Obskaya – Bovanenkovo railway bridge over the Yuribei river
The Obskaya - Bovanenkovo Railway is the main transport route in the direction of the Bovanenkovo gas condensate deposit, the largest deposit in the Yamal Peninsula. The railway will facilitate year-round deliveries of equipment and building materials, as well as the shipment of liquid commodities, including gas condensate, from the peninsula.
The railway will be 572 kilometres long, including a 525-km stretch in the direction of Bovanenkovo. 472 km of tracks have been laid to date. The railway line has five stations, 12 sidetracks and 70 bridges with a total length of 12 km. About 7,500 workers are involved in its construction.
All tracks, complex metal structures and thermal-insulation materials are Russian-made.
Regular traffic along the 525-km stretch between Obskaya and Bovanenkovo stations is scheduled to open in January 2010. There are plans to open regular traffic along the 47-km stretch between Bovanenkovo and Karskaya stations in September 2010.
Despite the harsh climate, swamps and numerous rivers crisscrossing the Yamal Peninsula, the construction of the Obskaya - Bovanenkovo railway is exceeding the pace of Soviet-era construction projects by over 100%.
The section between the railway's 331st and 335th kilometres, namely, the flood-land of the 500-km-plus Yuribei River, the largest river in the Yamal Peninsula, was initially considered the most difficult part of the construction project.
The Yuribei River, with a basin of nearly 10,000 sq km, flows along salty permafrost, crosses the Yamal Peninsula and falls into the Baidaratskaya Bay in the Kara Sea. In winter, the river turns into a narrow icy ribbon. In summer, when the tundra snow melts away, the Yuribei River floods the vicinity and becomes several kilometres wide for only two to three weeks.
Local residents call it the River of Life because their main sacred places are located along its banks. Moreover, valuable fish species migrate along its 15-km-wide flood-land in spring. About 40 bird species also hatch their offspring in the river's flood-land. The Yuribei River is a traditional fishing and bird hunting area.
The indigenous population and Arctic nature buffs consider this river a real wonder. Archaeologists know its name very well. In 1998, a frozen four-month baby mammoth was discovered there. In May 2007, reindeer breeder Yury Khudi found a well-preserved baby mammoth that had perished over 10,000 years ago in the big bend of the Yuribei River. This is the most unique and complete mammoth carcass located to date. Unlike all other carcasses, this mammoth's trunk, eyes and residual wool are extremely well preserved. Scientists called the female baby mammoth Lyuba, the fifth mammoth carcass located to date.
In December 2007, Russian energy giant Gazprom started building a bridge overpass across the Yuribei River's flood-land. Due to a harsh climate and geological conditions, the overpass was only constructed in winter. Builders were forced to renounce the traditional ground-filling and embankment-formation process used in railway construction.
They chose an unorthodox engineering solution, elevated the roadbed above the water and built a huge 3,893-metre-long overpass. 110 pillars with a diameter of up to three metres were sunk 30 to 60 metres into the ground.
Expensive modern equipment, drilling-crane units capable of operating on permafrost in subzero temperatures were used to drill wells and to install various structures. Construction crews preferred Russian-made technology.
Most specialised equipment was developed at production facilities in the Urals Federal District. For instance, custom-made pipes with a diameter between 2.2 and 3.5 metres were developed and manufactured in Chelyabinsk and subsequently used as bridge pillars. The Urals Automotive Plant upgraded various motor vehicles for the construction project. Custom-made off-road skidders for delivering 70-tonne girder-type bridge sections along frozen winter roads were developed in Tyumen.
The bridge overpass across the Yuribei River was constructed according to the single-hinge principle. A special fastening system distributes any load along the entire bridge. Whether the train accelerates or brakes on the bridge, its movements influence the entire structure, causing it to move forwards, backwards or down. The fastening system reduces outside influence, evenly distributing the load between all bridge pillars. The total temperature linear shift of bridge sections is 3.6 metres.
