Kinali-Sakarya motorway and second bridge over the Bosphorus

Name of Project:

Kinali-Sakarya motorway and second bridge over the Bosphorus


General Directorate of Highways

Construction period:
November 1985 - December 1994

Istanbul, Turkey's economic capital, is situated on both sides of the Bosphorus Strait, which separates Asia and Europe. The first permanent link, the Bosphorus suspension bridge, was constructed by the Turkish government in 1973. The construction of the 247 km Kinali - Sakarya motorway, which includes the second Bosphorus bridge, was decided as a response to the growth of the population and increasing communication needs.

The new 247 km motorway links the cities of Kinali (Tracia, European side) and Kazanci, near the Sakarya river (Anatolia, Asian side).

The project was divided into four lots:

Lot 1. Construction of 62 km of motorway on the European side, from Kinaly to Mahmutbey; 51 km consists of dual-lane carriageways, while the remaining 11 km consists of 3-lane carriageways.

Lot 2. Construction of the second bridge over the Bosphorus, in Istanbul, approximately 5 km north of the existing bridge, and 37 km of four-lane carriageway motorway links to the bridge. This was the most important part of the project and included two cut & cover tunnels, two overpasses and 14 viaducts, whose piers are constructed on pile foundations.
The new bridge has a single 1,090 m span. The steel piers stand on concrete foundations, on either side of the strait. About 24,000 t of structural steel were utilised for the piers and deck, and 9,450 t of high-strength steel for the cables. The substructures required excavation of 600,000m³ of rock and 140,000m³ of concrete.

Lot 3. Construction of a 45 km motorway with a two-lane and a three-lane carriageway, on the Asian side, from Çamlica to Gebze.

Lot 4. Construction of a 73 km motorway with a two-lane and a three-lane carriageway, on the Asian side, from Izmit to Sakarya, including spur roads. This was the longest section of the motorway and was subdivided into two parts. The first part was constructed in a mountainous area with tunnels linking three consecutive viaducts. The second part is located in a flat area along the northern shore of a lake, reaching the end point with a viaduct built on foundation piles in a river bed.

The Kinali-Sakarya motorway and second suspension bridge over the Bosphorus are one of the largest projects ever executed under a single contract in Turkey.

Excavation: 70,000,000 m3
Fills and embankments: 46,500,000 m3
Base and sub-base: 4,900,000 m3
Asphalt and paving: 5,540,000 tons
Concrete for main structures (viaducts and bridges): 1,330,000 m3
Concrete for minor structures: 800,000 m3

Reinforcing steel for concrete: 200,000 tons

Underground concrete: 50,000 m3


Last update: 18/09/2013