Seven Hills Seven Tunnels Project
The Istanbul Metropolitan Municipality
KİS-MAK Ordinary Partnership
Start and End Date
2006 - 2008
Total Concrete Amount 405.000 m³ Concrete Classes Shotcrete 420 123.000 m³, C 25/30 and C 30/37 Gross concrete 282.000 m³
Projected to be used for the next millennium, the “Seven Hills Seven Tunnels” project has been designed to ease Istanbul’s intense traffic. OYAK Concrete has supplied all of the ready-mixed concrete used so far. As part of this project, following tunnels have been built:
Tunnel 1: The Piyalepaşa – Kağıthane Tunnel, 3,023 m in length. Vehicles enter the tunnel at Kasımpaşa – Piyalepaşa, pass under the Okmeydanı – Çağlayan district and exit at Kağıthane, connecting to TEM through Sütlüce Connection Road.
Tunnel 2: Dolmabahçe–Bomonti Tunnel, 4,091 m in length. The route starts with the tunnel entrance at Kadırga, which is located on the northern side of İnönü Stadium, passes under Taksim bypassing Taksim – Kabataş–Karaköy traffic, and goes under the Feriköy district, ending with the Kasımpaşa (Bomonti) Piyalepaşa exit and connecting to the E-5.
The tunnels have been built using earthquake-proof methods. The project was planned to enable the tunnels to be used as a sanctuary, hospital, and transportation road in the event of a disaster. Fans measure carbon monoxide levels and start operating automatically when the ventilation rate falls below 8 km/h. There is a surveillance camera once every 100 m. Emergency exits are placed every 250 m. All equipment within the tunnel can withstand a temperature of 250°C for two hours. Temperature changes are measured with receivers. Corrosion-resistant and heat-proof special concrete is used instead of asphalt by adopting a different technology, as the toxic gases given off by asphalt could pose a danger in case of a fire. This application is a first in this field, and for the first time in Turkey ready-mixed concrete has been used in a tunnel pavement instead of asphalt.