The project is expected to reduce the travel time between Kazlicesme and Goztepe from 100 minutes to just 15 minutes. The 5.4km twin-deck tunnel will be built underneath the seabed of Bosphorus, qalso known as the Istanbul Strait. The project also involves improvement and widening of the roads leading to the tunnel.
A ground-breaking ceremony for the project took place on 26 February 2011. Construction is expected to be completed in 55 months, with a daily capacity of 120,000 vehicles in both directions. An investment of $1.1bn is being made in the project.
Eurasia Tunnel Project
"Construction is expected to be completed in 55 months, with a daily capacity of 120,000 vehicles in both directions."
Proposals for establishing a transportation connection across the Bosporus by means of a tunnel had been considered in the 19th century, but the project was abandoned due to the lack of technology. With many similar projects being constructed in the 21st century, the idea was revived. The project was included in the Transportation Master Plan formulated by the Istanbul Metropolitan Municipality in 1997.
A pre-feasibility study was carried out based on findings in the master plan in 2003. In 2005, the Republic of Turkey Ministry of Transportation issued a contract to Nippon Koei to carry out a feasibility study for the project. Factors such as environmental standards, cost, risk, bridge locations and equilibrated distribution across the tunnel route were included in the study.
DHL, which includes the Republic of Turkey Ministry of Transport General Directorate of Railways, Harbors and Airport Construction - Türkiye Cumhuriyeti Ulastirma Bakanligi Demiryollar and Limanlar ve Hava Meydanlari Insaati Genel Müdürlügü, formulated the technical specifications of the road.
The Asian Highway Network (or the Great Asian Highway) is a 141,000km network of roads running across 32 countries. It is being built with an intention to improve transport facilities throughout these nations and provide road links to Europe.
Build Operate Transfer model was chosen to be the best option for the construction of the tunnel. In December 2006, AYGM tendered the Istanbul Bosporus Tube Crossing Project. In January 2009, the contract was pre-signed by Turkish Korean Joint Venture, which later registered its name as ATAS (Avrasya Tüneli Isletme Insaat ve Yatirim - Eurasian Tunnel Operation Construction and Investment). The implementation contract for the project was signed in February 2011. ATAS will be responsible for construction, operation and maintenance for a period of 25 years, 11 months and nine days.
The project site is located 1.8km south of Marmaray's Strait crossing, which is currently under construction. The tunnel will help Istanbul ease its intercity traffic and reduce the traffic load on the Bosporus Bridges.
The tunnel will also contribute to the growth of Istanbul's air transport by providing the most practical link between the city's two airports: Ataturk Airport and Sabiha Gokcen Airport. By decreasing distance, it will indirectly contribute to reductions in fuel consumption, noise pollution and CO2 emissions.
Eurasia Tunnel Project design
The total length of road under construction is 14.6km. The whole project is divided into three segments: European Side Approach (5.4km), Asian Side Approach (3.8km) and Istanbul Side Approach (5.4km). 3.3km of the tunnel passes underneath the seabed.
The main criterion considered while designing the project was safety. The tunnel has been designed to withstand earthquakes of magnitude up to 7.5 on Richter scale. The maximum depth of the tunnel below the seabed is 61m, while the overburden is 25m underneath the seabed and the lowest tunnel level is 106.4m.
Eurasia Tunnel Project construction
The tunnel will be constructed between Kazlicesme on the European side of Istanbul and Goztepe on the Asian side of Istanbul.
The European side segment includes construction of five underpass U-turns and seven pedestrian overpasses between Kazliçesme and Sarayburnu along Kennedy Street. The entire 5.4km segment will be widened from 3x2 lanes to 2x4 lanes.
Construction of the 3.8km Asian side segment involves widening of 2x3 and 2x4 lanes of D100 road to 2x4 and 2x5 lanes respectively, as well as construction of two bridge intersections, one overpass and three pedestrian footovers.
"An investment of $1.1bn is being made in the project."
Construction on the Asian side will commence first and will progress to the European side with the drilling of a tunnel 25m underneath the seabed of Bosporus strait.
The approach roads on either side will be widened to eight lanes. The current junctions and crossings will be substituted by underpasses. New overpass footovers will be constructed for pedestrians. The approach roads will be handed over to the Istanbul Metropolitan Municipality after the completion of renovations and widening.
Eurasia Tunnel Project contractors
Avrasya Tüneli Insaat Isletme ve Yatirim is executing the project as the lead contractor. It is a consortium of Turkish companies Yapi Merkezi and SK E&C, and Korean companies Samwhan Corp. and Hanshin.
Environmental and Social Impact Assessment (ESIA) of the project was carried out by ERM (Environmental Resource Management) and ELC Consulting and Engineering Group, under a contract with ATAS.
LeighFisher, a global management company, was consulted for analysis of the tunnel's traffic and revenue forecasts.