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.

The new bridge, named the Fatih Sultan Mehmet Bridge, was completed in 1988 and represents the core of the project. At the time of its completion it was the fifth longest suspension bridge in the world. Currently, about 150,000 vehicles cross the Fatih Sultan Mehmet Bridge daily, thanks to its construction the urban area has been extended to zones that were practically uninhabited before. The result of this has been an increase in the size of the city by more than 30%.

Client: General Directorate of Highways