Heavy plates for the tunnel boring machine in Istanbul

End of 2016, 100,000 cars will cross the Bosporus 100 m below sea level. The ride from the European side of Istanbul to the Asian side will just take 15 compared to 100 minutes today. Air pollution and CO₂ emission will be reduced significantly. The Herrenknecht tunnel boring machine, mainly made of Dillinger heavy plates, set standards more than 100 m below Bosporus sea level at up to 11 bar water pressure.

22nd August, 2015 was the day of breakthrough under Bosporus. The mixed shield made by Herrenknecht with a diameter of 13.7 m connected Europe and Asia below sea level. After 16 month below Bosporus, the showing up to the tunnel boring giant sets new standards in tunnel boring technology. The water pressure is 11 bar at the deepest point 106 m below sea level. The ground below Bosporus is difficult and wears the boring tools quickly. To exchange the tools safely various safety features were developed. The cutting wheel is accessible from the back side through special air lock systems. Thus, the tools could be exchanged safely under atmospheric pressure.

Dillinger could deliver more than 1,000 to of heavy plate made of different constructional steel grades for this project. The internal cleanliness of Dillinger steel allows for reliable and safe fabrication of the welded structure of the machine. Time is money in project business. Thus, the plates had to be delivered to Herrenknecht and subcontractors with very short lead times and exactly coordinated with the fabrication plan. This is the Dillinger contribution to the on-time breakthrough 22nd August, 2015.