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Eurasia Tunnel represented one of the most monumental engineering and private mobility projects of recent years. It is a 5.4 km double bridge-tunnel that connects the European and Asian parts of Istanbul with a route of 14.6 km. It crosses the Bosphorus under the seabed at a maximum depth of 106 meters. The unprecedented combination of multiple complexities has consistently kept technicians and operators in suspense. It was something new, never realized before. The Turkish company Yapi Merkezi and the South Korean company SK E&C have formed a joint venture for the management and completion of this work. Investments of billions of euros came from international institutions and banks. Contractors have contacted SMA to request a proposal to supply the devices in and out of the tunnel. They were then suggested to the customer which devices to use in the various critical points through the positioning in the plan and the supply of the complete device. The client's goal was to create a safe and avant-garde road tunnel that could in some way also respect aesthetic canons that recall modernity.


The tunnels are highly critical concerning safety, an element that requires a specific management method. Every minimum road risk (accidents, malfunctions of a vehicle, possible fires) in a tunnel is greater: that's why for the contractors of this project the safety issue had to be managed perfectly! In this specific case, the impact Crash cushions had to be positioned near the singular points with a particular risk of impact and had to be installed without creating any hitches. In fact, given the presence of obstacles on the construction site (electrical cables, expansion joints), it was necessary to create ad hoc solutions so that the work continued without difficulty. Another critical issue was represented by the speed and costs of realization of the work, which, in other words, meant the consideration in the design analysis phase also of:
  • transit time of materials;
  • customs clearance times and costs;
  • conditions in which the work is carried out (in this case at night), trying to make the best of the daily hours that SMA had available to complete its part in this work.


SMA proposed to the client different types of impact Crash cushions by positioning the devices in front of the obstacle to be protected and supplying them. Impact Crash cushions were installed in tunnel niches, bypasses, and in front of toll stations. Thanks to our engineering consulting service, we have provided ad hoc solutions in accordance with the configuration of the obstacle to be protected. Crash cushions had to have specific characteristics:
  1. Be fireproof: plastic, in fact, in tunnels is highly discouraged - or just not allowed by law, as happens in Italy - because it is flammable; SMA produces devices that are completely made of steel, which do not increase the risk of fire, as well as being much more resistant to temperature changes;
  2. Have the smallest possible footprint: an attenuator that was too long would have prevented vehicles from using the bypass for any emergency stops. When it comes to a gallery, the less space the shock Crash cushions take up, the better. However, you can not give up safety performance, to the point that it is inadequate, especially on an underwater road with very high traffic of people and goods. The Leonidas SMA Crash cushions are special in the way they combine Maximum Performance with Minimum Footprint;
  3. Be easily repairable: in the event of an accident against the attenuator, it is necessary to restore the device in the shortest possible time. SMA Leonidas is repairable in just 30 minutes;
  4. Respect a certain aesthetic criterion (the Crash cushions had to be orange): SMA devices are all made of Hot Galvanized Steel, but on request, it is possible to carry out a powder coating in the desired color.
This engineering and industrial work together was done taking into serious consideration the delivery time of the project. SMA boasts a 99.2% accuracy on delivery times, and, especially in a monumental work like this, respecting the agreements became essential.


We have therefore managed to bring home a result that has fully satisfied us, putting a bit of Pride and Italian ingenuity in a work of international importance. We have learned a lot, and we now have a wealth of knowledge and experience that allows us to face any project with solidity. In fact, it is in such an unprecedented context that we have been able to put our skills to good use, making the SMA group grow even more. Once the tunnel was completed we had the honor of attending the inauguration ceremony and receiving from the Turkish authorities a gift that we will remember forever. At the presentation of this mammoth work, the collection of commemorative stamps for the birth of the Eurasia tunnel was delivered to us and all our colleagues. We were incredibly surprised to see that one of our Crash cushions was portrayed on one of these stamps. For SMA it was an unprecedented recognition, which gave even more light to the whole team of experts who make our team so performing.

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