Due to unprecedented temperature fluctuations in the Yamal Peninsula (ranging from minus 60 degrees C in winter to 40 degrees C in summer), the length of bridge sections may vary by almost three metres. However, precise engineering calculations take this factor into account, enabling the bridge to withstand six-fold loads.
Bridge pillars are sunk into permafrost with 70% water content. The bridge has been literally fused into an icy brine. Cryopegs, layers of unfrozen ground that are perennially cryotic (forming part of the permafrost), can only be found in the Yamal Peninsula. The bridge therefore rests on a surface which is unable to withstand any loads. It is extremely difficult to sink pillars into such ground, whose mobility and stability depends on seasonal temperature fluctuations. The builders, who relied on data provided by specialised Russian Academy of Sciences' institutes and laboratories, had to fuse the pillars with the tundra, the way a tree is planted in the ground.
The Construction Industry Research and Production Institute and Moscow State University of Railway Transport have developed numerous technologies and production processes. Various R&D, prospecting and design agencies, including the Yamal Engineering Centre, LenGiproTrans, the Research Institute of Transport Construction (TSNIIS), YamalGiproTrans, the Morissot Institute designing bridges, transport junctions and artificial structures, TAIS-S, as well as students of the Moscow State University of Railway Engineering and engineers of the MostoStroi-13 bridge-construction company, helped design the bridge overpass and chart engineering and production solutions.
The global construction industry has never seen a similar project to date. The Yuribei bridge overpass is the world's longest Arctic bridge. Such facilities have never been constructed in arctic regions before. It took 349 days to build the Yuribei bridge overpass measuring nearly 4,000 metres long. Up to 20 running metres were constructed per day, a record that remains unbroken to this day.
The 65,000-tonne bridge overpass across the Yuribei River's flood-land comprises 110 pillars, 180,000 high-strength bridge bolts keeping the tracks together, 82 bridge sections measuring 34.2 m each, two sections measuring 110 m each and 25 more sections measuring 34.2 m each. Motor vehicles and tractor crawlers delivered over 30,000 tonnes of metal structures to the construction site. Over 6,500 cu m of permafrost was drilled during the installation of pillars. Nearly 12,000 cu m of concrete was produced and placed inside pillar structures. The total length of welding joints is almost 25 km. The bridge construction project involved over 3,300 workers.
Designers and builders prioritised environmental protection while working on the Yuribei overpass, which is constructed in line with the wishes of reindeer breeders. The bridge crosses the entire flood-land and makes it possible to preserve the entire river ecosystem. Nor does it disrupt fish migration routes to spawning grounds during spring floods. The builders also guarantee that the indigenous population will have no trouble crossing the bridge. Special overpasses were built near reindeer breeding grounds.
A town for builders working in shifts, constructed near the bridge overpass, features comfortable modern housing, a canteen and a laundry facility, satellite television, Internet access and even mobile communications, which were unknown in the tundra only a short time ago.
The town's new administrative facility and service centre comprises a permanent clinic featuring state-of-the-art diagnostic equipment, a dentist's office, a general practitioner's office, a physical therapy ward, an ultrasonoscopy room, a dressing ward, an isolation ward and a first-aid station. Broadband Internet access transmits electrocardiogram and ultrasonoscopy data to any Russian clinic, as well as medical centres in Tyumen, St Petersburg and Moscow. Patients and doctors can discuss various treatment options with the best specialists online. Apart from builders, local nomadic ethnic groups are treated on a priority basis.
In 2008, the Yuribei River won the semifinals of the Seven Wonders of Russia contest organised by Izvestia, a respected daily, Rossiya TV channel and Mayak radio station. The unique Yuribei River bridge was named the Sensation of the Year during the awards ceremony of consumer-trust leaders in the Tyumen Region and named the Main Regional Wonder by local residents at a contest called Seven Wonders of the Tyumen Region.
