spans reach a kilometer. From the top of the bridge, you can see stretched cables painted in the color of the Russian flag. Lanterns are installed along the railings. At the descent from the bridge, one can observe cannons - the remains of the Novosiltsevskaya battery.
Hidden inside each pylon are ladders that lead to viewing platforms, but they are only available to staff watching the bridge, and only occasionally to photographers. From a height of 300 meters, a breathtaking view opens up: endless Pacific Ocean and below Vladivostok in barely noticeable outlines
Technical features
The cable-stayed system of the bridge across the Eastern Bosporus was designed by the best engineers in Russia and abroad. The shrouds consist of 13 to 85 parallel strands, each individually protected against corrosion. The shell is made of two layers: the inner one is made of dense polyethylene, the outer one is thinner.
The decorative shell has a spiral collar - it provides protection against vibrations generated during the simultaneous action of rain and wind.
The Russian bridge was built in conditions of strong winds, a humid climate and sudden changes in temperature. As a result, the cables, thanks to special steel, are able to withstand the temperature range from -40 to +40 degrees, and their service life is up to one hundred years. The aerodynamic section of the structure makes it resistant even to squally winds, which often happen in Vladivostok.
Motion
The bridge to Russky Island allows residents to travel there for the weekend. The building is designed for cars and small trucks.
There are four traffic lanes on the roadway - two in both directions. Drivers who find themselves at a height of 70 meters are breathtaking from the water surface extending below and the shrouds hanging from above. Pedestrians are prohibited from entering the bridge.
Lighting
Lighting equipment for the bridge to Russky Island was completed in early 2013. The main task of the lighting is to create the illusion of a bridge floating in the air and at the same time emphasize its main elements - giant pillars and shrouds painted in the colors of the Russian flag.
Lighting equipment is fixed in such a way as not to create difficulties during operation. Lighting not only highlights the bridge, but also noticeably transforms appearance during the dark hours of the day.
Bridge for tourists
Cable-stayed bridge to Russky Island across the East Bosporus Strait- this is the largest cable-stayed bridge bridge currently built. The central channel span has a length of 1104 m, and the length of the cables is 580 m. The height above the water table (underbridge clearance) is 70 m.
Parameters of the cable-stayed bridge to Russky Island – stroyone
| No. p / p | Main technical parameters of a cable-stayed bridge |
| 1 | Bridge layout: 60+72+3x84+1104+3x84+72+60 m |
| 2 | The total length of the bridge is 1885 m |
| 3 | Total length with flyovers - 3100 m |
| 4 | The length of the central channel span is 1104 m |
| 5 | The total width of the carriageway - 21 m |
| 6 | Number of lanes - 4 (2 in each direction) |
| 7 | Underbridge clearance — 70 m |
| 8 | The height of the pylons is 324 m |
| 9 | Longest / shortest shroud - 579.83 / 135.771 m |
| 10 | Construction cost $1 billion |
The new bridge will connect the mainland and island parts of Vladivostok and will become an important link in the transport system of the Primorsky Territory. The construction of the cable-stayed bridge crossing began in 2008 and ended in July 2012.
Climatic conditions
The builders worked in extreme weather conditions. Wind speed reaches 36 meters per second, storm wind raises waves up to six meters, ice thickness reaches 70 centimeters. The temperature in winter drops below minus 36 degrees, and in summer it rises to plus 37.
Technique in the construction of a cable-stayed bridge
About 320 modern units were involved in the construction of the bridge to Russky Island. For the construction of the pylons, unique Kroll tower cranes with a lifting capacity of 40 and 20 tons were used, capable of growing to a height of up to 340 meters.
During the installation of the channel span structure, Russian-made derrick cranes with a lifting capacity of up to 400 tons were used. To lift the first ten sections on Russky Island, it was mounted in record time.
Flyovers
The approaches to the bridge are overpasses with a total length of more than 900 meters. Trestle supports are rack-mounted, from 9 to 30 meters high. The superstructures are steel-reinforced concrete, consisting of metal boxes with inclined walls and a monolithic reinforced concrete slab.
bridge supports
Bridge supports M1 on the Nazimov Peninsula and M12 on Russky Island are among the most massive and complex in design. Their height is about 35 meters. "First" and "twelfth" perform the functions of transitional supports. They take on the horizontal load from the stiffening beam.
During the construction of the grillages of bridge abutments and pylons, the builders used self-compacting concrete class B35 on sulfate-resistant Portland cement. It provides protection of the foundation from the effects of an aggressive environment and protects the reinforcement from corrosion.
During the construction of bridge supports and pylons, a Geda high-speed passenger-and-freight elevator was used, which lifts up to two tons of cargo. The lift speed is 65 meters per minute.
Artificial peninsulas
For the construction of the M6 pylon on the Nazimov Peninsula, an artificial peninsula was filled, from which wells were drilled for the supports. The construction of the pile foundation of the M7 pylon on Russky Island began with water on a temporary working metal island.
