Engineering, Procurement, and Construction of Third Bosphorus Bridge

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Hyundai E&C’s technology completes construction of new Silk RoadHyundai E&C’s technology created a new landmark in Turkey serving as a bridge between Asia and Europe. The 697.4-million-dollar Third Bosphorus Bridge project is to build a bridge between Garipce in Sarıyer on the European side and Poyrazkoy in Beykoz on the Asian side. About over 400,000 workers were mobilized on an annual basis. The opening ceremony, held on August 26, was attended by about 1,500 officers including President Recep Tayyip Erdogan and Prime Minister Binali Yıldırım and around 25,000 citizens and broadcast live across the country.The newly opened bridge is not comparable in size. Compared to the First and Second Bosphorus Bridges completed in 1973 and 1988, respectively, the Third Bosphorus Bridge has an almost 1.4 times longer span between towers and over 2 times higher pylons. It carries four motorway lines and one railway line in each direction. The central span between two pylons reaches 1,408m. The two main towers are 322 meters high, higher than the 300-meter Eiffel Tower and the highest pylons among those of cable-stayed bridges and suspension bridges around the globe.Adopting a whole new method of bridge constructionThe construction of the Third Bosphorus Bridge in Turkey was a huge challenge nobody ever confronted in the history of bridge construction. Hyundai E&C had to reduce construction period as well as construct the hybrid cable-stayed suspension bridge. The reason why the cable-stayed suspension system was adopted is that long-span suspension bridges sway too much to feature railway lines in general.Each main suspension cable connecting between the towers is made of 127 high-strength steel strands (5.4mm in diameter) bundled, which is called the prefabricated parallel wire strand(PPWS) method. The main suspension cables can hold 90,000 tons of heavy vehicles.The new bridge has a span of 1,408m between the pylons and a deck height of 78 meters. Even mega sized containers ships can travel under the bridge without troubles. Hyundai E&C also utilized the slip forming method in which steel reinforcing rods are placed into the castin-place concrete.The construction site never stops around the clockWind is one of the biggest obstacles to marine bridge construction which involves construction work at height and transportation of heavy equipment. In this sense, the Third Bosphorus Bridge project had the worst conditions such as frequent fog and gust of wind with a speed of 30m/s.The management of about 1,000 multinational workers was another challenge. Intensive training sessions and special training courses on safety rules were offered to workers in order to improve their safety consciousness. As a result of the thorough compliance with our 12 safety rules and elaborate safety-related plans, the construction site could achieve no accidents across all fields of construction.

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