Extra.6

Aug. 7, 2014

Japan Society of Civil Engineers
International Activities Center

International Activities Center News: Special Issue 6■ Introduction
The Railway Bosphorus Tube Crossing, Tunnels and Stations (Marmaray Project) in Istanbul, Turkey
was opened on October 29, 2013. The success of this challenging project, which was completed withthe use of advanced technologies in a harsh natural environment, has been highly acclaimed inTurkey, in Japan, and throughout the world.
The JSCE International Activities Center has compiled this special issue as a means of sharing
information about this project with our international members, associated academic societies,universities, research institutes, and alumni, with the added goal of helping students and young
engineers to develop a greater appreciation of civil engineering. We hope you will enjoy reading it.
JSCE International Activities CenterMarmaray Project Linking Asia and Europe Across the Bosphorus Strait

Takashi Imaishi
General Manager, Civil Engineering Department, International Operations Headquarters, Taisei Corporation
Imaishi joined Taisei Corp. in 1981. His primary area of specialization is shield tunneling. His past projects
have included the Tokyo Bay Aqua-Line (14 m diameter), Metropolitan Area Outer Underground Discharge
Channel (12 m diameter), and Underground Regulating Reservoir (13 m diameter) of Kanda River on Ring
Road No. 7 within Japan, and the Railway Bosphorus Tube Crossing, Tunnels and Stations Project (8 mdiameter) internationally. Prior to assuming his current position in January 2014, he served as manager of theCivil Engineering Technology Development Department of the Taisei Technology Center.

■ Istanbul, a Cultural Gateway Between East and West
The city of Istanbul has a rich history of diverse ethnicities and cultures, from the ancient Greek,Roman, and Ottoman empires to the present-day Republic of Turkey. Istanbul surrounds the Sea ofMarmara, which is connected to the Black Sea in the north and the Mediterranean and Aegean Seasin the south, and it is also a hub of land transportation. Istanbul is truly a cultural gateway between
the East and the West.

Black Sea

Asian side
Bosphorus

European side

Istanbul
41st parallel
TurkeySea of Marmara

Fig. 1

Istanbul, capital of the Republic of Turkey

Fig. 2The Bosphorus Strait plays a key role inocean transport.

■ Turkey's 150-Year Dream of Linking
Europe and Asia
Istanbul, Turkey's largest city with apopulation of over 15 million, is divided by
the Bosphorus Strait. With only two east-west
bridges connecting the city's European sideand its Asian side, this resulted in chronic
congestion with increased air pollution. To
relieve these problems, construction work on
a subway tunnel under the strait was begun in2004
underanEPC(Engineering,Fig. 3
Procurement, and Construction) turnkey
contract with Japanese financial backing. This
concept was imagined 150 years ago inTurkey, as illustrated by an engineer's design
drawing from 1860.

Turkey's 150-year dream was depicted in a
19th century drawing.

■ Two World Firsts in This Technically Challenging Project
The project consisted of a 13.6 km rail tunnel with a crossing of about 1.4 km under the Bosphorus
Strait, along with the rail line, four station buildings, and equipment. To build the undersea tunnel
portion under the difficult environmental conditions of a strait with fast and complex tidal currents, atide prediction system informed by weather forecast data was developed, and the undersea portionwas completed by the immersed tunnel method at 60 meters, the greatest depth for use of this method
anywhere in the world. Meanwhile, the methods of shield tunneling and NATM (New AustrianTunneling Method) were used in combination for construction of the land portions of the tunnel,culminating in the world's first undersea direct connection between a shield tunnel and an immersedtunnel. The highly demanding technical challenges of this project were overcome usingstate-of-the-art tunnel construction technologies.

(Asian side)
Project route
Bosphorus
StraitSirkeciStation(European side)

The underground project route was located near a World Heritage site.
European sideSirkeci Station

Fig. 5

Cut & cover

Shield tunnel

Cut & coverstationCut & cover

BridgeCut & cover tunnel

Above-groundstation

Shield tunnel

ShieldtunnelÜsküdar StationAyrılık Çeşmesi Station

Bosphorus Strait

Immersed tunnel

NATM
stationCut & cover station

Yenikapi Station

Invert elevation
Approximately 60 m

Kazlıçeşme Station

Asian side

Shield tunnel

Cut & coverFig. 4

BridgeFillFill

Cross sectional view of the tunnel, built using every kind of tunnel construction method.

End of immersedtunnel
Shield machine

World's first floating construction of RC immersed tunnel elements.
Position control and deformation control were key points whencompleting the floating RC immersed tunnel elements.

Fig. 6

Floating construction of RC immersedtunnel elements
Fig. 7

Direct connection between immersed
tunnel and shield tunnel

■ Tunnel Opened on 90th Anniversary of Turkish Republic After Extensive ArchaeologicalInvestigations
In such a historical city as Istanbul, archaeological investigations for buried cultural artifacts can bequite time-consuming. The first train traveled through the tunnel nine years after work began in 2004,
much later than initially anticipated, on October 29, 2013, the 90th anniversary of the Turkish
Republic. Turkish Prime Minister Erdoğan invited Japanese Prime Minister Abe and the prime
minister of Romania to participate in the opening ceremony, and many residents gathered in a park byÜsküdar Station on the Asian side for this grand inauguration. It was a day full of emotion for thoseof us who played a part in its construction. Sirkeci, the terminal station, was made famous by Murderon the Orient Express, a novel by Agatha Christie; and now that a new station has been completed
under it, the route of the Orient Express, which started operating from Paris East 130 years ago, isconnected across the strait. This memorable achievement will give rise to new narratives, in addition
to improving convenience.

Japanese PrimeMinister ShinzōAbeTurkish Prime Minister
Recep Tayyip ErdoğanFig. 8

The opening ceremony on October 29, 2013 was a time of deep emotion.

■ Being a Professional Engineer
I recall my feelings of nervousness and anticipation when I traveled to Istanbul in 2005 to lead theshield construction portion of this project. I was stationed there until 2010, and although six years is along time, it seemed to go by in a flash. This was my first overseas assignment after 24 years ofexperience with projects in Japan. Although I had six years of domestic experience as a project sitemanager, I had never served as a project manager outside Japan previously. I struggled every day tocommunicate in English amid the people, culture, and natural environment of an unfamiliar setting.
This was the company's first project in Turkey and first EPC contract for civil engineering
construction (FIDIC Silver Book), as well as Turkey's first immersed tunnel and first use of slurryshield tunneling. With so many firsts, the project involved one difficulty after another and turned out
to be much more challenging than I could have imagined. However, by working in that environment,
I truly sensed how much this project meant to the people of Turkey. I gained a renewed awareness ofthe fact that while civil engineering projects involve a great deal of hard work, they are also very
important to people. I would like to encourage all the young people who want to work overseas tokeep developing the courage and tenacity that they will need in order to step out into new fields asprofessionals.

Fig. 9At a party with local staff members■ Postscript
The subject of this special issue, the railway construction project across the Bosphorus Strait, wasalso covered in the first symposium in a series organized by JSCE on international work by civilengineers, held on April 3, 2014. The response was even better than anticipated, indicating that thelevel of interest in Japan is on the rise again.
The JSCE International Activities Center will continue to make information widely available byholding symposiums and issuing the IAC News.