The artificial peninsula was backfilled after the construction of bored piles and sheet piling. It is designed to protect against bulk ships with a displacement of up to 66,000 tons, ice shifts and wave action.
The total volume of rocky and loose soil moved during the construction of technological sites on Russky Island and the Nazimov Peninsula is 1.5 million cubic meters.
Pylon foundation
Pile foundation pylon
Drilling and concreting of piles from water in marine conditions was performed for the first time in practice Russian bridge building. Depths in the area of work at various sites ranged from 14 to 20 meters.
At the base of each pylon there are 120 bored piles with a diameter of two meters. Piles with a non-removable metal shell under the M7 pylon go deep to the level of 46 meters. On the Nazimov Peninsula, the maximum depth of reinforced concrete piles is 77 meters
Rostverk pylons
For the construction of each pylon grillage, approximately 20,000 cubic meters of concrete and about 3,000 tons of metal structures were required. This is the most time-consuming and responsible operation in the construction of the bridge. Tensor sensors are mounted in the body of the grillage to monitor the state of this colossal foundation.
Self-climbing formwork
Concreting of the body of the pylons was carried out using individual self-climbing formwork. Seven working levels overall height 19 meters allow you to simultaneously carry out operations for the preparation of the working seam, reinforcement, concreting, concrete care and finishing on three grips of 4.5 meters each.
The formwork moves independently due to the hydraulic movement of the modular elements. The use of self-climbing formwork made it possible to reduce the construction time of monolithic reinforced concrete structures by one and a half times. With a total volume of concrete per pylon of more than 20,000 cubic meters, this is a significant gain in time.
The superstructure of the cable-stayed bridge Russky Bridge
Reinforced concrete stiffening beam
The anchor parts of the cable-stayed bridge span are located symmetrically with respect to the central span and pylons, and have a length of 316 meters. The span of a continuous structure is made of prestressed monolithic reinforced concrete with a volume of about 21,000 cubic meters.
In the process of reinforcement, in addition to conventional reinforcement, plastic ducts were laid. Steel bundles with high tensile strength are stretched through them.
After the concrete has gained strength, the reinforcing bundles are stretched using jacks with a force of 300 to 370 tons. Then the voids in the channel formers are injected with a special cement mortar.
Metal reinforcement beam
The stiffening beam of the central navigable span of the bridge to Russky Island is all-metal. It is a single box for the entire cross section with a lower and upper orthotropic plate and a system of transverse diaphragms.
The metal stiffening beam consists of 103 panels 12 meters long and 26 meters wide and two adapter panels 6 meters long. Total weight panels - 23,000 tons. The length of the stiffening beam is 1248 meters.
Pre-assembly of panels
The pre-assembly of the panels was carried out on the territory of the production base on the Nazimov Peninsula and in Nakhodka. At the same time, additional operations of fitting multi-ton panels during installation, which was carried out under conditions of strong wind action at a height of 70 meters above the strait, were completely excluded.
Taking into account the fact that in total more than 30 kilometers of butt welds of the first category subject to ultrasonic control were welded, the gain in time was very significant.
Panel lifting
The panels were delivered to the installation site by barges and then lifted by a crane to a height of 70 meters. Positioning of the barge under the assembly unit was carried out using the Russian GLONASS satellite navigation system.
To speed up the construction of the metal stiffening beam, after the twentieth section was lifted, already double panels 24 meters long were submitted to the installation.
Mounting the lock panel
On the night of April 11-12, 2012, an event took place, to which bridge builders had been going for three and a half years. The last panel of the metal stiffening beam was lifted from the Grigorich pontoon. The castle section connected two 546-meter cantilevers of the channel span over the East Bosporus Strait, and the bridge crossing connected Russky Island with the mainland of the city.
The next day, April 13, a video conference was held by Vladimir Putin, during which he congratulated the bridge workers on the completion of the installation work and thanked them for high quality work. “I’ll be honest, I can’t wait to drive over the bridge myself,” he admitted during a live broadcast. Then the command was given - and the builders under the lenses of TV cameras welded the last, "golden" seam.
On the bridge across the Eastern Bosphorus Strait, an improved system of cables with a denser arrangement of strands in the shell is used. The weight of the cable system is 3720 tons, the total length of the cables is more than 54 kilometers.
The shrouds consist of parallel, individually corrosion-protected strands, ranging in number from 13 to 85. Each strand consists of seven galvanized wires sheathed in high-density polyethylene.
The compact configuration of the stay cables with the use of a shell of a smaller diameter helps to reduce the wind load by 25–30%. At the same time, the cost of materials for the pylon, stiffening beams and foundations is reduced by 35–40%.
Guy shell
The shroud of the shrouds is made of two layers: the inner one is black, made of high-density polyethylene, the outer one is thinner, painted in the colors of the Russian flag. The decorative shell is also equipped with a spiral collar designed to protect against vibrations generated by the combined effects of rain and wind.
Comprehensive mechanical protection and monitoring of the manufacturing quality of all cable elements provide high strength, endurance and corrosion resistance. The estimated service life of the shrouds is at least 100 years.
