Istanbul's new metro bridge -- the subject of many news stories due to its effects on the city's historic skyline -- is nearing completion.
In fact, the so-called “pearl of Istanbul,” or the Golden Horn, has been literally re-drawn with this project, and it is now just days before the Taksim metro descends all the way to Yenikapı. In the meantime, the metro station above the bridge set to serve many thousands has finally emerged before our curious eyes. Though work is proceeding fast and furiously on this line, the first test drive with Prime Minister Recep Tayyip Erdoğan is expected to take place on the same day as the opening of the Marmaray, on Oct. 29, 2013, and the complete tests will last two months. The bridge itself will open for service in January 2014.
This bridge, commissioned by the Istanbul Municipality, first appeared on the general agenda in 1952, while construction began in 1982. In 1990, the Protection Board approved the building of this line. By 1998, bids were taken for the building of new tunnels, and the Şişhane-Karaköy and Unkapanı-Yenikapı lines opened up. As for a bridge spanning the Golden Horn, 21 projects were presented for approval to the Protection Board by 2005. None of those put forward were deemed complementary to the city skyline, however. In 2005, a project designed by architect Hakan Kıran was approved by the Protection Board, though it was controversial from the very beginning. Work on the bridge proceeded, but only in the shadow of serious debates over the bridge, as the supporting towers in this first project were projected to reach a height of 82 meters. The towers' height was reduced a number of times following warnings that Istanbul could be removed from the UNESCO list of World Heritage sites.
Because of warnings over the possible effect on the view of the Süleymaniye Mosque, the supporting towers' height was cut to just 65 meters, while the starting point for the steel hanging parts of the bridge was dropped to 47 meters. It was decided that a report would be offered at every stage of the project. The most recent such report was publicized in Paris in April 2012. In fact, almost every aspect of the bridge -- from the heights of its various components to its color -- was decided only after discussion with UNESCO. The question of what color the bridge should be was decided only after exhaustive rounds of photographing the bridge and its surrounding area in every season. After numerous studies and much work on the surrounding colors, it was decided that the bridge would be grey, and the metro station on top of it light brown.
The Taksim-Yenikapı metro line set to use this bridge will be around 5.2 km long and have four stations. The Taksim metro will emerge at the base of Şişhane in Azapkapı and will then pass over the Golden Horn by bridge, re-entering the earth at the edge of the hill on which the Süleymaniye Mosque is located. The bridge itself boasts not only a metro station, but also pedestrian paths. The bridge will allow pedestrians to walk across the Golden Horn, overlooking the historical peninsula from 13 meters above.
The length this new bridge runs above the water is 460 meters; with the addition of the Unkapanı and Azapkapı extensions, the bridge's length is 936 meters. The bridge, which rises 13 meters above ground, will have five supports. While the bridge stands on loose alluvial rock, massive rods have been driven beneath the legs of the bridge to prevent long-term or short-term collapse or slippage. In fact, these 36 rods driven some 110-120 meters below sea level support the bridge. These are steel rods manufactured especially in Poland, and they have been placed only after calculations that are precise to the millimeter. In fact, each rod was proceeded by special archeological digs to ensure that no historical items or pieces would be damaged by the rods' placement. Of course, this was not an easy process.
On the Unkapanı side of the bridge, there is an opening section of the bridge that will allow for the passage of large ships. During the summer months it will be opened once a week between 1 a.m. and 5 a.m., and during winter months, twice a week at these hours. With this bridge, the Istanbul metro will reach the Yenikapı Transfer Station uninterrupted. At Yenikapı, there will be transfers available to both the Marmaray and Aksaray-Airport lines. It is expected that some 1 million passengers per day will use this line, which will open for service in January 2014.